BIODIVERSITY CONSERVATION

CONTENTS

LESSON I

1.1  Understanding our Environment

1.2  Brief History of Conservation Environmentalism

1.3  Human Dimensions of Environmental Science

LESSON 2

2.1 Environmental Systems

2.2 Elements of Life

2.3 Energy

2.4 Energy of life

2.5 From species to Ecosystem

2.6 Biogeochemical Cycle and Life processes

LESSON 3

3.1  Species populations interactions and communities

3.2 How species diversity arises

3.3 species interactions shape communities of species

3.4 The growth of species population

3.5 Human Populations

LESSON 4

4.1 Biomes and Biodiversity

4.2 Terrestrial Biomes

4.3 Marine Ecosystems

4.4 Freshwater Ecosystems

4.5 Biodiversity

4.6 Benefits of Biodiversity

4.7 Threats of Biodiversity

4.8 Preserve Biodiversity

4.9 Endangered Species Management and Biodiversity Protection.

LESSON 5

5.1 Environmental conservation

5.2 World forests and Grasslands

5.3 Grasslands

5.4 Ecosystem preservation

5.5 World parks and preserves

5.6 Wilderness areas

5.7 Wildlife refuges

INTRODUCTION

Life and environment are interdependent. The plant and animal life is affected by various environmental factors and in turn they modify their environment in various ways. Man himself is no exception to it and is involved in a tremendous struggle against the environment. The main theme in ecological studies is the relationship between organism and their environment, so ecology may well be called as 'environmental biology'.

  Ecology is one of the most popular areas in biology. Even the layman and general public are greatly interested in ecology in view of the problems of environmental pollution, over population, human survival, pest control and conservation of natural resources. Ecology is a vast encyclopedic biological subject. To a beginner, at the outset, ecology may appear to be quite confusing and discouraging because it seems so diffuse and incoherent. After all, it must take into account the life habits of over two million different kinds of animals and plants and it consider all matter of influence and interactions among them.                                                                      

DIFFERENCE BETWEEN ECOLOGY AND ENVIRONMENTAL BIOLOGY

From the systemic (thermodynamic) point of view there is no difference between ecology and environmental biology. But when the ecology is concerned with human development or human benefit it is generally known as "environmental biology" by many workers. In environmental biology man is considered as a biotic component, but in ecology usually any biological species is considered as a biotic component. But if one considers human as a simple animal without taking its intelligence as an ecological factor  - there is no difference between ecology and environmental biology.

DEFINITION OF ECOLOGY

Ecology has been defined variously by different classical and modern ecologists with different viewpoints. But no universally accepted definition of ecology has been formulated by any ecologist so far. Some important definitions of ecology are as follows:                                                                                                               

"Ecology is the total relations of animals to both their organic and inorganic environment"

__Ernst Haeckel, 1866          

"Ecology is the science of community"

__ Frederick Clements, 1916

"The scientific natural history concerned with the sociology and economics of animals"

__ Charles Elton, 1927

"Ecology is the science of the relations of all organisms to all their environments"

__W.P. Taylor, 1936

"Ecology is the study of inter – relations of plants and animals with their environment which may include the influence of other plants and animals present as well as those of the physical features"

__ G.L.Clarke, 1954

OBJECTIVES OF ECOLOGY

Ecology has made little progress in the last thirty years in comparison to some other fields of biology particularly molecular biology.

1. The local and geographical distribution and abundance of organisms (habitat, niche,   community, biogeography)

2. The inter-relations between organisms in populations and communities (population ecology)

3. The behavior of organisms under natural conditions (ethology)

4. Evolutionary development of all these inter relations (evolutionary ecology)

SCOPE OF ECOLOGY

  The scope of ecology is quite vast. The study of ecological principles provides a background for understanding the fundamental relationships of the natural community and also the sciences dealing with particular environment such as forest, soil, ocean and inland waters. Many practical applications of this subject are found in agriculture, horticulture, forestry, limnology, oceanography, fishery biology, biological survey game management, pest control, public health,     toxicology, pollution control, conservation, etc                                              

Ecology is a multidisciplinary science and it includes not only the life sciences but chemistry, physics, geology geography, meteorology, climatology, hydrology, paleontology, archeology, anthropology, sociology, mathematics and statistics as well.                                                                                           

CAUSES OF LOSS OF WILD LIFE

1. Loss of habitat:  Rapid increase in human population, coupled with the increased per capital demand of resources, results in the destruction of wildlife habitat. In India the natural environment is threatened not only by the growing human population but also by that of the livestock.                                       

2. Grazing pressure: Constant disturbances through grazing of domestic cattle are usual features of our forests. About 200 Million cattle become a serious threat to our wild life. They not only compete with the wild grazers for food, but also spread dreaded diseases among them.

3. Poaching and hunting: Poaching for meat, skin, fur, ivory, horns and many other animal parts, or simply for fun, constitute another important cause of the recent decline in our wild life wealth.                                                             Old Stone Age man hunted for food and the tradition has been continued to this day.                                                                                                       

4. Capture and export:  Indiscriminate capture and export to some wild animals may also cause rapid decline in their populations. Many amphibians, some snakes and birds are only a few examples of this trade.                                             

5. Animal introduction:  Introduction of an animal where it is not native may cause serious problems. The introduction of goats into the Galapagos island has resulted in the death of large numbers of two interesting reptiles; the land Iguana, which is a small reptile, and giant tortoise, which can live 100 years and weigh upto 230 kg. Goat's do not eat or kill these animals, but they do eat the plants on which they feed.                                                                                           

6. Pollution to the habitat:  Imbalance and deterioration of the forest ecosystem by different polluting agents, biocides, etc., constitute another cause of wild life decline.                                                                                                        

All over the world, particularly in tropical and subtropical regions, DDT has saved millions of lives. Used against agricultural pests, it has been enormously valuable in increasing crop production. But, entrance of DDT in the ecological cycle (food chain) and their magnification to lethal levels caused decline in wildlife.                                                                                                         

TYPES OF CONSERVATION

From the management point of view there are two types of conservations.

1. In-situ conservation

2. Ex-situ conservation

1. In-situ conservation: In-situ conservation approach is conservation of living resources within the natural ecosystems in which they occur. Behind this concept the idea is that not much diversity can be conserved outside the original habitat or ecosystem. The in-situ conservation includes an extensive system of protected areas (PA) such as National Parks, Sanctuaries, Nature Reserves, Cultural Landscapes, Biosphere Reserves, etc. In these protected areas much of the world's biological diversity can live in the maximum biotic potential.                         

2.  Ex-situ conservation: Ex-situ conservation approach is conservation for living resources outside the natural ecosystems in which they originally occur. In this process organisms are maintained in zoos, botanical gardens, genetic resource centers, cultural centers, etc                                                                          

Various organizations have been set up to act in co-ordination and promote nature conservation and wild life management. Wildlife management can be done in the following ways:

1. Study of habitat: In order to protect wild animals a thorough knowledge of their habitat is essential. The interdependence of wildlife and habitat is of a specific local nature generally and research is needed to establish the correct relationship in each case.                                                                                                 

2. Protection of habitat: Protection of habitat against over grazing and browsing is needed for proper management of wild life. Protection given to predators such as tigers and leopards is often of direct value to forests in the greater immunity secured from grazing by cattle and deer.                                                        

The role of water and the value of its conservation and protection for both plant and animal life cannot be over-emphasised. Water is to be retained in the soil and allowed to percolate and more slowly, conditions for which are best ensured by forest practices. It is often more important to regulate water flow properly by flood control dams and ditches, equipped with sluice-gates, than to hastily destroy the sources of water of springs, streams, ponds and wells by such drainage. Wild life conservation and soil conservation both depend on vegetation and are complementary to each other. Fire and excessive feelings can remove both.        

3. Improvement of habitat: Steps should be taken for the development of habitats of wild animals. Habitat improvement is made usually through:                       

    (a) Strip cropping: Ecotones are known to support richest wild life populations, due to edge effect. In terrestrial ecosystems, edge effect may be created by alternating one crop with another.                                                                  

    (b) Development of watering sites: Proper water supply in the wildlife habitat is necessary. Planting of vegetation fringe along the margins of water attracts wild life and provides food, shelter and breeding sites.                                             

    (c) Use of water land: Barren and uncultivable lands can be developed into wild life paradise with due consideration of prevailing local environmental conditions.

4. Maintenance of statistical data of wild animals: For proper management practices statistical data must be maintained. In order to make statements concerning the results of their research, wild life biologist should support their conclusions with statistical tests. In ecology most phenomena are affected by many casual factors, uncontrollable in their variation and often unidentifiable. Statistics is needed to measure such variable phenomena with a predictable error and to ascertain the reality of minute but important differences.                      

5. Regulations affecting wildlife: Regulations in the form of laws has been passed by various countries, giving guide lines for the protection of wild life. In India too, the wild life protection act of 1972 has schedules Ito V, rating the animals according to the risks of survival.                                                                   

6. Ban on hunting: Hunting for pleasure should be stopped.  A dependable census will sometimes indicate need for reduction of population of big game animals, and the controlled hunt will frequently accomplish the necessary kill. Recently such practices have been applied in a few African countries to control the elephant population.                                                                                                    

7. Organisation of veterinary units: For proper maintenance of wild animals there should be some arrangements to treat them by expert persons.                        

8. Wildlife research: Knowledge of the life histories of all wild animals, beneficial and predatory, is indispensable to good management of wild animal resources. It has been found through examination of the stomach contents of African crocodiles that they live partly on fresh-water crabs and cray-fish which destroy the fry of the Tilapia, the main food fish of the Africans. With the disappearance of the African crocodile, the cray fish and the lung fish as well as the otter, all the enemies of fish, are on the increase. Young crocodiles eat water beetles and spiders, while old crocodiles are actually beneficial to fisheries than the reverse. The crocodile and the monitor lizard kept each other in check, the lizard eating the crocodile's eggs while the adult crocodile preys upon the lizard. This balance is now threatened by the destruction of the crocodile for its skin.                                                   

9. Wildlife census: There should be the data for the number of those animals which are at the point of extinction. They should be counted at times so that proper steps should be counted at times so that proper steps can be taken for their protection. It is obvious that any allowable kill of wild animals should be based on the numbers constituting the resource at any time and place. There are many ways in which the population of animals can be estimated. In the case of carnivores, pugmarks have become a useful indicate.                                                                               

                                     

BIODIVERSITY

       INTRODUCTION

Bio-diversity describes the number, variety and variability of living organisms its leads to stability of the ecosystem.

In the process of biological evolution many small and big animals and plants were born and many were ruined for ever due to climate change, earth quake, volcanic corruptions, glaciarisation and other natural disasters. Species which could adapt themselves with the changing circumstances survive still, dinosaurs that could not adapt had dwindled away. Biodiversity of an ecosystem or of an geographical area includes various kinds to trees, plants, animals, birds, insects and even micro-organisms. It has been estimated that in the great store house of the earth's biodiversity the name of 14 lakh of species are enlisted.                                  

DEFINING DIODIVERSITY

Biodiversity, or biological diversity, is the term for the variety of life and the natural process of which living things are a part. This includes the living organisms and the genetic differences between them and the communities in which they occur.                                                                                          

The concept of biodiversity represents the ways that life is organized and interacts on our planet. These interactions can take place on scales ranging from the smallest, at the chromosome level, to organisms, ecosystems, and even to entire landscapes.                                                                                                   

SIGNIFICANCE OF BIODIVERSITY

Biodiversity is a store house of genes. Out of 2.5 lakh species of plants only 5000 Species of plants have been studied properly. Men have identified only 30 to 35 species as food. Many wild species of plants are scattered in many forests of the world. Many valuable genes of plants may be transferred to choiceable plants by the help of gene-technology. The dwarf varieties of paddy plants have been created by the process of hybrid. This resulted into "green revolution".           

Biodiversity maintain balance in nature by keeping the food-chain undisturbed. The herbivores cannot exist without plants; and carnivores cannot survive without herbivores. If the proportion of plant, herbivores and carnivores ratio is disturbed the ecosystem may face severe consequences.                                                 

LOSS OF BIODIVERSITY

The loss of biodiversity has immediate and long term effects on human survival itself. The majority of the world's population still depends on wild plants and animals for daily food, medicine, housing and household material, agriculture, fodder, fuel wood, spiritual substance and intellectual stimulation. For these billions the loss of biodiversity is a direct irreversible attack on their livelihoods sand social security.                                                                                             

The loss is even more direct in the case of domesticated biodiversity. Traditional farmers of the world have developed an incredible variety of crops and live stock. The traditional biodiversity was bred to meet diverse human needs of nutrition, taste, colour, ritual, smell, and to resist drought, flood and pests.

The roots of biodiversity destruction lie not so much in population increase, as in the relations between the communities within each nation, and between the nations themselves. This is responsible for concerning the vast biological resources for the benefit of a small minority within the poor nations, and for the wasteful consumption patterns of the developed nations.                                

BIODIVERSITY ASSESSMENT

Effective biodiversity conservation depends on accurate, up-to-date and accessible information. The UNEP-WCMC (United Nations Environment Programme - World Conservation Monitoring Centre) Division of Early Warning and Assessment aims to support international conservation by providing integrated information of direct policy relevance. The overall goal is to analyze the state of global biodiversity, assess trends and provide early warning of emerging threats. For biodiversity assessment UNEP-WCMC collate and analyze data relating to status and trends in

1. Distribution and condition of marine and terrestrial ecosystem

2. Patterns of species diversity

3. Distribution and abundance of threatened species.

4. Pressures affecting biodiversity

5. Response measures

                                                         IUCN RED LIST

            The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature (IUCN) is the world's main authority on the conservation status of species. A series of Regional Red Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit.

The IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. The aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction.

PROJECT ELEPHANT

Project Elephant was launched in 1992 by the Government of India, Ministry of Environment and Forests to provide financial and technical support of wildlife management efforts by states for their free ranging populations of wild Asian Elephants. The project aims to ensure long term survival of viable conservation reliant populations of elephants in their natural habitats by protecting the elephants, their habitats and migration corridors. Other goals of Project Elephant are supporting research of the ecology and management of elephants, creating conservation awareness among local people, providing improved veterinary care for captive elephants. Project Elephant (PE), a centrally sponsored scheme, was launched in February 1992 to provide financial and technical support to major elephant bearing States in the country for protection of elephants, their habitats and corridors. It also seeks to address the issues of human elephant conflict and welfare of domesticated elephants. The project is being implemented in 13 States / UTs, namely, Andhra Pradesh, Arunachal Pradesh, Assam, Jharkhand, Karnataka, Kerala, Meghalaya, Nagaland, Orissa, Tamil Nadu, Uttaranchal, Uttar Pradesh and West Bengal. 

PROJECT TIGER

Project Tiger was launched in 1972 in India. The project aims at ensuring a viable population of tigers in their natural habitats and preserving areas of biological importance as a natural heritage for the people. The selection of areas for the reserves represented as close as possible the diversity of ecosystems across the tiger's distribution in the country. The project's task force visualized these tiger reserves as breeding nuclei, from which surplus animals would emigrate to adjacent forests. Funds and commitment were mustered to support the intensive program of habitat protection and rehabilitation under the project. The government has set-up a Tiger Protection Force to combat poachers, and funded the relocation of up to 200,000 villagers to minimize human-tiger conflicts.

During the tiger census of 2008, a new methodology was used extrapolating site-specific densities of tigers, their co-predators and prey derived from camera trap and sign surveys using GIS. Based on the result of these surveys, the total tiger population has been estimated at 1,411 individuals ranging from 1,165 to 1,657 adult and sub-adult tigers of more than 1.5 years of age.

FRESH-WATER ECOLOGY

LIMITING FACTORS OF FRESHWATER: PHYSICO-CHEMICAL CHARACTERISTICS OF FRESHWATER ENVIRONMENT

Freshwater environments are highly diversified and marked by a wide range of physic-chemical conditions. Physical conditions vary from those of boiling lakes of volcanic regions to permanently frozen bodies of water in polar or high mountain areas. Chemical conditions may vary from clear lakes of certain high mountains, which contain only a few nutrients, to lakes of inland seas of interior drainage that are so saline that only a few highly specialized forms of life survive. Physico-chemical factors influence fresh water organisms and ecosystem.  The important physic-chemical characters are as follows:

                                                PHYSICAL CHARACTERS

1.      Temperature: The effects of temperature on the physiology of freshwater organisms are as complex as the effects of nutrients. However, because of many unique thermal properties of water (high latest heat, high freezing point, high specific heat etc.), the range of variation of temperature is smaller and changes in temperature occur more slowly in water than in air.                                         

2.      Light: Light influences freshwater ecosystem greatly when light waves encounter the water surface, a part of it is reflected, while another part enters the water and is refracted. The reflection depends upon the angle of incidence of the rays with the general water surface and also upon the degree of water motion.                     

3.      Colour: Colour of any freshwater body may be the result of sky reflection, the colour of the bottom, suspended materials, or plants and animals. Apart from these extraneous factors, water often has an intrinsic colour derived from its chemical contents. The pure colour of blue water is a result of blue light scattering by water molecules. Iron gives water a yellow hue. A green colour is usually associated with high calcium carbonate content. Humic materials make water colour dark brown. Colour of water also influences the productivity of aquatic bodies.         

4.      Turbidity: Degree of opaqueness developed in water by means of suspended particulate matter is known as turbidity. Substances like humus, silt, organic detritus, colloidal matter, plants and animals brought into lake from outside are called as allochthonous. Substances which are produced within lake and produce turbidity are called as autochthonous. The turbidity may be temporary caused by rains, flood etc., or perennial based on the nature of the basin and continuous wave and mind action.                                                                                   

5.      Buoyancy: Buoyancy depends upon the density and temperature of the water. Water becomes denser and viscous at low temperature and gives greater buoyancy. Aquatic animals are slightly heavier than water and these animals tend to sink in less dense water. Buoyancy of water varies with seasonal changes. When water has greater buoyancy, animals have compact bodies, but when the buoyancy is less, animals develop organs which help them in flotation or impede sinking.

6.      Density: The density of large water bodies, lakes and rivers varies at different places and also at different times. These differences in the water density are due to variation in temperature and salt contents of the water. There is a linear increase in water density with increase in dissolved substances of salts. The density changes mere quickly at higher temperatures than at lower ones.                                

7.      Viscosity: Viscosity of water is one hundred times greater than that of air. Viscosity is cause of the frictional resistance which water offers to the moving organisms. The magnitude of viscosity function is proportional to the extent of surface of animal body which is in contact with water, the speed of movement of animal and to temperature.                                                                            

8.      Surface tension: The surface tension acts at the water-air interface and develops a biotope. Many plants and animals and their parts are affected by surface tension in many ways, depending upon whether   parts of animal and plants are wettable or not.                                                                                                               

9.      Water movement: Water movement plays a vital role in shaping the biocoenosis, because of its effect on the substratum. When the movement is vigorous it will carry away the finer particles leaving only stones. Animals that depend on the current to bring food, usually select an optimum speed. Some animals desire a current of certain speed to supply them the oxygen they require.                    

FRESHWATER ZONATION

Lakes and ponds are zoned, primarily on the basis of water depth and type of vegetation that will appear over the course of time in freshwater areas. Freshwater areas have been classified into following zones:                                              

1.      Supralittoral zone: It lies just above the edge of standing water in freshwater pools. Usually this zone is not submerged and is exposed to wave action and splash along the margins of the larger ponds and lakes during windy periods.

2.      Littoral zone: It is a shallow water region near the coast and possesses rooted vegetations. It extends from the water's edge to a depth of about 6 meters. All the rooted hydrophytes and some free swimming fauna are confined to this zone.

3.      Limnetic zone: This is the open water zone reaching up to the depth of effective light penetration. It extends up to 10 meters from water surface. This is also called sublittoral zone.                                                                                            

4.      Profundal zone: The deepest water zone of ponds and lakes is the profundal zone. In this zone there is no photosynthetic activity and it is characterized by muddy bottom.                                                                                             

5.      Abyssal zone: This zone is found only in deep lakes, since it begins at about 200 meters from the surface. Small ponds have little vertical stratification, and in them usually limnetic and profoundal zones are not found. Streams, rivers, brooks and creeks lack the well-defined zonation. Only two zones – a rapid or riffle zone and a pool zone may be recognized. The rapid or riffle zone are shallow water zones with rapid water flow. This zone serves a very ideal environment for many insect larvae, attached algae and some snails. Pool zones are generally numerous along older rivers. The current in pool zone is extremely slow or practically non-existent. The substrate in this zone is fine sand, silt or clay, most suited for burrowing type of animals.                                                                            

CLASSIFICATION OF FRESHWATER HABITATS

Generally freshwater habitats fall into two categories, namely---

1. Lentic (lenis, calm) habitats characterized by standing water, e.g., pond, lake and marsh.

2. Lotic (lotus, washed) habitats having running water, e.g., spring, stream or river.

In nature these two habitats are not sharply differentiated from each other and sometimes form intermediate habitats. It might be caused due to erosion of the soil and the activities of organisms (including man), resulting in the development of different graded habitats.                                                                               

MANAGEMENT OBJECTIVES

The broad objectives of activities under crocodile project were as follows:

1. To protect the remaining population of crocodilians in their natural habitat by creating sanctuaries.

2. To rebuild natural population quickly through 'grow and release' or 'rear and release' technique involving the following phases of operation:

(a) Collection of eggs from natural nests as soon as these were laid.

(b) Incubation of these eggs under ideal temperature and humidity maintained in artificial hatcheries.

(c) Hatching and rearing the young crocodilians in ideal captive-husbandry conditions.

(d) Marking and releasing young crocodiles in protected areas, and

(e) Assessing the result of release along with protection of the released crocodiles.

3. To promote captive breeding.

4. To take-up research to improve management. Some of the major research activities have been in the following directions.

(a) Interpretation of various types of data collected during survey and census.

(b) Determination of parameters for maximum success in egg collection, egg incubation, hatching, rearing and release, including husbandry aspects on feeding, food conversion and growth.

(c) Study of habitat features and population structure.

(d) Study of behavioural biology including reproduction, thermo-regulation, feeding, water-orientation, locomotion etc.

5. To build up a level of trained personnel for better continuity of the project through training imparted at project-sites and through the (erstwhile) Central Crocodile Breeding and Management Training Institute, Hyderabad.              

6. To involve the local people in the project intimately through,

(a) The development of a strong level of acceptance of the project by the people, by locating the projects in rural areas where people could both see and participate in the entire programme.                                                                                

(b) Protecting the immediate and long-term interests of fishermen who live within the sanctuaries, and whose livelihood depends on fishing, through, if necessary, providing an alternative source of income that are not detrimental to the conservation aims.                                                                                         

(c) Extending the conservation programme to village-level, commercial crocodile farming, so that people can earn an income from conserving crocodiles and their habitats.                                                                                                        

PONDS

Ponds are small aquatic bodies of shallow standing water and are generally characterized by relatively quiet waters and abundant vegetation. Ponds may be found in any region of adequate rainfall. In ponds water movement is minimum. Temperature shows diurnal and seasonal changes from place to place. Some ponds have very clear and transparent water, whereas others have muddy water, and between these two extremes all possible intergrades exist. The amount of dissolved carbon dioxide and oxygen in ponds depend mainly upon the nature of bottom. In ponds the stratification is of very minor importance. The littoral zone is relatively larger where-as the sub-littoral and profundal zones are very small or absent.                                                                                                         

TYPES OF PONDS

On the basis of origin ponds are of three types:

1. Ponds derived from large lakes.

2. Ponds which never had any connection with the lakes and which have been very small from the very beginning.

3. Artificial ponds---by human activities.

On the basis of seasonality ponds may be classified as temporary ponds and permanent ponds.

Temporary ponds: In temporary ponds water is present only at certain seasons of the year while at other times they are dry. They are further classified as follows:

(a) Verbal ponds

(b) Vernal autumnal ponds

(c) Aestival ponds

Verbal ponds exist only in spring season, whereas vernal autumnal ponds exist during spring, and dry in summer, but are again refilled in autumn. In aestival ponds water is present throughout the year but it freezes in winter.                

Permanent ponds: In permanent ponds water is present throughout the year. Organisms present in these ponds are not threatened by conditions such as dessication and drying up of waters.                                                                  

LAKES

FORMATION OF LAKES

Lakes are formed either due to glacial action or through rocks underneath the soil being dissolved away with subsequent sinking of the surface, or due to blocking of a valley by a land lide in which large quantity of water gets accumulated. Each of these possibilities produces lakes differing in their characteristics and to a certain extent flora and fauns found in them.                                                           

1. Tectonic lakes: Sometimes, by means of earth's crust shifts, a fissure is formed or pieces of land get sunk and such basins get filled with rain water and form a lake which is known as tectonic lake.                                                                

2. Crater lakes: This type of lake is produced due to volcanic activity and usually is circular in outline with considerable depth.                                                   

3. Land elevation lakes: Sometimes lake is formed by elevation of land, cutting arms of the sea. At present the Kumaon lakes in U.P. furnish examples of formation of lake basins due to landslide.                                                       

4. Glacial lakes: These are formed as a result of the glacial action in which the icebergs move into existing valleys and fill up the hollow areas of the earth. When a glacier melts deep lakes develop in such valleys. Surrounded by steep sides, such lake basins are common in the Northern hemisphere.                               

Following glacial lakes are formed by:

(a) Substrate excavation: Pongong valley in Kashmir.

(b) Deposition of moraines and debris: Wular, Dal and Anchar lakes of Kashmir.

(c) actual ice obstruction of the lower end of a mountain valley: Chombu glaciers in Sikkim

5. Solution lakes: These are formed on soluble rock beds. Depressions are produced by local solution of superficial beds. Many small lakes in the limestone tracts of Khasi and Jaintia hills of Assam are believed to be solution lakes.        

6. Ox-bow lakes: These types are formed by the riverine system, found in the middle and lower reaches of the Ganga and Brahmaputra river systems. These are found in Assam, U.P., Bihar and West Bengal.                                              

7. Lakes formed by wind action: These lakes are formed mainly in dry regions and if those are perennial.    

                                                                                   

MARINE AND ESTUARINE ECOLOGY

INTRODUCTION

The marine environment of seas and oceans is large, occupying 70 per cent of the earth's surface. The volume of surface area of marine environment lighted by the sun is small in comparison to the total volume of water involved. This and the dilute solution of nutrients limit production. It is deep and in places nearly more than 6 kilometers. All the seas are interconnected by currents, dominated by waves, influence by tides and characterized by saline water.                                

PHYSICAL CHARACTERISTICS OF MARINE ENVIRONMENT

In the marine environment, the most important physical factors which influence marine life are as follows:

1. Temperature   2. Light     3. Pressure    4. Tide       5. Currents     6. Waves

1. Temperature: More than any other physical factor of the marine environment, temperature controls growth, reproduction, shape of body and geographical distribution. Variation of temperature in the sea is small with respect to day, season and latitude.

2. Light: Sea water has an incredible capacity to absorb solar radiation, and no part of the sun's radiation reaches beyond 1700 metres. With respect to the presence or absence of solar light, the sea is vertically divisible into three zones. Euphotic zone, Dysphotic zone, Aphotic zone.                                                  

3. Pressure:  The atmospheric pressure at sea level is taken as one atmosphere. For each 10 metres of depth, the pressure increases by one atmosphere.                

4. Tides (currents and waves): The Sea is described as 'restless'. This is indeed true. Though this restlessness may often assume diabolic proportions and cause considerable destruction of life and property, it is this restlessness which makes the whole sea habitable. Waves, currents and tides are the regular features of the sea water. All these phenomena are controlled by winds, cosmic forces and varying water densities.     

                                                                           

CLASSIFICATION OF MARINE ENVIRONMENT

In 1957, Hedgpeth gave a scheme for the classification of marine environment which is widely accepted. Accordingly a sea ha two major environments:

1. Pelagic (open sea water)

2. Benthic (bottom)

1. Pelagic zone: It includes the entire water mass of an ocean. It is arbitrarily divided into two major sub-divisions:

(a) Neritic zone: Consisting of the shallow water of the continental shelf.

(b) Oceanic zone: It includes the deep waters beyond the edge of continental shelf. This zone has been further divided into four subzones:

(i) Epipelagic zone

(ii) Mesopelagic zone

(iii) Bathypelagic zone

(iv) Abyssopelagic zone

(i) Epipelagic zone: This zone extends vertically downwards from the surface to about 200 metres. Here sharp gradients of illumination and temperature occur, between the surface and the deeper levels.                                                     

(ii) Mesopelagic zone: It extends beyond 200 metres to a depth of about 1000 metres. Very little light penetrates here, and the temperature gradient is more even and gradual without much seasonal variation.                                                

(iii) Bathypelagic zone: This zone extends from 1000metres to about 4000metres. Here darkness is virtually complete except for bioluminescence, temperature is low and water pressure in the depths of the sea increases by one atmosphere for every descent of 10 metres.                                                                                

(iv) Abyssopelagic zone: It extends beyond 4000 metres to the depth of the sea.

2. Benthic zones: The sea bottom and the sea shore together make up the benthic division, which has the following zones:                                                         

(a) Supralittoral zone: Which is the beach down to the edge of sea where there are tides, the lower boundry of the supralittoral zone is the high tide mark.           

(b) Littoral zone: The area between upper and lower tide level and therefore is also called as intertidal zone.                                                                          

(c) Eulittoral zone: From the low tide level to a depth of about 50 metres, characterized by the presence of attached plants.                                             

(d) Sub-littoral zone: From the 50 metres to the edge of continental shelf. It is further divided into inner and outer sublittoral. The inner sublittoral is distinguished from the outer by the presence of attached algae upon the former.   

(e) Bathyal zone: Occurs on the continental slope, where the bottom of the ocean descends rapidly about 200 metres down to 3000-4000 metres.                          

(f) Abyssal zone: From 4000 metres depth to approximately 6000 metres, where temperature is never above 40 C                                                                        

(g) Hadal zone: In the great trenches of the ocean, where depths may be as great as 10,000 metres, the benthic zone is called hadal zone. This zone forms a distinct habitat.                                                                                                         

STRATIFICATION OF MARINE ENVIRONMENT

The upper layers of ocean water exhibit a stratification of temperature and salinity. Depths below 300 mts. Are usually thermally stable. In high and low latitudes temperatures remain fairly constant throughout the year. In middle latitudes temperatures vary with the season, associated with climatic changes. In summer the surface waters become warmer and lighter, forming a temporary seasonal thermo cline. In subtropical regions the surface waters are constantly heated, developing a marked permanent thermocline.                   

MARINE COMMUNITIES

Distribution of marine communities depends on their responses to current, temperature and physical barriers. Their local distribution is affected by waves and tides, depth, salinity and type of bottom.

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Unit I

1.1 Understanding Our Environment

            Human actions are having widespread impacts on our world and the other organisms with which we share it.  Science can help us understand both how things work and how we can make our understand both how things work and how we can make our environment safer, more comfortable, and more enduring.  The knowledge being gained by scientists if fundamental to our ability to manage the earth’s resources in a sustainable manner.  Environmental scientists work on many problems that critically affect our well-being in many ways.  Because of the significance of its findings, an understanding of environmental science. 

            One is the natural world of plants, animals, solids, air and water that preceded us by billions of years and of which we are a part.  The other is the world of social institutions and artifacts that we create for ourselves using science, technology, and political organization.  Environment can be defined as

1. The circumstances and conditions that surround an organism or a group of organisms
2. The social and cultural conditions that affect an individual or a community.

Since humans inhabit the natural world as well as the “built” or technological, social and cultural world, all constitute important parts of our environment

Environment science is the systematic study of our environment and our place in it.  a relatively new field, environmental science is highly interdisciplinary.  It integrates information from biology, chemistry, geography, agriculture and many other fields.  To apply this information to improve the ways are treat our world, environmental scientist  also incorporate knowledge of social organization, politics and the humanities.  In other worlds, environmental sciences inclusive and holistic.

            Criteria for environmental literacy have been suggested by the National Environmental Education Advancement Project in Wisconsin.  These criteria include awareness and appreciation of the natural and built environment, knowledge of natural systems and ecological concepts, understanding of current environmental issues and ability to use analytical and problem-solving skills on environmental issues.

1.2 Brief History of Conservation and Environmentalism

            The conservation history is divided the environmental activism into at least four distinct stages

1. Pragmatic resource conservation
2. Moral and aesthetic nature preservation
3. A growing concern about health and ecological damage caused by pollution
4. Global environmental citizenship

Pragmatic resource conservation

            Many historians’ consider the publication Man and Nature in 1864 by geographer George Perkings Marsh as the wellspring of environmental protection in North America.  Marsh observed the damage caused by excessive grazing by goats and sheep and by the deforestation of steep hillsides.   

The basis or Roosevelt’s and Pinchot’s was Pragmatic Utilitarian conservation.  They gave voice to saved forest “not because they are beautiful or because they shelter wild creatures of the wilderness, but only to provide homes and jobs for people.  “Resources should be used “for the greatest good, for the greatest number, for the longest time.  “There has been a fundamental misconception, “Pinchot says, “that conservation means nothing but husbanding of resources for future generations.  Nothing could be further from the truth.  The first principle of conservation is development and use of the natural resources now existing on this continent for the benefit of the people who live here now.  There may be just as much waste in neglecting he development and use of certain natural resources as there is in their destruction.”  This pragmatic approach still can be seen in the multiple-use policies of the U.S. Forest Service.

Moral and aesthetic nature preservation

            Aesthetic and spiritual values formed the core of philosophy of nature protection.  This outlook has been called biocentric preservation because it emphasizes the fundamental right of other organisms and nature as a whole to exist and to pursue their own interests.  The National Park Service, established in 1916, was first headed by Muir’s disciple, Stephen Mather and has always been oriented toward preservation of nature in its purest state.  It has often been at odds with Pinchots’s utilitarian Forest Service.  The pioneering British plant physiologist Stephen Hales, for instance suggested that conserving green plants preserves rainfall.  His ideas were put into practice in 1764 on the Caribbean island of Tobago, where about 20 percent of the land was marked as “reserved in wood for rains”.

Ecological damage caused by pollution

The undesirable effects of pollution probably have been recognized as long as people have been building smoky fires.  In 1273 king Edward I of England threatened to hang anyone burning coal in London because of the acrid smoke it produced.  In 1661 the English diarist John Evelyn complained about the noxious air pollution caused by coal fires and factories and suggested the sweet-smelling trees be planted to purify city air.

The tremendous expansion of chemical industries during and after World War II added a new set of concerns to the environmental agenda.  Silent spring written by Rachel Carson and published in 1962, awaked the public to the threat of pollution and toxic chemicals to humans as well as other species.  The movement of endangered might be called modern environmentalism because its concerns extended to include both natural resources and environmental pollution.  Among some of other pioneers of this movement were activist David Brower, as scientist Barry commoner.  Earth island institute introduced man of the techniques of environmental lobbying and activism, including litigation, intervention in regulatory hearings, book and calendar publishing and use of mass media or publicity campaigns.  Commoner who was trained as molecular biologist has been a leader in analyzing the links between science, technology and society.  Both activism and research remain hallmarks of the modern environmental movement

Global environmental citizenship

            Photographs of the earth from space provide a powerful icon for the fourth wave of ecological concern which might be called global environmentalism. 

            Every year the World Resources Institute the United Nations Environment program and the World Bank issue Earth Trends a comprehensive assessment of current world environmental conditions.  The most recent version describes many serious environmental and social challenges.  With more than 6.5 billion humans currently, we are adding about 85 million more to the world every year.  While demographers report a transition to slower growth rates in most countries, present trends project a population between 8 and 10 billion by 2050.  The impact of that many people on our natural resources and ecological systems is a serous concern.

            Water may well be the most critical resource in the twenty-first century.  Already at least 1.1 billion people lack access to safe drinking water and twice that many don’t have adequate sanitation.  Polluted water contributes to the death of more than15 million people every year, most of them children under age 5.  About 40 percent of the world population lives in countries  lives in countries where water demands now exceed supplies and the UN projects that by 2025 as many as three-fourths of us could live under similar conditions. Pollution proposed that one third of the worlds oceans be declared marine preserve.

            The life threatening infectious diseases has been reduced sharply in most countries during the past century while life expectancies have nearly doubled on average.  Smallpox has been completely eradicated and polio has been vanquished except in a few countries.  Since 1990 more than 800 million people have gained access to improved water supplies and modern sanitation.  In spite of population growth that added nearly a billion people to the world during the 1990s the number facing food insecurity and chronic hunger during this period actually declined by about 40 million.

            Biologist report that habitat destruction, overexploitation, pollution and introduction of exotic organisms are elimination species at a rate comparable to the great extinction that marked the end of the age of dinosaurs.  The UN Environment programme reports that, over the past centaury more than 800 species have disappeared and at least 10,000 species are now considered threatened.  This includes about half of all primates and freshwater fish together with around 10 percent of all plant species.  Top predators including nearly all the big cats in the world are particularly rare and endangered.  A nationwide survey of the United Kingdom in 2004 found that most bird and butterfly populations had declined between 50 and 75 percent over the previous 20 years.  At least half of the forests existing before the introduction of agriculture have been cleared and much of the diverse old growth on which many species depend for habitat is rapidly being cut and replaced by secondary growth or monoculture. 

            Nature preserves and protected areas have increased dramatically over the past few decades.  In 2006 according to UNESCO there were more than 100,000 parks and nature preserves in the world, representing more than 20 million km² or about 13.5 percent of the worlds land area. The increased speed at which information and technology now flow around the world holds promise to find solutions to environmental dilemmas.

1.3 Human Dimensions of Environmental Science

            The humans live in natural and social worlds and because our technologies have become such dominant forces on the planet environmental science must take human institutions and the human condition into account.  The World Bank estimates that more than 1.4 billion people about one-fifth of the world’s population live in acute poverty with an income.  These poorest of the poor generally lack access to an adequate diet, basic sanitation, education, medical care and essential for human existence.

            Policymakers are becoming aware that eliminating poverty and protecting our common environment are inextricably interlinked because the worlds poorest are both the victims and the agents of environmental degradation.  The poorest people are often forced to meet short term survival needs at the cost of long term sustainability.  Desperate for croplands to feed themselves and their families, many move into virgin forest or cultivate seep, erosion-prone hillside, where soil nutrients are exhausted after only a few years.  World Health Organization Director Gro Harlem Brundtland has defined sustainable development as “meeting the needs of the present without compromising the ability of future generations to meet their own needs.  In these terms development then means progress in human well being that we can extend or prolong over many generations rather than just few years. 

Unit II

2.1  ENVIRONMENTAL SYSTEMS

            Environmental Science seeks to understand systems or networks of interactions among interdependent components and processes or compartments and flows.  Systems can be physical as in the biological and chemical cycles than move nutrients around the world or they can be abstract as in a computer program or a mathematical model.  Some systems are closed or self contained and isolated from outside influences.  Other open in the sense that material, energy or information is exchanged between parts of the system and external sources or sinks.  Solar energy warms the wetland and radiant energy leaves it.  Water enters as rain or snow and leaves via evaporation or runoff.  Nutrients come form the sewage effluent and surface runoff, and are deposited in bottom in sediment, carried away by departing organisms or released into the ocean.  A nuclear submarine traveling under the polar ice cap, on the other hand, is a mostly closed system.  For all practical purposes, nothing enters or leaves the system while it is underway.  Eventually, however, the sub must surface and replenish its supplies.  Few systems can be completely self-contained indefinitely.

            Some of the most important characteristics of a system are the interconnections between parts of the system and the regulatory mechanism that control the characteristic of the system.  Some of these controlling mechanisms are external to the system.  Water level in a pond, for example, is determined mainly by the temperature and rainfall.  The pond itself has very little influence on its won volume.  Some more interesting regulatory controls are internal.  The number of fish in a pond is regulated primarily by food supplies, predation, mortality and reproductive rates.

            Sometimes the system’s output can serve as an input to that same system a circular process know as a feedback loop.  A positive feedback loop uses the output from a process to augment that process.  The output from the speaker becomes an input for the microphone and the interaction between them drives the system ever further in one direction (loudness).  If unchecked positive feedback loops can lead a system to become increasingly unbalanced and unstable.  Negative feedback on the other hand reverses the direction in which a system is moving.  System is in dynamic equilibrium or homeostasis, the tendency of a system to maintain constant or stable internal conditions.

            Feedback mechanism in nature also can exacerbate or moderate interactions at both large and small scale.  In the Arcata marsh, for example, some of the interactions act as positive feedbacks while others are negative.  The metabolic wastes (urea, CO2) produced by fish and other herbivores act as a positive feedback to stimulate plant growth.  If too many herbivores reduce plant biomass below a critical level, there won’t be enough food support the fish biomass, again acting as a negative feedback.  Altogether, these regulatory mechanisms generally maintain a balance between the pond organisms and their environment.

            Disturbances, periodic, destructive events such as fire or floods, are a normal part of many natural systems.  They may even depend on the disturbances.  Floodplains often need periodic floods to replenish soil nutrients and maintain vegetative diversity, prairies depend on fires to recycle nutrients, slow tree growth and reduce built-up undecayed plant litter ponderosa pine forests need regular fires to clear understory vegetation.  When a combination of positive and negative feedbacks allow a system to recover from some external disturbance, we say the system has resilience.

                                                                                    +produces wasteCO2

                                                                              

            Photosynthesis                                    Feeding

                                                   plant biomass                                            Fish biomass

            Plant growth                                           O2

                                                                   

-consumers plant 

                - Blocks sunlight

2.2 ELEMENTS OF LIFE

           

Everything that takes up space and has mass is matter.  Matter exists in three distinct states-solids, liquid and gas-due to differences in arrangement of its constitutive particles.  water, for example can exist as ice (solid), as liquid water or as water vapor (gas).  Under ordinary circumstances, mater is neither created nor destroyed but rather is recycled over and over again.  Some of the molecules that make up your body probably contain atoms that once made up the body of dinosaur and most certainly were part of many smaller prehistoric organisms, as chemical elements are used and reused by living organisms.  Matter is transformed and combined in different ways, but it doesn’t disappear, everything goes somewhere.  These statements paraphrase the physical principle of conservation of matter.

            Matter consists of elements, which are substances that cannot be broken down into simpler forms by ordinary chemical reactions.  Each of the 115 known elements (92 natural, plus 23 created under special conditions) has distinct chemical characteristics.  Just four elements-oxygen, carbon, hydrogen and nitrogen are responsible for more than 96 percent of the mass of most living organisms.

            All elements are composed of atoms, which are the smallest particles that exhibit the characteristics of the element.  Atoms are composed of positively charged protons, negatively charged electrons, and electrically neutral neutrons.  Protons and neutrons, which have approximately the same mass, are clustered in the nucleus in the center of the atom.  Electrons, which are tiny in comparison to the other particles, orbit the nucleus at the speed of light.  Each element has a characteristic number of protons per atom called its atomic number.  The number of neutrons in different atom of the same element can vary slightly.  Thus the atomic mass, which is the sum of the protons and neutrons in each nucleus, also can vary.  We call forms of a single element that differ in atomic mass isotopes.

Chemical bonds hold molecules together

            Atoms often join to form compounds, or substances composed of different kinds of atoms.  A pair or group of atoms that can exist as a single unit is known as a molecule.

Some elements commonly occur as molecules such as molecular oxygen or molecular nitrogen and some compounds can exist as molecules such as glucose.  In contrast to these molecules, sodium chloride is a compound that cannot exist as a single pair of atoms.  Others such as proteins and nucleic acids can include millions or even billions of atoms.

            When ions with opposite charges form a compound the electrical attraction holding them together is an ionic bond sometimes atoms form bonds by sharing a single electrons.  When atoms gives up one or more electrons we say it is oxidized and atoms gains electrons we say it is reduced chemical reactions necessary for life involve oxidation and reduction.  Breaking bonds requires energy while forming bonds generally release of energy.  Generally some energy input is needed to initiate these reactions.  In your fireplace a match might provide the needed activation energy.

Electrical charge is an important chemical characteristic

            Atoms frequently gain or lose electrons, acquiring a negative or positive electrical charge.  Charged atoms are called ions.  Negatively charged ions are anions.  Positively charged ions are cations.  Substances that readily give up hydrogen ions in water are known as acids.  

2.3 ENERGY

            If matter is the material of which things are made, energy provides the force to hold structures together, tear them apart and move them from one place to another.  In this section we will look at some fundamental characteristics of these components of our world.

Energy occurs in different types of qualities

            Energy is the ability to do work such as moving matter over a distance or causing a heat transfer between two objects at different temperatures.  Energy can take many different forms.  Heat, light, electricity and chemical energy are examples that e all experience.  The energy contained in moving objects is called kinetic energy.  A rock rolling down a hill the wind blowing through the trees water flowing over a dam or electrons speeding around the nucleus of a atom are all examples of kinetic energy.  Potential energy is stored energy that is latent but available for use.  A rock poised at the top of a hill and water stored behind a dam are examples of potential energy.  Chemical energy stored in the food that you eat and the gasoline that you put into your car are also examples of potential energy that can be released to do useful work.

Thermodynamics regulates energy transfers

Atoms and molecules cycle endlessly through organisms and their environment but energy flows in a one-way path.  A constant supply of energy nearly all of it from the sun is needed to keep biological processes running.

            The study of thermodynamics deals with how energy is transferred in natural processes.  More specifically it deals with the rages of flow and the transformation of energy from one form or quality to another.  Thermodynamics is a complex quantitative discipline but you don’t need a great deal of math to understand some of the broad principles that shape our world and our lives.

            The first law of thermodynamics states that energy is conserved that is it is neither created nor destroyed under normal conditions.  Energy may be transformed for example from the energy in a chemical bond to heat energy but the total amount does not change.

            The second law of thermodynamics states that with each successive energy transfer or transformation in a system, less energy is available to do work.  That is energy is degraded to lover quality forms or it dissipates and is lost as it is used.  When you drive a car for example the chemical energy tends to increase in all natural systems.  Consequently, there is always less useful energy available when you finish a process than there was before started.  Because of this loss, everything in the universe tends to all apart, slow down, and get more disorganized.

            Organisms are highly organized both structurally and metabolically.  Constant care and maintenance is required to keep up this organization and a continual supply of energy is required to maintain these processes.  Every time some energy is used by a cell to do work some of that energy is dissipated or lost as heat.   If cellular energy supplies are interrupted or depleted, the result sooner or later is death.

2.4 ENERGY OF LIFE

            All plants and animals living on the earth’s surfaces, the sun is the ultimate energy sources, but for organisms living deep in the earth’s crust or at the bottom of the oceans, where sunlight is unavailable chemicals derived from rocks provide alternate energy sources.  We’ll consider this alternate energy path way first because it seems to be more ancient.  Before green plants existed, we believed the ancient bacteria-like cells probably lived by processing chemicals in hot springs.

Extremophiles live in severe conditions

            The deep ocean floor was believed to be a biological desert.  Cold, dark subject to crushing pressures and without any known energy supply it was a place where scientists thought nothing could survive.  Undersea explorations in the 1970’s however revealed dense colonies of animals blind shrimp, giant tube worms, strange crabs and bizarre boiling hot, mineral-laden water  bubbles up through cracks in the earth’s crust.  But how were these organisms getting energy through chemosynthesis, process in which inorganic chemicals such as hydrogen sulfide or hydrogen gas serve as an energy source for synthesis of organic molecules.

            Deep-sea explorations of areas without thermal vents also have found abundant life.  The deepest of these species make methane from gaseous hydrogen and carbon dioxide derived from rocks.  Other species oxidize methane using sulfur to create hydrogen sulfide which is consumed by bacteria the serve as a food source for more complex organisms such as tubeworms.  The total amount of methane made by these microbes is probably greater than all the known reserves of coal, gas and oil.  If we could safely extract the huge supplies of methane hydrate in ocean sediments, it could supply our energy needs for hundreds of years.  Of greater immediate importance is that if methane eating microbes weren’t intercepting the methane produced by their neighbors, more than 300 million tons per year of this potent greenhouse gas would probably bubbling to the surface.

Green plants get energy from the sun

            Our sun is a star, a fiery all of exploding hydrogen gas.  Its thermonuclear reactions emit powerful forms of radiation, including potentially deadly ultraviolet and nuclear radiation yet life here is nurtured y and dependent upon this searing energy source.  Solar energy is essential to life for two main reasons.

            The sun provides warmth.  Most organisms survive within a relatively narrow temperature range.  In fact each species has its own range of temperatures within which it can function normally.  At high temperatures bimolecular begin to break down or become distorted and nonfunctional.  At low temperatures some chemical reactions of metabolism occur too slowly to enable organisms to grow and reproduce.   Other planets in our solar system are either too hot or too cold to support life as we know it.  The earth’s water and atmosphere help to moderate, maintain and distribute the sun’s heat.

            Second, nearly all organisms on the earth’s surface organisms depend on solar radiation for life-sustaining energy, which is captured by green plants, algae and some bacteria in a process called photosynthesis.  Photosynthesis converts radiant energy into useful high quality chemical energy in the bonds the hold together organic molecules.

Photosynthesis

            The connection is energy, of course. For the apple tree to combine inorganic raw materials such as carbon dioxide and water into organic compounds such as sugar and starch, it needs a source of energy. The rays of sunlight, as they fall on the leaves of the apple tree, provide that energy. The process of making this food, by using light as the source of energy, is photosynthesis. All green plants are photosynthetic autotrophs.

The first photosynthetic organisms probably evolved about 3,500 million years ago, early in the evolutionary history of life, when all forms of life on Earth were microorganisms and the atmosphere had much more carbon dioxide. They most likely used hydrogen or hydrogen sulfide as sources of electrons, rather than water.  Cyanobacteria appeared later, around 3,000 million years ago, and drastically changed the Earth when they began to oxygenate the atmosphere, beginning about 2,400 million years ago. This new atmosphere allowed the evolution of complex life such as protists. Eventually, no later than a billion years ago, one of these protists formed a symbiotic relationship with a cyanobacterium, producing the ancestor of many plants and algae. The chloroplasts in modern plants are the descendants of these ancient symbiotic cyanobacteria.

2.5 FROM SPECIES TO ECOSYSTEM

            Cellular and molecular biologist study life processes at the microscopic level, ecologist study interactions at the species, population, biotic community or ecosystem level.  In Latin species literally means kind.  In biology, species refers to all organisms of the same kind that are genetically similar enough to breed in nature and produce live, fertile offspring.  There are several qualifications and some important exceptions to this definition of species, but for our purposes this is a useful working definition.

Organisms occur in populations, communities and ecosystems

            A population consists of all the members of a species living in a given area at the same time.  Population growth and dynamics.  All of the populations or organisms living and interacting in a particular area make up a biological community.  An ecological system or ecosystem, is composed of a biological community and its physical environment.

Foodchain And  Foodweb

Food chain shows how each living thing gets its food. Some animals eat plants and some animals eat other animals. For example, a simple food chain links the trees & shrubs, the giraffes (that eat trees & shrubs), and the lions (that eat the giraffes). Each link in this chain is food for the next link. A food chain always starts with plant life and ends with an animal. Plants are called producers because they are able to use light energy from the Sun to produce food (sugar) from carbon dioxide and water. Animals cannot make their own food so they must eat plants and/or other animals. They are called consumers. There are three groups of consumers.  These decomposers speed up the decaying process that releases mineral salts back into the food chain for absorption by palnt as nutirents

Animals that eat ONLY PLANTS are called herbivores (or primary consumers).
Animals that eat OTHER ANIMALS are called carnivores.

Animals and people who eat BOTH animals and plants are called omnivores.

Food web

The pioneering animal ecologist Charles Elton (1927) introduced the concept of the food web (which he called food cycle) to general ecological science. As he described it: "The herbivores are usually preyed upon by carnivores, which get the energy of the sunlight at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as 'food-chains', and to all the food chains in a community as the 'food-cycle.'"

A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or "primary producer" tropic level, all herbivores comprise the second or "primary consumer" trophic level, and carnivores that eat herbivores comprise the third or "secondary consumer" trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.

Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from phytoplankton to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels.

A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of ecosystems, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by thermodynamics. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs

The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time.

Decomposers are an assemblage of small organisms, including invertebrates, fungi, and bacteria, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.

2.6 BIOGEOCHEMICAL CYCLES AND LIFE PROCESSES.

Introduction

The patterns of cycling nutrients in the biosphere involves both biotic and abiotic chemical reactions. Understanding the biogeochemical cycle of any biologically important element requires the knowledge of chemical processes that operate in the biosphere, lithosphere, atmosphere, and hydrosphere.

The biogeochemical cycles of all elements used by life have both an organic and an inorganic phase. For most of these nutrients, how efficiently these elements cycle from the organic component back to the inorganic reserviors determines how much is available to organisms over the short term. This cycling involves the decomposition of organic matter back into inorganic nutrients. The major reservoirs for all metabolically important elements are found either in the atmosphere, lithosphere (mainly rock, soil and other weathered sediments) or hydrosphere. Flow from these reservoirs to the organic phase is generally slower than the cycling of nutrients through organic matter decomposition.

 Nutrients Essential for Life

Living organisms require the availability of about 20 to 30 chemical elements for the various of metabolic processes that take place in their bodies. Some products of this metabolism require relatively few nutrients for their production. For example, carbohydrates are photosynthesized from just water and carbon dioxide. Some organic substances, like amino acids and proteins, are more complex in their chemical make up and therefore require a number of different nutrients.

The types of nutrient needed by life is often categorized into two groups. Elements required in relatively large amounts are generally referred to as macronutrients. Macronutrients that constitute more than 1% each of dry weight include carbon, oxygen, hydrogen, nitrogen, and phosphorus. Macronutrients that constitute 0.2 to 1% of dry organic weight include sulfur, chlorine, potassium, sodium, calcium, magnesium, iron, and copper.

Nutrients needed in trace amounts are generally called micronutrients. These elements often constitute less than 0.2% of dry organic matter. Some common micronutrients required by living organisms include aluminum, boron, bromine, chromium, cobalt, fluorine, gallium, iodine, manganese, molybdenum, selenium, silicon, strontium, tin, titanium, vanadium, and zinc.

A biogeochemical cycle or inorganic-organic cycle is a circulating or repeatable pathway by which both a chemical element or a molecule moves through both biotic (“bio-”) and abiotic ("geo-") compartments of an ecosystem. In effect, an element is chemically recycled, although in some cycles there may be places (called "sinks") where the element accumulates and is held for a long period of time. In considering a specific biogeochemical cycle, we focus on a particular element and how that element participates in chemical reactions, moving between various molecular configurations. Of the 90-odd elements known to occur in nature, some 30 or 40 are thought to be required by living organisms. We will be considering only a few of these, mainly those utilized in fairly large quantities by living organisms. The principal elements of life are carbon, hydrogen, oxygen, and nitrogen. However, a number of others are certainly important to understand as well, notably phosphorus and sulfur. Some "non-essential" elements participate in biogeochemical cycles, entering organism tissues because of chemical similarity to essential elements. For example, strontium can behave like calcium in the body.

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UNIT - III

3.1 SPECIES POPULATIONS, INTERACTIONS AND COMMUNITIES

 Species

Species are the different kinds of organisms found on the Earth. A more exact definition of species is a group of interbreeding organisms that do not ordinarily breed with members of other groups. If a species interbreeds freely with other species, it would no longer be a distinctive kind of organism. This definition works well with animals. However, in some plant species fertile crossings can take place among morphologically and physiologically different kinds of vegetation. In this situation, the definition of species given here is not appropriate.

 Populations

A population comprises all the individuals of a given species in a specific area or region at a certain time. Its significance is more than that of a number of individuals because not all individuals are identical. Populations contain genetic variation within themselves and between other populations. Even fundamental genetic characteristics such as hair color or size may differ slightly from individual to individual. More importantly, not all members of the population are equal in their ability to survive and reproduce.

Communities

Community refers to all the populations in a specific area or region at a certain time. Its structure involves many types of interactions among species. Some of these involve the acquisition and use of food, space, or other environmental resources. Others involve nutrient cycling through all members of the community and mutual regulation of population sizes. In all of these cases, the structured interactions of populations lead to situations in which individuals are thrown into life or death struggles.

In general, ecologists believe that a community that has a high diversity is more complex and stable than a community that has a low diversity. This theory is founded on the observation that the food webs of communities of high diversity are more interconnected. Greater interconnectivity causes these systems to be more resilient to disturbance. If a species is removed, those species that relied on it for food have the option to switch to many other species that occupy a similar role in that ecosystem. In a low diversity ecosystem, possible substitutes for food may be non-existent or limited in abundance.

Species Interaction

• Predation-In a predator-prey relationship, the predator feeds on the prey. It is a short-lived relationship, with the prey being killed. For e.g.- cheetah feeds upon deer.

• Parasitism-In a parasite-host relationship, the parasite usually lives upon or inside the host. The two are connected by a long, painful relationship. Parasitism and predation are different in respect to the fact that whereas a prey suffers an almost instantaneous death, a host suffers perpetuating pain, often not resulting in death. For e.g. - tapeworms

• Commensalism - In commensalism, one organism derives benefits from its relationship with another. The other organism is not affected in any way by the relationship.

• Mutualism - In a mutualistic relationship, both participating organisms derive benefits from each other. This results in a steady, long relationship.

• Competition - Two different species interact when competing for the same resources: prey, habitat, water, etc.

3.2 SPECIES DIVERSITY ARIES

A more important question to environmental scientist is, what are the mechanism that promote the great variety of species on earth and that determine which species will survive in one environment but not another? In this section you will come understand (1) concepts behind the theory of speciation by means of natural selection and adaptation (evolution); (2) the characteristics of species that make some of them weedy and others endangered; and (3) the limitations species face in their environments and implications for their survival.

Natural selection and adaptation modify species

Adaptation, the acquisition of traits that allows a species to survive in its environment, is one of the most important concepts in biology. We use the term adapt in two ways. An individual’s organism can respond immediately to a changing environment in a process called environment in a process called acclimation. e.g if you keep a houseplant indoors all winter and then put it out in full sunlight in the spring, the leaves become damaged. If the damaged isn’t severe, your planet may grow new leaves with thicker cuticles and denser pigments. After another winter inside, it will still get sun-scaled in the following spring. The leaf changes are not permanent and cannot be passed on to offspring, or even carried over from the previous year. Although the capacity to acclimate is inherited, houseplants in each generation must develop their own protective leaf epidermis.   

Another type of adaptation affects the population consisting of many individuals. Genetic traits are passed from generation to generation and allow species to live more successfully in its environment. This process of adaptation to environment is explained by the theory of evolution. It was simultaneously proposed by Charles Darwin (1809- 1882) based on his studies in the Galapagos Islands and elsewhere, and by Alfred Russel Wallace (1823-1913), who investigated the species of the Malay Archipelago. The basic idea of evolution is that species change over generation because individuals compete for scarce resources. Better competitors in a population survive-they have greater reproductive potential or fitness – and their offspring inherit the beneficial traits. Over generations, those traits become common in a population. The process of better- selected individuals passing their traits to the next generation is called natural selection. Every organism has a dizzying array of genetic diversity in its DNA. Exposure to ionizing radiation and toxic materials, and random recombination and mistakes in replication of DNA strands during reproduction are the main causes of genetic mutations. Sometimes a single mutation has a large effect, but evolutionary change is mostly brought about by many mutations accumulating over time. Most mutations have no effect on fitness, and many actually have a negative effect. During the course of species’ life span- a million or more years – some mutations are thought to have given those individuals an advantage under the selection pressures of their environment at that time. The result is a species population that differs from those of numerous preceding generations.  

All species live within limits

Environmental factors exert selection pressure and influence the fitness of individuals and their offspring. For this reason, species are limits in where they can live. Limitations include the following: (1) physiological stress due to inappropriate levels of some critical environmental factor, such as moisture, light, temperature, pH or specific nutrients; (2) competition with other species; (3) predation, including parasitism and disease; and (4) luck. In some cases, the individuals of a population that survive environmental catastrophes or find their way to new habitat, where they start to the new population, may simply be lucky rather than fit than their contemporaries. An organism’s physiology and behavior allow it to survive only in certain environments. Temperature, moisture level, nutrient supply, soil and water chemistry, living space, and other environmental factors must be at appropriate levels for organisms to persist. In 1840, the chemist Justus von Liebig proposed that the single factor in shortest supply relative to demand is the critical factor determining where a species lives. e.g  the giant saguaro cactus (Carnegiea gigantea), which grows in the dry, hot Sonoran desert of south Arizona and northern Mexico, offers an example. Saguaros are extremely sensitive to freezing temperatures. A single winter night with temperature below freezing for 12 or more hours kills growing tips on the branches, preventing further development. Thus the northern edge of the saguaro’s range corresponds to a zone where freezing temperature last less than half a day at any time.

Ecologist Victor Shelford (1877-1968) later expended Liebig’s principle by stating that each environmental factor has both minimum and maximum levels, called tolerance limits, beyond which a particular species cannot survive or unable to reproduce. In some species, tolerance limits affect the distribution of young differently than adults. The desert pupfish, for instance, lives in small, isolated population in warm spring in northern Sonoran desert. Adult pupfish can survive temperatures between 0 and 42 C and tolerance an equally wide range of salt concentrations. Egg and juvenile fish, however, can survive only between 20 and 30 C and are killed by high salt levels. Reproduction, therefore, is limited to a small part of the range of the adult fish. Sometimes the requirements and tolerance of species are useful indicators of specific environmental characteristics.

The ecological niche is a species’ role and environment 

Habitat describes the place or set of environmental conditions in which a particular organism lives. a more functional term, ecological niche, describes either the role played by a species in a biological community or the total  set of environmental factors that determine a species distribution. The concept of niche was first defined in 1927 by the British ecologist Charles Elton (1900- 1991). To Elton, each species had a role in a community of species, and the niche defined its way of obtaining food, the relationship it had with other species, and the service it provided to its community. e.g for the generalist, like the brown rat, the ecologist niche is board. In other words, a generalist has a wide range of tolerance for many environmental factors.  

Over time, the niches change as species develop new strategies to exploit resources. Species of greater intelligence or complex social structures, such as elephants, chimpanzees, and dolphins, learn from their social group how to behave and invent new ways of doing things when presented with novel opportunities or challenges. In effect, they alter their ecological niche by passing on culture behavior from one generation to the next. Most organisms however are restricted to their niche by their genetically determined bodies and instinctive behaviors. When two such species compete for limited resources, one eventually gains the large share, while the other finds different habitat, dies out, or experiences a change in its behavior and physiology so that competition is minimized. 

Speciation maintains species diversity

As an interbreeding species population becomes better adapted to its ecological niche, its genetic heritage (including mutations passed from parents to offspring) gives it the potential to change further as circumstances, dictate. In the case of Galapagos finches, evidence from body shape, behavior, and genetic leads to the idea that modern Galapagos finches look, behave, and bear DNA related to an original seed-eating finches species. It is proposed to have blown to the islands from the mainland where a similar species still exists. Today there are 13 distinct species on the islands that differ markedly in appearance, food preferences, and habitat. Fruit eaters have thick, parrot- like bills; seed eaters have heavy, crushing bills; insect eaters have thin, probing beaks to catch their prey. One of the most unusual species is the woodpecker finch, which pecks at tree bark for hidden insects. Lacking the woodpecker’s long tongue, the finch uses a cactus spine as a tool to extract bugs. The development of a new species is called speciation. No one has observed a new species springing into being, but in some organisms, especially plants, it is inferred to occur somewhat frequently. Nevertheless, given the evidence, speciation is a reasonable proposal for how species arise. Speciation may be relatively rapid on millennial timescales (punctuated equilibrium).

For example, after a long period of stability, a new species may arise from parents following the appearance of a new food source, predator, or competitor, or a change in climate. One mechanism of speciation is geographic isolation. This is termed allopatric speciation- species arise non-overlapping geographic locations. The original Galapagos finches were separated from the rest of the population on the mainland, could no longer share genetic material, and become reproductively isolated. The barriers that divided subpopulations are not always physical. For example, two virtually identical tree frogs (Hyla versicolor, H. Chrysoscelis) live in similar habitats of eastern North America but have different matting calls. This is an example for behavioral isolation. This is an example of behavioral isolation. It also happens that one species has twice the chromosomes of the other. This example of sympatric speciation takes place in the same locations as the ancestor species. Fern species and other plants seem prone to sympatric speciation by doubling or quadrupling the chromosome number of their ancestor.

Hyla versicolor                                                Hyla Chrysoscelis

Once isolation is imposed, the two populations being to diverge in genetics and physical characteristics. Genetic drift ensures that DNA of two formerly joined populations eventually diverges; in several generations, traits are lost from a population during the natural course of reproduction. Under more extreme circumstances, a die-off of most members of an isolated population strips much of the variation in traits from the survivors. The cheetah experienced a genetic bottleneck about 10,000 years ago and exists today as virtually identical individuals.

In isolation, selection pressure shape physical, behavioral, and genetic characteristics of individuals, causing population traits to shift over time. e.g individual cockroaches that lack this characteristics are dying out, and as a result, populations of cockroaches with pesticide resistance are developing. A small population in a new location- island, mountaintop, and unique habitat – encounters new environmental conditions that favor some individuals over others. Where a species may have existed but has died out, others arise and contribute to the incredible variety of life- forms seen in nature.  

Taxonomy describes relationships among species

Taxonomy is the study of types of organisms and their relationships. Taxonomic relationships among species are displayed like tree. Botanists, ecologist, and other scientists often use the most specific levels of the tree, genus and species to compose binomials. 

3.3 SPECIES INTERACTIONS SHAPE COMMUNITIES OF SPECIES

The adaptation of environment, determination of ecological niche, and even speciation is affected not just by bodily limits and behavior, but also by competition and predation. Don’t despair. Not all biological interactions are antagonistic, and many, in fact, involve cooperation or at least benign interactions and tolerance. In some cases, different organisms depend on each other to acquire resources. Now we will look at the interactions within and between species that affect their success and shape and biological communities.

Competition leads to resource allocation

            Competition is a type of antagonistic relationship within a biological community. Organisms compete for resources that are in limited supply: energy and matter in usable forms, living space, specific sites to carry out life’s activities. Plants compete for growing space to develop root and shoot systems so that they can absorb and process sunlight, water, and nutrients. Animals compete for living, nesting and feeding sites, and also for mates. Competition among members of the same species is called intraspecific competition, whereas competition between members of different species is called interspecific competition. Recall the competitive exclusion principle as it applies to interspecific competition. Competition shapes a species population and biological community by causing individuals and species to shift their focus from one segment of a resource type to another. Thus, warblers all competing with each other for insect food in New England tend to specialize on different areas of the forest’s trees, reducing or avoiding competition.

            In intraspecific competition, members of the same species compete directly with each other for resources. Several avenues exist to reduce competition in a species population. First, the young of the year disperse. Even plants practice dispersal; seeds are carried by wind, water and passing animals to less crowded conditions away from the parent plants. Second, by exhibiting strong territoriality, many animals force their offspring or trespassing adults out of their vicinity. In this way terrestrial species, which include bears, songbirds, ungulates, and even fish, minimize competition between individuals and generations. The adult and juveniles of these species occupy different ecological niches. For instance, monarch caterpillars munch on milkweed leaves, while metamorphosed butterflies lap nectar. Crabs begin as floating larvae and do not compete with bottom- dwelling adult crabs.    

Predation affects species relationships

All organisms need food to live. Producers make their own food, while consumers eat organic matter created by other organisms. Consumers include herbivores, carnivores, omnivores, scavengers, detritivores, and decomposers. Predation is a powerful but complex influences on species populations in communities. It affected (1) all stages of life cycles of predator and prey species; (3) the evolutionary adjustments in behavior and body characteristics that help prey escape being eaten, and predators more efficiently catch their prey. Predation also interacts with competition. In predator-mediated competition, a superior competitor in a habit builds up a large population than its competing species; predators take note and increase their hunting pressure on the superior species, reducing its abundance and allowing the weaker competitor to increase in number.

Some adaptations help avoid predation

Predator-prey relationship exerts selection pressures that favor evolutionary adaptation. In this world, predators became more efficient and searching and feeding, and prey became more effective at escape and avoidance. Toxic chemicals, body are more, extraordinary speed, and the ability to hide are a few strategies organisms is to protect themselves. The response to prey and vice versa, over tens of thousands of years, produces physical and behavioral changes in a process known as coevolution. Coevolution can be mutually beneficial: many plants and pollinators have form and behaviors that benefit each other. A classic case is that of fruit bats, which pollinate and dispersed seed of fruit-bearing tropical plant.

3.4 THE GROWTH OF SPECIES POPULATION

Many biological organisms can produce unbelievable numbers of offspring if environmental conditions are right. Consider the common house fly (Musca domestica). Each female fly lays 120 eggs in a generation. In 56 days those eggs become mature adults, able to reproduce. In one year with seven generation of flies being born and reproducing, that original fly would be the proud parent of 5.6 trillion offspring. If this rate of reproduction continued for ten years, the entire earth would be covered in several meters of housefly bodies. Luckily housefly reproduction, as for most organisms, is constrained in a variety of ways- scarcity resources, competition, predation, disease, accident. The housefly merely demonstrated the remarkable amplification- the biotic potential- of unrestrained biological reproduction. Population dynamics describes these changes in the number of organisms in a population over time.

Growth without limits is exponential

The growth of the housefly population just described shape when graphed over time. am exponential growth rate is expressed as a constant fraction, or exponent, which is used as a multiplier of the existing population. The mathematical formula for exponential growth is

dN

----  = rN

 dt

that is the change in numbers of individuals (dN) per change in time (dt) equals the rate of growth (r) times the number of individuals in the population (N). The r term is a fraction representing the average individual contribution of population growth. If r is positive, the population is increasing. If r is negative, the population is shrinking. If r is zero, there is no change, and dN/dt= 0. 

3.5  Human Population

Past and present Population Growth

Every second, on average, four or five children are born, somewhere on the earth. In that same second, two other people die. The world population is the total number of living humans on the planet Earth, currently estimated to be 6.97 billion by the United States Census Bureau, as of October 15, 2011. The world population has experienced continuous growth since the end of the Great Famine and Bubonic Plague in 1350, when it was about 370 million. The highest rates of growth—increases above 1.8% per year—were seen briefly during the 1950s, and for a longer period during the 1960s and 1970s. The growth rate peaked at 2.2% in 1963, and had declined to 1.1% by 2009. Annual births peaked at 173 million in the late 1990s, and are now expected to remain constant at their current level of 140 million, while deaths number 57 million per year, and are expected to increase to 80 million per year by 2040. Current projections show a continued increase of population (but a steady decline in the population growth rate), with the global population expected to reach between 7.5 and 10.5 billion by the year 2050.

10 Countries with the largest population

Factors determine the population growth

The highest population growth rates occur in a few “hot spots” in the developing world, such as sub-Saharan Africa and the Middle East, where economics, politics, religion, and civil unrest keep birth rates high and contraceptive use low. In chad and the Democratic Republic of Congo, for example, annual population growth is above 3.2 percent. Less than 10 percent of all couples use any form of birth control, women average more than seven children each, and nearly half the population less than 15 years old. Even fast growth rates occur in Omen and Palestine, where the population doubling time is only 18 years. On the other hand, shrinking population characterize some rich countries. Japan which has 128 million resistances now is expected to shrink about 100 million by 2050.  The world population density map shows human population distribution around the world. Notice the high densities supported by fertile river valleys of the Nile, Ganges, yellow, Yungtze and Rhine Rivers are well watered Costal plains of India, China, and Europe. Historic factors, such as technology diffusion and geopolitical power, also play a role in geographic distribution.  

Fertility various among cultures and at different times

Fecundity is the physical ability to reproduce, while fertility is the actual production of offspring. Those without children may be fecund but not fertile. The most accessible demographic statistic of fertility is usually the crude birth rate, the number of births in a year per thousand persons. It is statistically “crude” in the sense that it is not adjusted for population characteristics, such as the number of women of reproductive age. The total fertility rate is the number of children born to an average woman in a population during her entire reproductive life. Fertility is usually calculated as a birth per women because, in many cases, establishing paternity is difficult. Nevertheless, a few demographers argue that we should pay more attention to birth rates per male because in some cultures men have far more children, on average, than do women. Zero population growth (ZPG) occurs when births plus immigration in population just equal deaths plus emigration. It takes several generation of replacement-level fertility to reach ZPG.

Mortality offsets births

In demographics, however, crude death rates are expressed in terms of the number of deaths per thousand persons in any given year. Countries in Africa where health care and sanitation are limited may have mortality rates of 20 or more per 1,000 people. Wealthier countries generally have mortality rates around 10 per 1,000. The number of deaths in a population is sensitive to the population’s age structure. This is because a rapidly growing country has proportionately more youths and fewer elderly than a more slowly growing country. Declining mortality, not rising fertility, was the primary cause of most population growth in the past 300 years. Crude death rates began falling in Western Europe during the late 1700s.

Life expectancy is rising worldwide

Life span is the oldest age to which a species is known to survive. Although there are many claims in ancient literature of kings living for a thousand years and more, the oldest age that can be certified by written records was that of Jeanne Louise Calment of Arles, France, who was 122 years old at her deaths in 1997. While modern medicine has made it possible for many of us to survive much longer than our ancestors, it doesn’t appear that the maximum life span has increased much at all. Apparently, cells in our bodies have a limited ability to repair damage and produce new components. Sooner or later they simply wear out, and we fall victim to disease, degeneration, accidents, or senility.    

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Unit IV

4.1 BIOMES AND BIODIVERSITY

Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms,  and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a large area creating a typical ecosystem over that area.  The biomes we learned about shelter an astounding variety of living organisms.  From the driest desert to the dripping rainforests, from the highest mountain peaks to the deepest ocean trenches life occurs in a marvelous spectrum of sizes, colors, shapes, life cycles, and interrelationships. .  Biodiversity the variety of living things also makes the world a more beautiful and exciting place to live.  Three kinds so biodiversity are essential to preserve ecological systems and functions

1)      Genetic diversity

2)      Species diversity

3)      Ecological diversity

4.2 TERRESTRIAL BIOMES

            All local environments are unique, it is helpful to understand them in terms of a few general groups with similar climate conditions, growth patterns and vegetation types.  We call these broad types of biological communities biomes. 

            Temperature and precipitation are among the most important determinants in biome distribution on land.  If we know the general temperature range and precipitation level, we change predict what kind of biological community is likely to occur there, in the absence of human disturbance.  Landforms, especially mountains and prevailing winds also influence biological communities.  Temperature and precipitation change with elevation as well as with latitude.  In mountainous regions, temperatures are cooler and precipitation is usually greater at high elevations.  Mountains are cooler and often wetter, than low elevations.  Vertical zonation   is a term applied to vegetation zones defined by altitude.  Moist climates may vary in precipitation rates but evaporation rarely exceeds precipitation. 

Tropical moist forests are warm and wet year-round

           

            The humid tropical regions support one of the most complex and biologically rich biome types in the world. Although there are several kinds of moist tropical forests, all have ample rainfall and uniform temperatures.  Cool cloud forests are found high in the mountains where fog and mist keep vegetation wet all the time.  Tropical rainforests occur where rainfall is abundant more than 200cm per year and temperatures are warm to hot year round.

            The soil of both these tropical moist forest types tends to be thin, acidic and nutrient-poor.  Yet the number of species present can be mind-boggling.  For example the number of insect species   in the canopy of tropical rainforests has been estimated to be in the millions it is estimated that one-half to two thirds of all species of terrestrial plants and insects live in tropical forests.  When the forest is removed for logging, agriculture and mineral extraction the thin soil cannot support continued cropping and cannot resist erosion form the abundant rains and if the clear area is too extensive, it cannot be repopulated by rainforest community.

Tropical seasonal forests have annual dry seasons

           

            Many tropical regions are characterized by distinct wet and dry seasons, although temperatures remain hot year-round.  These areas support tropical seasonal forests drought-tolerant forests that look brown and dormant in the dry season but burst into vivid green during rainy months.  These forests are often called dry tropical forests because they are dry much of the year however there must be some periodic rain to support tree growth.  Many of the trees and shrubs in a seasonal forest are drought deciduous they lose their leaves and cease growing when no water is available.  Seasonal forests are often open woodlands that grade into savannas. 

            Tropical dry forests have typically been more attractive than wet forests for human habitation and have suffered greater degradation.  Clearing a dry forest with fire is relatively easy during the dry season.  Soils of dry forests often have higher nutrient levels and are more agriculturally productive than those of a rainforest.  Finally having fewer insects, parasites and fungal diseases than a wet forest makes a dry or seasonal forest a healthier place for humans to live.

Tropical savannas and grasslands are dry most of the year

            Where there is too little rainfall to support forests we find open grasslands or grassland with sparse tree cover which we call savannas.  Like tropical seasonal forests most tropical savannas and grasslands have a rainy season but generally the rains are les abundant or less dependable than in a forest.  Migratory grazers such as wildebeest, antelope or bison thrive on this new growth.  Grazing pressure from domestic livestock is an important threat to both the plants and animals of tropical grasslands and savanna.

4.3 MARINE ECOSYSTEM

            The biological communities in oceans and seas are poorly understood, but they are probably as diverse and as complex as terrestrial biomes.  Oceans cover nearly three-fourths of the earth’s surface, and they contribute in important, although often unrecognized, ways to terrestrial ecosystems.  Like land-based systems, most marine communities depend on photosynthetic organisms.  Often it is algae or tiny, free-floating photosynthetic plants (phytoplankton) that support a marine food web, rather than the trees and grasses we see on land.  In oceans, photosynthetic activity tends to be greatest near coastlines, where nitrogen, phosphorus and other nutrients wash offshore and fertilize primary producers.  Ocean currents also contribute to the distribution of biological productivity, as they transport nutrients and phytoplankton far from shore

            As plankton, algae, fish and other organisms die, they sink toward the ocean floor.  Deep-ocean ecosystems, consisting of crabs, filter-feeding organisms, strange phosphorescent fish and many other life-forms, often rely on this “marine snow’ as a primary nutrient source.  Surface communities also depend on this material.  Upwelling currents circulate nutrients from the ocean floor back to the surface.  Along the coasts of South America, Africa and Europe, these currents support rich fisheries.

            Vertical stratification is a key feature of aquatic ecosystems.  Light decreases rapidly with depth and communities below the photic zone (light zone, often reaching about 20m deep) must rely on energy sources other than photosynthesis to persist.  Temperature also decreases with depth.  Deep-ocean species often grow slowly in part because metabolism is reduced in cold conditions.  In contrast, warm, bright, near-surface communities, such as coral reefs and estuaries, are among the world’s most biologically productive environments.  Temperature also affects the amount of oxygen and other elements that can be absorbed in water.  Cold water holds abundant oxygen, so productivity is often high in cold oceans, as in the North Atlantic, North Pacific, and Antarctic.

Open ocean communities vary from surface to hadal zone

            Ocean systems can be described by depth and proximity to shore.  In general, benthic communities occur on the bottom and pelagic (from “sea” in Greek) zones are the water column.  The epipelagic zone (epi=on top) has photosynthetic organisms.  Below this are the mesopelagic (meso=medium) and bathypelagic (bathos=deep) zones.  The deepest layers are the abyssal zone (to 4000 m) and hadal zone (deeper than 6,000 m).  Shorelines are known as littoral zones and the area exposed by low tides is known as the intertidal zone.  Often there is a broad, relatively shallow region along a continent’s coast, which may reach a few kilometers or hundreds of kilometers from shore.  This undersea area is the continental shelf.

            The open ocean has long been known as a biological desert, because it has relatively low productivity or biomass production.  Fish and plankton abound in many areas, however, Seamounts or undersea mountain chains and islands, support many commercial fisheries and much newly discovered biodiversity.  Deep-sea thermal vent communities are another remarkable type of marine system that was completely unknown until 1977, when the deep-sea submarine Alvin descended to the deep-ocean floor.  These communities are based on microbes that capture chemical energy, mainly from sulfur compounds released from thermal vents-jets of hot water and minerals on the ocean floor.  Magma below the ocean crust heats these vents. Tube works, mussels and microbes on the vents are adapted to survive both extreme temperatures often above 350°c (700°F) an intense water pressure at depths of 7,000 m (20,000 ft) or more.  Oceanographers have discovered thousand of different types of organisms most of the microscopic in these communities some estimate that the total mass of microbes on the seafloor represents one-third of all biomass on the planet.

Tidal shores support rich, diverse communities

            Coral reefs are among the best-known marine systems, because of their extraordinary biological productivity and their diverse and beautiful organisms.  Reefs are colonies of minute, colonial animals 9”coral polyps”) that live symbiotically with photosynthetic algae.  Calcium-rich coral skeletons shelter the algae and algae nourish the coral animals.  The complex structure of a reef also shelters countless species f fish, worms, crustaceans and other life-forms. 

            Reefs are among the most endangered biological communities.  Sediment form coastal development, farming, sewage or other pollution can reduce water clarity and smother coral.  Destructive fishing practices, including dynamite and cyanide poison, have destroyed many Asian reefs.  Reefs can also be damaged or killed by changes in temperature, by invasive fish, and by diseases.  Coral bleaching, the whitening or reefs due to stress, often followed by coral death, is a growing and spreading problem that worries marine biologists.

            Sea-grass beds, or eel-grass beds, occupy shallow, warm, sandy coastlines.  Like reefs, theses support rich communities of grazers, from snails to turtles to Florida’s manatees.    

            Mangroves are a diverse group of salt-tolerant trees that grow along warm, calm marine coasts around the world.  Growing in shallow, tidal mudflats, mangroves help stabilize shorelines, blunt the force of storms and build land by trapping sediment and organic material.  Coral reefs and sea-grass beds, mangrove forests provide sheltered nurseries for juvenile fish, crabs, shrimp and other marine species on which human economies depend. However, like reefs and sea-grass beds, mangroves have been devastated by human activities.  Estuaries are bays where rivers empty into the sea, mixing fresh water with salt water.  Salt marshes, shallow wetlands flooded regularly or occasionally with seawater, occur on shallow coastlines, including estuaries.  Usually calm, warm and nutrient-rich, estuaries and salt marshes are biologically diverse and productive.  In contrast to the shallow, calm conditions of estuaries, coral reefs and mangroves there are violent, wave-blasted shorelines that support fascinating life-forms in tide pools. Tide pools are depressions in a rocky shoreline that are flooded at high tide but retain some water at low tide. Extreme conditions, with frigid flooding at high tide and hot, desiccating sunshine at low tide, make life impossible for most species.  But the specialized animals and plants that do occur in this rocky intertidal zone astonishingly diverse and beautiful.

4.4 FRESHWATER ECOSYSTEMS

Freshwater environments are far less extensive than marine environments, but they are centers of biodiversity.  Most terrestrial communities rely, to some extent, on freshwater environments.  In deserts, isolated pools, streams, and even underground water systems support astonishing biodiversity as well as provide water to land animals.  

Lakes have open water

            Freshwater lakes, like marine environments, have distinct vertical zones.  Near the surface a sub community of plankton mainly microscopic plants, animals and protists (single-celled organisms, such as amoeba), flat freely in the water column.  Insects such as water striders and mosquitoes also live at the water column.  Insects such as water striders and mosquitoes also live at the air water interface.  Fish move through the water column, sometimes near the surface and sometimes at depth.

            Finally, the bottom or benthos is occupied by a variety of snails, burrowing worms, fish and other organisms.  Theses make up the benthic community.  Oxygen levels are lowest in the benthic environment, mainly because these is little mixing to introduce oxygen to this zone.  Anaerobic (not using oxygen) bacteria may live in low-oxygen sediments.  In the littoral zone, emergent plants, such as cattails and rushes, grow in the bottom sediment.  These plants create important functional links between layers of an aquatic ecosystem, and they may provide the greatest primary productivity to the system.

            Lakes unless they are shallow, have a warmer upper layer that is mixed by wind and warmed by the sun.  This layer is the epilimnion.  Below the epilimnion is the hypolimnion (hypo=below), a colder, deeper layer that is not mixed. 

             

Wetlands are shallow and productive

            Wetlands are shallow ecosystems in which the land surface is saturated or submerged at least part of the year.  Wetlands have vegetation that is adapted to grow under saturated conditions.  These legal definitions are important because, although wetlands make up only a small part of most countries, they are disproportionately important in conservation debates and are the focus of continual legal disputes in North America and elsewhere around the world.  These relatively small systems support rich biodiversity, and they are essential for both breeding and migrating birds.  Although wetlands occupy less than 5 percent of the land in the United States, the Fish and Wildlife Service estimates the one-third of all endangered species spend at least part of their lives in wetlands.  As water stands in wetlands, it also seeps into the ground, replenishing groundwater supplies.  Wetlands filter, and even purify, urban and farm runoff, as bacteria and plants take up nutrients and contaminants in water.  They are also in great demand for filling and development.  They are often near cities of farms, where land is valuable and once drained wetlands are easily converted to more lucrative uses.

            Wetlands are described by their vegetations.  Swamps, also called forested wetlands, are wetlands with trees.  Marshes are wetlands without trees.  Bogs are areas of water-saturated ground, and usually the ground is composed of deep layers of accumulated, undecayed vegetation known as peat.  Fens are similar to bogs except that they are mainly fed by groundwater, so that they have mineral-rich water and specially adapted plant species.  Bogs are fed mainly by precipitations.  Swamps and marshes have high biological productivity.  Bogs and fens, which are often nutrient-poor, have low biological productivity.  They may have unusual and interesting species, though, such as sundews and pitcher plants, which are adapted to capture nutrients from insects rather than from soil.

            The water in marshes and swamps usually is shallow enough to allow full penetration of sunlight and seasonal warming.  These mild conditions favor great photosynthetic activity, resulting in high productivity at all tropic levels.  In short, life is abundant and varied.  Wetlands are major breeding, nesting and migratio0n staging areas for waterfowl and shorebirds.

Streams and rivers are open systems

            Streams from wherever precipitation exceeds evaporation and surplus water drains from the land.  Within small streams, ecologists distinguish areas of riffles, where water runs rapidly over a rocky substrate, and pools which are deeper stretches of slowly moving current.  As streams collect water and merge, they form rivers, although there isn’t a universal definition of when one turns into the other.  Ecologists consider a river system to be a continuum of constantly changing environmental conditions and community inhabitants from the headwaters to the mouth of a drainage or watershed.  The biggest distinction between stream and lake ecosystems if that in a stream, materials, including plants, animals and water are continually moved downstream by flowing currents.  This downstream drift is offset by active movement of animal’s upstream, productivity in the stream itself and input of materials from adjacent wetland or uplands. 

4.5 BIODIVERSITY

  Biodiversity the variety of living things also makes the world a more beautiful and exciting place to live.  Three kinds so biodiversity are essential to preserve ecological systems and functions

4)      Genetic diversity

5)      Species diversity

6)      Ecological diversity

.

Genetic diversity

Genetic diversity is a measure of the variety of versions of the same genes within individual species. It can be estimated by the mean levels of heterozygosis in a population, the mean number of alleles per locus, or the percentage of polymorphic loci. The genetic diversity of a species is always open to change. No matter how many variants of a gene are present in a population today, only the variants that survive in the next generation can contribute to species diversity in the future. Once gene variants are lost, they cannot be recovered.

B. Species diversity

Species diversity describes the number of different kinds of organisms within individual communities or ecosystems. The number of different species in a particular area (i.e., species richness) weighted by some measure of abundance such as number of individuals or biomass. Global biodiversity is frequently expressed as the total number of species currently living on Earth that is its species richness.

C. Ecological diversity

Diversity of species with different ecosystems such as forest, wetland, grasslands, wood lands, desert etc.  The diversity of terrestrial animals varies from east to west due to differences in climate (particularly rainfall), geology, and topography and geographical Isolation.

4.6 BENEFITS OF BIODIVERSITY

Biodiversity is the totality of genes, species, and ecosystems in a region. Biodiversity can be divided into three hierarchical categories genes, species, and ecosystems that describe quite different aspects of living systems and that scientist’s measure in different ways.

• All of our food comes from other organisms
• Rare species provide important medicines
• Biodiversity  can support ecosystem stability
• Biodiversity has aesthetic and cultural benefits

• All of our food comes from other organisms

            Many wild plant species could make important contributions to human food supplies either as they are or as a source of genetic material to improve domestic crops.  There are more than 80,000 edible wild plant species is used by humans.  The Indonesian villagers used 4,000 native plants and animals species for food, medicine and other valuable products.

• Rare species provide important medicines

            Living organisms provide us with many useful drugs and medicines.  More than half of all prescription contains some natural products.  The United Nations development programme estimates the value of pharmaceutical products derived from developing world plants animals and microbes to be more than 30 billion per year.  The anticancer alkaloids are derived from the Madagascar pericells and are very effective in treating certain kinds of cancer.  Twenty years ago before these drugs were introduced childhood leukemia were invariably fatal.

• Biodiversity can support ecosystem stability

            Human life is inextricably linked to ecological services provided by other organisms.  Soil formation, waste disposal air and water purification nutrient cycling, solar energy absorption and food production all depend on biodiversity.  Total value of these ecological services is at least 33 trillion per year or more than double total world GNP.  In many environments high diversity may help biological communities withstand environmental stress better and recover quickly than those with fewer species.

• Biodiversity Has Aesthetic and Cultural Benefits

            Millions of people enjoy hunting, fishing, camping, hiking, wildlife watching and other nature-based activities.  These activities provide invigorating physical exercise and contact with nature can be psychologically and emotionally restorative.  In many cultures nature carries spiritual connotations and a particular species or landscape may be inextricably linked to a sense of identity and meaning.

4.7 THREATS TO BIODIVERSITY

            Extinction the elimination of species is a normal process of the natural world species die out and are replaced by others often their own descendants as part of evolutionary change.  In undisturbed ecosystems the rate of extinction appears to the about one species lost every decade.  Over the past century however human impacts on populations and ecosystems have accelerated that rate possibly causing thousands of species, subspecies and varieties to become extinct every year.  Ecological E.O. Wilson estimates that we are losing 10,000 species or subspecies a year that makes more than 27 per day if present trends continue we may destroy millions of kinds of plants, animals, and microbes in the next few decades. 

            In geologic history extinctions are common.  Studies of the fossil record suggest that more than 99 percent of all species that ever existed are now extinct.  Most of those species were gone long before humans came on the scene. Periodically, mass extinctions have wiped out vast numbers of species and even whole families.  The best studied of these events occurred at the end of the cretaceous period, when dinosaurs disappeared, along with at least 50 percent of existing species.  An even greater disaster occurred at the end of Permian Period, about 250 million years ago,

MASS EXTINCTIONS
Historic period	Time (Before Present)	Percent of Species Extinct
Ordovician	444 million	85
Devonian	370 million	83
Permian	250 million	95
Triassic	210 million	80
Cretaceous	65 million	76
Quaternary	present	33-66

When 90 percent of species and half of all families died out over a period of about 10,000 years a mere moment in geologic time.  Current theories suggest that these catastrophes were caused by climate changes, perhaps triggered when large asteroids struck the earth.  Many ecologists worry that global climate change caused by our release of greenhouse gases in the atmosphere could have similarly catastrophic effect.

Human activities have sharply increased extinctions

            The rare at which species are disappearing has increased dramatically over the past 150 years.  Between A.D. 1600 and 1850, human activities appear to have eliminated two or three species per decade, about double the natural extinction rate.  In the past 150 years, the extinction rate has increased to thousands per decade.  Conservation biologists call this the sixth mass extinction but note that this time it’s not asteroids or volcanoes but human impacts that are responsible E.O. Wilson summarizes human threats to biodiversity with the acronym HIPPO, which stands for Habitat destruction, Invasive species, Pollution, population (human) and over harvesting.

Habitat destruction is the aim threat for many species

            The most important extinction threat for most species especially terrestrial ones is habitat loss.  Perhaps the most obvious example of habitat destruction is clear cutting of forests and conversion of grasslands to crop fields.  Over the past 10,000 years, human have transformed billions of hectares of former forests and grasslands lot croplands, cites, roads and other uses.  Sometimes we destroy habitat as side effects of resource extraction, such as mining, dam-building and indiscriminate fishing methods.  Surface mining for example strips off the land covering along with everything growing on it.  Waste from mining operations can bury valleys and poison streams with toxic material.  Dam-building floods vital stream habitat under deep reservoirs and eliminates food sources and breeding habitat for some aquatic species.  Our current fishing methods are highly unsustainable.  One of the most destructive fishing techniques is bottom trawling, in which heavy nets are dragged across the ocean floor, scooping up every living thing and crushing the bottom structure to lifeless rubble. 

Fragmentation reduces habitat to small, isolated patches

            In addition to the total area of lost habitat, another serious problem is habitat fragmentation the reduction of habitat into small isolated patches.  Breaking up habitat reduces biodiversity because many species, such as bears and large cats, require large territories to subsist.  Other species, such as forest interior birds, reproduce successfully only in deep forest for from edges and human settlement.  Predators and invasive species often spread quickly into new regions following fragment edges.  Fragmentation also divides populations into isolated groups, making them much more vulnerable to catastrophic events, such as storms or diseases.  A very small population may not have enough breeding adults to be viable even under normal circumstances.  An important question in conservation biology is what the minimum viable population size for various species.

4.8 PRESERVE BIODIVERSITY

Biodiversity and conservation

Grasslands dominated by unsown wild-plant communities ("unimproved grasslands") can be called either natural or 'semi-natural' habitats. The majority of grasslands in temperate climates are 'semi-natural'. Although their plant communities are natural, their maintenance depends upon anthropogenic activities such as low-intensity farming, which maintains these grasslands through grazing and cutting regimes. These grasslands contain many species of wild plants - grasses, sedges, rushes and herbs - 25 or more speerican prairie grasslands or lowland wildflower meadows in the UK are now rare and their associated wild flora equally threatened. Associated with the wild-plant diversity of the "unimproved" grasslands is usually a rich invertebrate fauna; also there are many species of birds that are grassland "specialists", such as the snipe and the Great Bustard. Agriculturally improved grasslands, which dominate modern intensive agricultural landscapes, are usually poor in wild plant species due to the original diversity of plants having been destroyed by cultivation, the original wild-plant communities having been replaced by sown monocultures of cultivated varieties of grasses and clovers, such as Perennial ryegrass and White Clover. In many parts of the world "unimproved" grasslands are one of the least threatened habitats, and a target for acquisition by wildlife conservation groups or for special grants to landowners who are encouraged to manage them appropriately.

There are two methods of biodiversity conservation, in situ and ex situ. The former envisages conservation within the natural ecosystem such as protected areas (wildlife sanctuaries, national parks, biosphere reserves, heritage sites, etc.), and the latter is a method of conservation outside natural habitats (botanical and zoological gardens, gene banks, seed banks etc). In case of domesticated or cultivated species, conservation means conservation in the surroundings where they have developed their distinctive properties.

Global Initiate

In addition to the aforesaid conservation programmes, laws related to intellectual property rightly from part of the global initiates in biodiversity conservation. A product derived by the activity of the productive human mind or intellect is referred to as intellectual property. Cultural and artistically knowledge, industrial designs, logos that come in the ambit of trade marks (pictorial or verbal), music related products, sound recording, biotechnology products, industrial secrets, etc comes with in the framework of intellectual properties.

Intellectual Property Acts

v  Patent Patent Act 1970

v  Copyright Copyright Act 2000

v  Trade mark Trade mark Act 1999

v  Design Design Act 2000

v  Circuit layout Semiconductor Intended layout Design Act 2000

v  Geographical indicators GI of Goods (Registration Protection) Act 1999

v  Biodiversity Biodiversity Act 2002

v  New Plant varieties New Plant varieties and Farmers Rights

v  Protection Act 2001

 Activities in India

Several activities related to biodiversity conservation are going on in India. Many such activities, including formation of biosphere reserves, are centered in biodiversity-rich forests ecosystems. In addition to this, many ecosystems such as wetlands, mangroves and sacred groves have also been brought under conservation schemes. Project Elephant, Project Tiger, project rhino, project hangul etc.are some of the national efforts in India towards conservation of selected individual species. National Botanic Gardens have been established at Lucknow and Kolkata for the conservation of plants. Further, there are Orchidaria at Yercard and Meghalaya for the conservation of orchids. The Government of India has also enacted several laws aimed at conserving our rich In addition to this there are special projects biodiversity.

Acts and Rules

Government of India constituted a National Biodiversity Authority (NBA) at Chennai in 2003 with the aim of conservation of biodiversity. The Biological Diversity Act, 2002 is formed for the conservation and sustainable utilization of biodiversity and for equitable sharing benefits arising out of the uses of biodiversity and its components.

Programmes

As per the provisions if the Biological Diversity Act, 2002 and the Biological Diversity Rules, 2004 several programmes have been initiated in the States. The Biological Diversity Rules 2004 provide legal support for biodiversity conservation, protection of IPR and for the formation of State Biodiversity Boards. State Biodiversity Boards have been constituted in majority of States. The following are the responsibilities of State Biodiversity Boards:

i. Advice the State Government, subjected to any guidelines issued by the Central

Government, on matters related to conservation of Biodiversity, sustainable utilization of its components, and equitable sharing of benefits arising out of the utilization of biodiversity.

ii. Regulate the commercial utilization of biodiversity by Indians by granting

approvals or otherwise, and iii. Perform such other function a may be necessary to carry out the provisions of this Actor as may be prescribed by the State Government. Establishment of Biodiversity Management Committee (BMCs) at all three local bodies –Grama Panchayath, Block Panchayath and District Panchayath- is one of the prime responsibilities of the State Biodiversity Board.

Responsibilities of Local Bodies

BMCs should be constituted at Grama Panchayath, Block Panchayath and District Panchayath levels. The purpose of this is promote conservation, sustainable use, documentation of biological diversity including preservation of habitats, conservation of land races (primitive cultivars which were grown by ancient farmers and their successors), folk varieties and cultivars, domesticated stocks and breeds of animals and microorganisms and documentation of knowledge relating to biodiversity. Preparation of biodiversity register also forms a major activity of BMCs. The authority of these registers should be kept and modified periodically. Information/knowledge gathered on biodiversity, traditional knowledge, sharing of benefits arising out of the uses of biodiversity, etc should be registered in this register. The BMCs may levy charges by way of collection of fees from any person for assessing or collecting any biological resource for commercial purposes. Taking cognizance of the provisions of the Biological Diversity Act, 2002 and the Biological Diversity Act, 2002 and the Biological Diversity Rules, 2004, National Biodiversity Authority and State Biodiversity Boards were constituted in India.

4.9 ENDANGERED SPECIES MANAGEMENT AND BIODIVERSITY PROTECTION

            The populations have gradually become aware of the harm we have done and continue to do to wildlife and biological resources.  Slowly we are adopting national legislation and international treaties to protect these irreplaceable assets.  Parks, wildlife refuges, nature preserves, zoos and restoration programs have been established to protect nature and rebuild depleted populations.  There has been encouraging progress in this are but much remains to be done.  While most people favor pollution control or protection of favored species, such as whales or gorillas, surveys show the few understand what biological diversity and its important.

Hunting and fishing laws protect reproductive populations

            In 1874 bill was introduced in the United States Congress to protect the American bison, whose numbers were already falling to dangerous levels.  This initiative failed, however because most legislators believed that all wildlife and nature in general was so abundant and prolific that it could never be depleted by human activity.

            By the 1890 s most states had enacted states had enacted some hunting and fishing restrictions.  The general idea behind these laws was to conserve the resource for future human use rather than to preserve wildlife for its own sake.  The wildlife regulations and refuges established since that time have been remarkably successful for many species.  A hundred years ago there were estimated halves a million white-tailed deer in the United States now there are some 14million more in some places than the environment can support.  Wild turkeys and wood ducks were nearly and wood ducks were nearly gone 50 years ago.  By restoring habitat, planting food crops, transplanting breeding stock, building shelters or houses, protecting theses birds during breeding seasons and using other conservation measures, we have restored populations of these beautiful and interesting birds to several million each.

Conservation Issues

Major ecological characteristics of the High Plains and Rolling Plains have been forever changed by use of the plow for agriculture, barbed wire fencing to control grazing animals, and by prevention of natural fires during the past century. Nonetheless, some fragile and unique habitats such as sand shinnery oak-sand sage dunes survive in areas southwest of Lubbock and northeast of Amarillo; and, sub-irrigated wet meadows persist along portions of the Canadian River and other riparian systems east of Pampa, Clarendon, and Childress. These areas are almost exclusively in private stewardship and are rich in biodiversity. However, due to large-scale habitat loss, alteration, or degradation, some species occurring in the High Plains and Rolling Plains are categorized as threatened or endangered. Destruction/degradation of habitat is clearly the number one cause for decline and or potential extinction of species, not only within these two regions of Texas, but throughout the state.

Approximately 16 million acres of native short and mixed-grass prairie currently exist in the Texas panhandle. These native prairies provide important habitat to a variety of resident and migratory wildlife, many of which are species of concern. Some of the more visible species include black-tailed prairie dogs and pronghorns, while others like the swift fox, mountain plover and lesser prairie-chicken are more secretive and are more difficult to observe.

Short and mixed-grass prairies of the High Plains and Rolling Plains were historically shaped by the forces of climate, grazing, and fire (Gillihan et al. 2001). Because of these forces, grassland wildlife species had continual access to a variety of habitats in different stages of plant growth. In essence, herds of grazing animals could move among the variety of habitats available until a suitable one was found (e.g., more palatable vegetation). As a result, the amount of natural vegetative structure and diversity for all species within these two vast prairie regions was great. Today, modern grazing practitioners strive to insure more even use of livestock forage, including native prairies, through controlled distribution of grazing animals, which results in a landscape that varies little (or less than historically) from one area to another. The diversity (both over time and space) of habitats has been reduced; in short, quantity and quality of habitat for many grassland species has declined.

During the past 100 years, more than half of the native prairies in Texas have been lost to urban development or converted to cropland. Loss of habitat has caused concern about some of the prairie-dependent species like the lesser prairie-chicken, swift fox, mountain plover, black-tailed prairie dog, and pronghorns. Most rare species inhabit privately owned and managed lands in Texas. Incentive programs to assist private landowners in protecting and managing habitats for all wildlife, including rare species, can have a direct and positive impact on their conservation. Therefore, Texas Parks and Wildlife offers the Landowner Incentive Program to provide financial incentives that encourage landowners to help conserve habitats for rare and declining species. The program is flexible and is available to all private landowners wishing to voluntarily improve land health with a focus on rare declining species

The endangered species act protects habitat and species

            Establishment of the U.S. Endangered Species Act (ESA) of 1973 and the committee on the status of Endangered Wildlife in Canada (COSEWIC) IN 1976 represented powerful new approaches to wildlife protection.  Where earlier regulations had been focused almost exclusively on “game” animals, theses programs seek to identify all endangered species and populations and to save as much biodiversity as possible, regardless of its usefulness to humans.  Endangered species are those considered in imminent danger of extinction, while threatened species are those that are likely to become endangered at least locally within the foreseeable future.   Vulnerable species are naturally rare or have been locally depleted by human activities to a level that puts them at risk. 

Recovery plans

Once a species is officially listed as endangered the fish and wildlife service is required to prepare a recovery plan detailing how populations will be rebuilt to sustainable levels.  It usually takes years to reach agreement on specific recovery plans.

v  Keystone species are those with major effects on ecological functions and whose elimination would affect many other members of the biological community, example are prairie dogs (Cynomys ludovicianus) Bison (Bison bison)

v  Indicator species are those tied to specific biotic communities or successional stages or environmental conditions.  They can be reliably found under certain conditions but not others an example is brook trout (Salvelinus fontinalis)

v  Umberlla species requires large blocks of relatively undisturbed habitat to maintain viable populations.  Saving this habitat also benefits other species. Example of umbrella species are the northern spotted owl (Strix occidentalis caurina) and tiger (Panthera tigiris)

v  Flagship species are especially interesting or attractive organisms to which people react emotionally.  These species can motivate the public to preserve biodiversity and contribute to conservation and example is the giant panda (Ailuropoda melanoleuca).

Reauthorizing the ESA has been contentious

            The ESA officially expired in 1992. Since then, congress has debated many alternative proposals ranging from outright elimination to substantial strengthening of the act.  Perhaps no other environmental issue divides Americans more strongly than the ESA.  Environmentalists on the other hand, see the ESA as essential to protecting nature and maintaining the viability of the planet.  They regard it as the single most effective law in their arsenal and want it enhanced and improved.

International wildlife treaties protect global biodiversity

            The 1975 convention on International Trade in endangered species (CITES) was a significant step toward worldwide protection of endangered flora and fauna.  It regulated trade in living specimens and products derived from listed species, but it has not been foolproof. Species are smuggled out of countries where they are threatened or endangered and documents are falsified to make it appear they have come from areas where the species are still common.  Investigations and enforcement are especially difficult in developing countries were wildlife is disappearing most rapidly.  Still eliminating markets for endangered wildlife is an effective way of stopping poaching. 

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UNIT V

5.1 ENVIRONMENTAL CONSERVATION

Environmental conservation is the saving of our environment and its natural byproducts. An example of environmental conservation is the dying need to save our forest trees, as trees are the source of oxygen that we depend on to live.  Environmental conservation is important because if we use up our natural resources we will eventually run out of them. Take forests and plants for example. Without forests and plants there is no oxygen for us to breathe Environmental protection is a practice of protecting the environment, on individual, organizational or governmental level, for the benefit of the natural environment and (or) humans. Due to the pressures of population and our technology the biophysical environment is being degraded, sometimes permanently. This has been recognized and governments began placing restraints on activities that caused environmental degradation. Since the 1960s activism by the environmental movement has created awareness of the various environmental issues. There is not a full agreement on the extent of the environmental impact of human activity and protection measures are occasionally criticized.

Academic institutions now offer courses such as environmental studies, environmental management and environmental engineering that study the history and methods of environmental protection. Protection of the environment is needed from various human activities. Waste, pollution, loss of biodiversity, introduction of invasive species, release of genetically modified organisms and toxics are some of the issues relating to environmental protection.

Environmental protection definition includes all available practices used to protect our environment, whether on individual, organizational or global (international) level. This basically means that each and every one of us can do something to protect our environment but of course, global actions are the ones that would.

Help our environment the most.

The general opinion is that our environment is in the constant state of degradation due to so many different environmental problems (climate change, all forms of pollution, deforestation, biodiversity loss, etc). The scientists have been issuing warnings about the negative state of our environment for quite some time but unfortunately world leaders do not listen to science and global action to protect our environment from further degradation still looks like mission impossible. This was best demonstrated in talks about the new climate change deal where world leaders once again failed to find the mutual language being divided by different individual interest.  Human population is constantly growing, and world still fails to find the right balance between the increase in human population and environmental needs. More people on this planet means more environmental problems quite simply because our society doesn't have the ecological conscience. In the world where everything is about the money it is impossible to develop global ecological conscience, and install it into our society.

In simple words we care too little for our environment and our planet in general. We have come to a point where we need to protect environment against ourselves, and that is the worst possible irony. Yes, there are many different organizations that try to protect our environment such as Environmental Protection Agency in United States but without the global ecological conscience.

Very little can be achieved. Some environmentalists even say that the environmental protection has become a lost cause because environmental problems keep on growing at rapid pace, giving us a zero chance to do something about it.

Calling environmental protection a lost cause is going too far because as long there is at least one healthy environment left in the world, environmental protection has its purpose, and is not completely useless as some may think it is. Without the environmental protection our environment would look much worse than it looks today, and we certainly must look for more.

Ways to protect our environment.

Many countries have different organizations and other bodies devoted to environmental protection. There are even some international environmental protection organizations, for instance the United Nations Environment Programme. This means that something is still being done for our environment, though this something is far.

From being enough.

The most important thing in today's ecology is to solve things on global level, and environmental protection is no exception. World leaders must act as one when it comes to environment because this is the only possible.

Road to successful environmental protection.  Only united world can save our environment and our planet for our future generations. Our planet, our environment, our responsibility.

5.2 WORLD FORESTS AND GRASSLANDS

            Forests and grasslands together occupy almost 60 percent of global land cover.  These ecosystems provide many of our essential resources, such as lumber paper, pulp, and grazing lands for livestock.  They also provide essential ecological services, including regulating climate, controlling water runoff providing wildlife habitat purifying air and water and supporting rainfall.  Forests and grasslands also have scenic, cultural and historic values that deserve protection.  Forests and grassland are also among the most heavily disturbed ecosystems.

            In many cases, these competing land uses and needs are incompatible.  Most political debates over conservation have concerned protection or use of forests, prairies and rangelands. 

BOREAL AND TROPICAL FORESTS ARE MOST ABUNDANT

            Forests are widely distributed but most remaining forests are in the humid tropics and the cold boreal (“northern”) or taiga regions.  Assessing forest distribution is tricky, because forests vary in density and height and many are inaccessible.  The UN  Food and Agriculture Organization (FAO) define “forest” as any area where trees cover more than 10 percent of the land.  This definition includes woodlands raging from open savannas whose trees cover less than 20 percent of the ground to closed canopy forest in which tree crowns cover most of the ground.  The largest tropical forest is in the Amazon River basin. 

            Forests are a huge carbon sink, storing some 422 billion metric tons of carbon in standing biomass.  Clearing and burning of forests releases much of this carbon into the atmosphere and may contribute substantially to global climate change.  Moisture releases from forests also contributes to rainfall.  For example recent climate studies suggest that deforestation of the Amazon could reduce precipitation in the American Midwest.  While forests still cover about half the area they once did worldwide, only one-quarter of those forests retain old-growth forest are in Russia, Canada, Brazil, Indonesia and Papua New Guinea Together these five countries account for more than three quarters of all relatively undisturbed forests in the world.  In general remoteness rather than laws protect those forests.  Although official data describe only about one-fifth of Russia old-growth forest as threatened, rapid deforestation both legal and illegal especially in the Russian Far East probably put a much greater area at risk.

FOREST PROTECTION

            Many countries now recognize that forests are valuable resources. Intensive scientific investigations are underway to identify the best remaining natural areas. About 12% of all world forests are in some form of protected status, but the effectiveness of that Protection varies greatly. Costa Rica has one of the best plans for forest guardianship in the world. Attempts are being made there not only to rehabilitate the land (make an area useful to humans) but also to restore the ecosystems to naturally occurring associations. One of the best-known of these projects is Dan Janzen’s work in Guanacaste National Park. Like many dry, tropical forests, the northwestern part of Costa Rica had been almost completely converted to ranchland. By controlling fires, however, Janzen also permits grazing in the park. The original forest evolved, he reasons, together with ancient grazing animals that are now extinct. Horses and cows can play a valuable role as  seed dispersers.

5.3 GRASSLAND

Grassland is a grassy, windy, partly-dry biome, a sea of grass. Almost one-fourth of the Earth's land area is grassland. In many areas, grasslands separate forests from deserts. Deep-rooted grasses dominate the flora in grassland there are very few trees and shrubs in grassland, less than one tree per acre. There are many different words for grassland environments around the world, including savannas, pampas, Campos, plains, steppes, prairies and veldts.

There are two types of grasslands, including:

Tropical grassland - hot all year with wet seasons that bring torrential rains. Located between the Tropic of Cancer and the Tropic of Capricorn, sometimes called savannas.

Temperate grasslands - hot summers and cold winters. The evaporation rate is high, so little rain makes it into the rich soil. Located north of the Tropic of Cancer and south of the Tropic of Capricorn

Grassland types (biomes)

Tropical and subtropical grasslands

These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America.

 Temperate grasslands

Mid-latitude grasslands, including the Prairie and Pacific Grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.

5.4 ECOSYSTEM PRESERVATION

While most forests and grasslands serve useful or utilitarian purposes most societies also set aside some natural areas for aesthetic or recreational purposes.  Natural preserves have existed for thousands of years.  Ancient Greeks protected sacred groves for religious purposes.  Royal hunting grounds have preserved forests in Europe for countries.  Although these areas were usually reserved for elite classes in society they have maintained biodiversity and natural landscapes in regions where most lands are heavily used.

The first public parks open to ordinary citizens may have been the tree-sheltered agoras in planned Greek cities.  But the idea of providing natural space for recreation and to preserve natural environments has really developed in the past century or so.  While the first parks were intended mainly   for the recreation of growing urban populations parks have taken on may additional purposes.  National parks serve many purposes Yellowstone National Park was the first national park in the world established in 1872 by president Ulysses S.Grant.

Scientific evidence shows that ecosystems are under unprecedented pressure, threatening prospects for sustainable development. While the challenges are daunting, they also provide opportunities for local communities, business and government to innovate for the benefit of communities, economies and the global environment. However, in order to secure the environmental conditions for prosperity, stability and equity, timely responses that are proportionate to the scale of the environmental challenges will be required. In creating such responses, governments, the international community, the private sector, civil society and the general public all have an important role to play. As the environmental programme of the United Nations, UNEP is working to articulate, facilitate and support appropriate responses.

5.5 WORLD PARKS AND PRESERVES

            The idea of setting aside nature preserves has spread rapidly over the past 50 years.  Regions with the most dramatic increases have been Asia, North America and Latin America, Brazil has recently pledged to protect 12% of its rainforest, paper parks.  In many cases it is easier to declare a new park than protect and manage it even existion parks are not safe form exploitation.

National Parks and Preserves, unique public lands or bodies of water within a country, ser aside by the government to protect ecosystems, plants and animal species, scenic landscape, geologic formations or historical or archaegeological sites.

            National parks are managed primarily for public recreation, providing exceptional locations where visitors can view wildlife and enjoy the outdoors.  Generally, these protected public lands are off-limits to hunting, livestock grazing, logging, mining, and other activities that exploit natural resources.  Some parks commemorate significant historical events.   for example Gettysburg National Military Park 1895 in Pennsylvania conserves the 13sq km (5 sq mi) site of the pivotal battle in the American civil war (1861-1865)

            The world’s first national park, Yellowstone national park, was created in the western United States in 1872 to reserve for public recreation 8983 sq km (3469 sq mi) of geothermally unique forest land.  Since then countries around the world have established more than 4000 national parks and preserves.  Many national parks and preserves protect remote, unspoiled natural environments, while some protect island of wilderness within heavily populated regions. Argentina’s national parks movement started in 1903 now the land now within 3277sq km. In Britain both the national trust

5.6 WILDERNESS AREAS

            Wilderness areas a belief that wilderness is a sources of wealth and the origin of strength, self-reliance, wisdom and character is deeply embedded in our culture.  1964 wilderness act defined wilderness “An area of undeveloped land affected primarily by the forces of nature, where man is a visitor who does not remain”. 40 million ha in US in 264 wilderness preserves

            With the exception of the five high-biodiversity wilderness areas, this study reveals that the targets of biodiversity conservation and of wilderness conservation are generally different.  Although they surely hold the bulk of the planets biomass and also the last remaining intact mega faunal assemblages the wilderness areas hold many fewer species than expected.

5.7 WILDLIFE REFUGES

Ø  1901 president Teddy Roosevelt established 51 national wildlife refuges

Ø  Now 540 refuges encompassing 40 million ha representing every major nbiome in North America

Ø  Refuge management

Ø  Originally intended to be sanctuaries in which wildlife would be protected from hunting or other disturbances

Ø  1948 Hunting allowed in refuges

Ø  Over the years, a number of other uses have been allowed to operate within wildlife refuge boundaries

Ø  oil and gas drilling

Ø  cattle grazing

Ø  motor boating camping

Ø  refuges also face threats from external sources expanding human populations

                                                  

Ø  water pollution.

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