ESE - UNIT I ENVIRONMENT, ECOSYSTEMS & BIODIVERSITY DEFINITIONS: Environment: Any thing that surrounds us constitutes environment. It includes biotic

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1 ESE - UNIT I ENVIRONMENT, ECOSYSTEMS & BIODIVERSITY DEFINITIONS: Environment: Any thing that surrounds us constitutes environment. It includes biotic and abiotic components in addition to the human being. Environmental Science: The study of basic components of our surroundings and their interaction is called environmental science. Environmental Studies: The process of educating people on environment and its problems is called environmental studies. SCOPE OF ENVIRONMENTAL STUDIES The scope and objective of the environmental studies is to cultivate people to be aware and concerned about total environment and its associated problems and commitment to work individually and collectively towards solution of current problems & the prevention of new ones. Scopes: 1. To get an awareness and sensitivity to the total environment and its allied problems. 2. Acquiring basic understanding of total environment problems and the responsible presence of humanity in it. 3. Inculcating a set of social values and strong feeling of environment concern. 4. To motivate active participation in environmental protection and improvement. 5. Developing skills to identity and solve environmental related problems. 6. Ability to evaluate environmental programmes in terms of ecology, economy, etc 7. To promote the value and necessity of local, national and international co-operation in the prevention of environmental problems. 8. To help the public to know the real causes of environmental problems and contribute towards solving them. 9. To give clear picture about the current potential of resources and environmental situations. 10. Environmental studies give an idea and understanding about the inter-dependence of nature and people. 11. To focus on plans for growth and development through environmental aspects. 12. An environmental study is a continuous process, aimed at creating an environmentally responsible society. IMPORTANCE OF ENVIRONMENTAL STUDIES All the industry is polluting one way or the other and none of them is safe. There is no zero pollution industry. The air we breathe, the water we drink, the food we consume and the land we live on are all contaminated by industrial activities. Because of the lack of self discipline and not worrying about our future generation, we are polluting our valuable resources. By means of good environment like pure water, clean air, sanitation and hygienic atmosphere, the society can live 1

2 for long periods. To solve the environmental related issues, the knowledge of environmental studies is very important. Importance: 1. Through environmental studies one can understand how attitudes and values can affect the environment at present and as well as in the future. 2. An environmental study has a direct relation to the quality of life we live. 3. Environmental studies relates to our surroundings which we observe daily but never think seriously. 4. By teaching environmental studies, the people should understand the concept of need of development without destruction of environment (sustainable development). 5. Environmental studies develop a concern and respect for the environment. 6. Environmental studies inform people as to how they can play an effective role in protecting the environment by demanding changes in laws and enforcement systems. NEED FOR PUBLIC AWARENESS The man made activities like urbanization, industrialization, agricultural and economic development creates various environmental problems and threatening whole biosphere. So it is necessary to create awareness about the environment to the public. We are conducting several conferences, enforcing laws and adopting several policies to protect our environment. But it is very difficult to achieve the goal without creating awareness to the public about environment conservation. Hence public awareness is needed to protect our only living planet earth. CONCEPT OF AN ECOSYSTEM The term ecosystem was first defined by A.G. Tansley in Eco means environment and system means assemblage of objects. Ecology: The study of ecosystem is called ecology. Ecosystem: The system in which group of biotic and abiotic components are inter-related one another is called ecosystem. Ex. Forest ecosystem, marine ecosystem, etc. STRUCTURE Ecosystem includes, a) Biotic components: It includes all the living organisms such as human beings, animals, plants and microbes in our earth. b) Abiotic components: It includes all the non-living matter such as soil, minerals, water, air, light, nutrients, etc in our earth. 2

3 c) Movement of energy & mineral nutrients: The green plants prepare its own food through photosynthesis. Small herbivores, consume the nutrient rich vegetable matter and they serve as food to carnivores (meat eating) which in turn eaten by top carnivores. This sequence of eating and being eaten produces transfer of energy and mineral nutrients. FUNCTION The function of the ecosystem is dynamic. The various components of the ecosystem constitute an inter-relationship between each other. They are connected by energy, nutrients and minerals. The metabolism includes assimilation, respiration, growth and production, etc. Energy flow involves transfer of energy from producer to various consumers. The bio-geochemical cycle circulates materials and water in between biotic and abiotic components. The biological regulations maintain the relation between the biotic and abiotic components. a) Producers (Autotrophs): Those organisms producing their own food through photosynthesis are called producers. Ex. Plants, algae, etc b) Consumers (Heterotrophs): Those organisms feeding on other organisms are called consumers. They are classified into primary consumer (herbivores) and secondary consumers (carnivores). Herbivores: Plant eating animals are called herbivores. Ex. Deer, Cow, etc. Carnivores: Meat eating animals are called carnivores. Ex. Jackel, Wolf, Lion, etc. Omnivores: Those organisms which derive their energy from both producers and consumers are called omnivores. Ex. Human being, crow, etc. c) Decomposers (Reducers): Those organisms break down complex compounds of dead organisms are called decomposers. Ex. Bacteria and fungi. ENERGY FLOW The flow of energy from producer level to top consumer level is called energy flow. The energy flow is in unidirectional; it flows from the producer to consumer and never in the reverse direction. The main source of energy in the ecosystem is sunlight. The green plants prepare their 3

4 food through photosynthesis. The herbivores consume the nutrient rich vegetable matter and they may serve as food to carnivores which in turn are eater by large carnivores. Hence, the amount of energy transfers from producer level to the decomposer level. Thus the exchange of minerals, matter and energy among the various biotic components is the essential function of an ecosystem. ECOLOGICAL SUCCESSION The sequential changes of community over a period of time in the same area are called ecological succession. There are two types, Primary & Secondary succession. The community development starts on a sterile area is called primary succession and the succession starts on the areas previously occupied by well developed communities is called secondary succession. FOOD CHAIN The green plants prepare their own food through photosynthesis. Small herbivores, consume the nutrient rich vegetable matter and they serve as food to carnivores (meat eating) which in turn eaten by top carnivores. The sequence of eaters and being eaten is called food chain. FOOD WEB The food relationship is being depicted by linking all the possible prey and predator of different food level is called food web. Also it can be defined as In an ecosystem, various food chains are inter connected with each other to form a net work is called food web. 4

5 ECOLOGICAL PYRAMID The graphical representation of the number, biomass and energy of the successive trophic levels of an ecosystem is called food pyramid or ecological pyramid. In the ecological pyramid, the producer is at the base and the successive levels place at the top one by one. There are two types of pyramids. A) Upright pyramid B) Inverted pyramid. The ecosystem in which the number and biomass of producers are more than that of consumers are less is called upright eco-pyramid. And the ecosystem in which the number and biomass of producers are lesser than that of consumers are called inverted eco-pyramid. FOREST ECOSYSTEM: Forest is a natural ecosystem consisting of dense growth of trees and wildlife. Biotic components: Trees, shrubs and animals. Abiotic components: Soil, sunlight, temperature, water, etc Producers: Trees and shrubs; Herbivores: Birds, Lizard and grass hopper, etc Primary consumers: Elephant, deers and giraffe, etc Secondary consumers: Lion, tiger, etc; Decomposers: Fungi and bacteria Food chain: Ecological pyramid: In the forest ecosystem the producer are the large trees which are more in number and form the base of the pyramid. The primary consumers (herbivores) are deer, birds, elephants, etc are less in 5

6 number than producers. Thereafter, the number gradually decreases thus making the upright pyramid. GRASS LAND ECOSYSTEM: Grass land ecosystem consisting major part of grass and limited shrubs and trees. Biotic components: Grasses, shrubs, etc Abiotic components: Soil, sunlight, temperature, water, and other elements like C, O, N, P and S, etc Producers: Trees and shrubs; Herbivores: Birds, Lizard and grass hopper, etc Primary consumers: Cows, buffaloes, deers, goat, insect, termites, millipedes, etc Secondary consumers: foxes, snakes, frogs, Jackal,etc; Decomposers: Fungi and bacteria Food chain: Ecological pyramid: In grass land ecosystem grass is eaten by grasshopper, mouse and rabbit. Grasshopper is eaten by lizard which is eaten by hawk. Rabbit is eaten by snake and the snake is eaten by hawk. In addition, hawk also directly eats grasshopper and rabbit. All the above food chains are interlinked with each other at different points and form food webs. The number pyramid of this ecosystem is upright in shape. DESERT ECOSYSTEM The land which receives annual rainfall below 25 cm, contain a large waste land and poor water source is called desert. Biotic components: Shrubs, bushes, few trees, camel, samphar deer, red foxes, jungle cats, wolf, ant eaters, reptiles, insect, etc Abiotic components: solar energy, air, nutrients from soil, etc Producers: Xerophytes, shrubs, bushes, few trees, etc Consumers: camel, samphar deer, red foxes, etc; Decomposers: Fungi and bacteria 6

7 Food chain: Ecological pyramid: In desert ecosystem is shrub, bushes are eaten by samphar deer, came. The camel, samphar deer are eaten by reptiles which are eaten by hawk. All the above food chains are interlinked with each other at different points and form food webs. The number pyramid of this ecosystem is upright in shape. AQUATIC ECOSYSTEM The aquatic ecosystem includes ponds, lakes, rivers, oceans and estuaries, etc which are self-sufficient and self-regulating natural ecosystem. Biotic components: Green plants, hydrophytes, phytoplankton, algae, molluscan, small fishes, zooplankton, tadpole, etc Abiotic components: Water, dissolved minerals, oxygen, carbon dioxide and solar energy Producers: Green plants, hydrophytes, phytoplankton, algae, hydrophyte, etc Primary consumers: Zooplankton, tadpole, benthos, mollusk, fishes, etc Secondary consumers: Frog, fishes, snakes, crab, etc Decomposers: Bacteria and fungi Food chain: Ecological pyramid: In aquatic ecosystem the producers which are mainly the phytoplanktons such as algae, bacteria etc are maximum in number, the herbivores, zooplanktons, small fishes are lesser in number than the producers. The secondary consumers, such as frog, crab, still less in number. Finally the top consumers are very less in numbers. Hence, the number pyramid becomes upright. 7

8 BIO-DIVERSITY Definition: It is the total number of plant, animal and microbe species living in the biosphere. It is the abbreviation of biological diversity. The biosphere contains more than 10 million species (plants and animals) of organisms. They differ widely from one another. This variation in living organisms is called biodiversity. That is the word biodiversity means wide variety of life on the earth. Genetic diversity: Within a species there are number of varieties which are slightly different from one another due to their genetic code. This is called genetic diversity. Species diversity: The biotic components include large number of species of plants, animals and microbes react with themselves and with abiotic components. The diversity between species is called species diversity. Ecosystem diversity: The diversity at the ecological or habitat level is called ecosystem diversity. BIOGEOGRAPHICAL CLASSIFICATION OF INDIA There are three ecological sub-regions. 8

9 1. Himalayan mountain system: There are altitudinal as well as East West variations in this region. Altitude affects wildlife distribution. East west variations occur due to decrease in the monsoon rainfall towards the west. The western side receives low rainfall and eastern sides falls heavy rain. The species of animals and plants in himalaya are entirely differ. A) Himalayan foot hills: It covers eastern frontiers of Kashmir to assam with evergreen forest and big mammals. B) Western Himalayas: It includes higher altitudes area with coniferous pine forest, wild ass, wild goats, etc C) Easter Himalayas: It includes sikkim and extension with coniferous forest, red panda, etc 2. Peninsular India sub-region: This covers the area around Deccan Plateau A) Peninsular India extension upto ganga river. It is full of trophical moist deciduous forest. Also elephant, wild boar, deers, etc live there. B) Thar desert: It has unique plants and animals. It includes thony trees and rodent mammal. 3. Trophical rain forest: This is the region of heavy rainfall covering North-Eastern India and Western ghats. It is full of grass with ever green forest. It includes Nilgiris, anamalai, and palani hills. A) Andaman & Nicobar islands: It is full of trophical forest and mangroves on coastal area. The spcies of mammals, reptiles and marine animals occur in this area. B) Mangrove swamps of sunderban: It covers 70 % of mangrove forest. The fish, spotted deer, sunderbans tiger, etc found in this area. VALUE OF BIODIVERSITY 1. Consumptive use: The resource which is used directly without passing through a market. Example: Fuel wood, Recreation on forest, water falls, etc 2. Productive use: The biodiversity product is used indirectly through market. Example: Timber, seeds, fruits, medicines, fibres, gums, resins, honey, etc 3. Social value: It refers value of biodiversity in the society. Example: Agriculture in India 4. Ethical value: The biodiversity is considered to have a great value on religious and cultural basis and worshiped. In India, rivers, trees, mountains, etc are worshiped. 5. Aesthetic value: The beautiful nature of plant and animal insist us to protect biodiversity. Example: Rose flower, Peacock, elephant, etc 6. Optional value: It is the potential value of the resource for future use. 9

10 Red Data Book: The book which categorizes species at the threshold of risk according to the severity of the threat is called red data book (OR) The book which contains the details of the endangered and endemic species, causes, conservation, etc is called red data book. HOT SPOTS OF BIODIVERSITY Endemic species: The species which are confined to a particular locality only are called endemic species. Hot spots: The area / region which possess endemic species is called hot spot. Conditions for Hot spots: a) The site should already be threatened b) It should include a diverse range of habitats c) It should have a significant number of specialist species d) It should contain gene pools. In India, Eastern Himalaya is considered as hot spot. In world 12 hot spots contain 34,400 endemic plant species in all tropical forest. THREATS TO BIODIVERSITY It is mainly due to A) Habitat loss B) Poaching of wildlife C) Man-Wildlife Conflicts Habitat loss: The habitat loss is mainly due to deforestation activities. Cutting trees for timber and removal medicinal plants due to its economic value are the main reasons for deforestation. Many plants becomes extinct due to the production of hybrid seeds For the production of drugs in pharmaceutical several wild plants become threat Illegal trade on wildlife also reduces the biodiversity and leads to habitat loss. Growing demand for land, energy and water supply creates loss of biodiversity Increasing human population is the main factor Forest encroachment, construction of dams, discharge of industrial effluents, etc Poaching of wildlife: The world wildlife is invaluable and irreplaceable resource. But due to poaching, illegal trade, smuggling activities they become under threat. In 1950, tigers existed in the world, now it is less than 7500 remain in the forest because of habitat loss and poaching for their furs and bones. Bushmeat is an important source of protein for many local people in Africa. So that population of bushmeat is decreasing. The population of elephant is decreasing due to hunting, culling and trade in ivory. The high-tech fishing through giant factory trawlers and practice of dynamite fishing threatens ocean marine life. 10

11 The species sea horse, star turtles become threatened due to their foreign market value Man-wildlife conflicts: It is due to deforestation, encroachment of forests and urbanization. More space to be provided for national parks, wildlife sanctuaries and bio-reserves to save wildlife. Stabilize the growing human population to conserve the biodiversity. The eco-friendly industries alone to be permitted. The development and constructional activities around forest area should be stopped. ENDANGERED SPECIES There are certain species of plants and animals are in the verge of disappearing from the earth due to man made activities are called endangered species (threatened species). Example: Tiger, Black Rhinoceros, Giant Panda, Himalayan black bear, Egyptean land tortoise, etc. Endangered species of India: India presently contains about species of plants and species of animals. Example: Cheetah, lion-tailed monkey, squirrels, deer, mahseer and tront fishes, etc CONSERVATION OF BIODIVERSITY Importance of biodiversity in ecology: 1. Enriching soil 2. Maintaining water and climate cycle 3. Conservation of waste materials into nutrients 4. Providing food, medicine and other essential materials 5. Rich biodiversity is an indicator of the health of a particular habitat and its potential to sustain life. 11

12 The problems disturbing the nature of biodiversity are as follows: 1. Dam construction 2. Release of industrial effluents 3. Application of chemicals in the agriculture field 4. Encroachment upon forest 5. Damaging marine system due to oil spills and discharge of effluents 6. Global warming 7. Ozone depletion 8. Toxic pollution Thus no species can be called back by any law or policy. Each one is unique, precious and irreplaceable. To solve above problems it is essential to conserve our biodiversity. In-Situ Conservation of Biodiversity In-Situ conservation involves conservation of species in its natural habitat places where the species normally occurs. In this method biodiversity conserved where it currently exists. Steps: a) Establishment of small or large protected area exclusively for wildlife b) Restrict the human activities such as hunting, timber extraction, fire wood collection, etc Methods: 1) Nature or Biosphere Reserve: The nature or biosphere reserve covers large area more than 5000 sq. km where no exploitative human activities or tourism is permitted. The aim of biosphere Reserve: a) To give long term survival of evolving ecosystem b) To conserve maximum number of species and communities c) To protect endangered species d) Biological reserves are very useful for educational and research purpose e) To serve as sites of recreation and tourism 2) National parks and sanctuaries: They are small reserves covering an area about 100 sq. km to 500 sq. km and protecting the species and their habitats. The boundaries of national parks are well defined and that of sanctuary are not well defined. But tourism is permitted under certain conditions. 3) On-farm and Home-Garden conservation: a) On-farm conservation involves in maintenance of traditional crop varieties with in traditional agricultural systems. b) Home-Garden conservation is a small scale conservation like garden, orchard, etc Advantages: a) It provides an opportunity to the species to exist conditions of envt with adopted life form. b) It reduces the conservation effort, so this method is convenient and time economic. 12

13 Disadvantages: a) It requires enormous space. b) A large number of producers and consumers to be protected to maintain the food chain. c) Investment is huge. d) Risk in maintenance. Ex-Situ conservation of Biodiversity It involves maintenance and breeding of endangered plant and animal species in zoos, gardens, nurseries and laboratories. The identification of endangered species is the only risky task. Methods: 1) Long-Term captive breeding: It involves capture, maintenance and breeding in captivity on long term basis of endangered species. Captive breeding is the only way to preserve endangered species. This is the method applicable for species which have lost their habitats and forced out to extinction. 2) Short-Term propagation and release: The endangered species are maintained and bred in captivity under human care, then they released in the wild habitat. This method is good for the species whose population is declined temporarily. 3) Animal translocations and animal re-introduction: If a particular species is endemic to a particular place, then moving the population to some other place may be the best way of saving it from being lost. To conserve and protect wild species, the animals can also be re-introduced into an area from which they declined. 4) Seed Bank: The rare plant species can be conserved by preserving its seeds. By germinating the seed it is possible to yield their younger ones. The places where the seeds are stored are called as seed banks or germination centre. 5) Reproduction Technology: It includes artificial insemination, embryo transfer technology and cryo-preservation of gametes and embryos. Advantages: a) It the best of method of conservation of endangered species. b) It conserves the population of endangered species. Disadvantages: a) It is very expensive. b) As the wildlife population is more, it is very difficult to conserve. c) The captivity breeding and maintenance results in adverse genetic and behaviourial consequences for the species. Question Bank Part B (Frequently/Previously asked semester questions) 1. Explain the structure, function and energy flow of an ecosystem. 2. Explain the following terms: a) Ecological succession b) Food chain c) Food web d) Ecological pyramid 3. Explain the features and functions of 13

14 a) Forest ecosystem b) Grassland ecosystem c) Aquatic ecosystem d) Desert ecosystem 4. Discuss in detail: conservation of biodiversity. 5. Explain the bio-geographical classification of India. Part A (Frequently/Previously asked semester questions) 1. Define the term Biodiversity. Write down the three different levels of Biodiversity. 2. State the significance and scope of environmental education. 3. What are the characteristics of the Desert ecosystem? 4. Define environmental science. 5. Name any four ecosystems. 6. Enumerate the human activities which destroy the biodiversity. 7. Define the terms producers and consumers. 8. What is meant by genetic diversity? 9. Distinguish between primary and secondary consumer. 10. Enumerate the structural and functional elements of ecosystem. 11. Explain endangered species. 12. Explain ecological succession. 13. Write any two functions of forests. 14. What are the classifications of biotic components of ecosystems? 15. What is food chain and food web? 16. Explain threatened and endangered species. 17. What is ecosystem? 18. What are autotrophs and heterotrophs? Give examples. 19. Define ecological succession and mention its types. 20. What are the two important bio-diversity hot spots in India? 21. How would environmental awareness help to protect our environment? 22. Give flow chart of energy flow in an ecosystem. 23. Name any two extinct species of India. 24. Write the role of decomposers in ecosystem. 25. Give the causes for endangerment of species. 26. What are the different components of an ecosystem? 27. Define Genetic diversity and species diversity. *************************************************** Prepared By: Dr. M. Manivannan. M.Sc., M.Phil., Ph.D Asst Professor / Department of chemistry CNCET. 14