Environmental Science Textbook (PDF) - SSN Engineering College

New Edition A Text Book of ENVIRONMENTAL SCIENCE As per the SSN College of Engineering (Autonomous) Syllabus For I Semester B.E. and B.Tech. Students COMMON TO ALL BRANCHES Dr. ARUN LUIZ T Dr. M. MAHALAKSHMI Dr. A. M. SHANMUGHARAJ Dr. A. MURUGESAN Department of Chemistry SSN COLLEGE OF ENGINEERING Kalavakkam, Chennai DHANAM PUBLICATIONS Chennai - 600 042 Phone: 044 - 4303 6502 Mobile: 99406 41496 / 98401 25695 Email [email protected] © All rights reserved with the Publisher / Authors First Edition: January 2025 This book or part thereof should not be reproduced in any form without the written permission of the author and publisher Price: Rs. ISBN: For copies contact DHANAMPUBLICATIONS No.18, 3rd Main Road DhandeswaramNagar, Velachery, Chennai-600042. Laser Typeset at JV Computers, No.62, Pillaiyar Koil Street, Kanagam, Chennai 600 113. Printed at: Sankar Printer, Velachery, Chennai – 600 042 PREFACE The increasing environmental challenges of the modern world require a deeper understanding of the interconnectedness between humanity and nature. This book, designed for undergraduate engineering students, introduces the essentials of Environmental Science, emphasizing the urgent need for conservation, sustainability, and innovative technological solutions to tackle environmental issues. As per the directions from The Supreme Court of India, UGC has made mandatory a course of Environmental science for undergraduate students in Indian universities. This book is the outcome of our rich teaching experience gained over the years. The book is written according to the new syllabus of SSN Engineering College (Autonomous) 2024. Through its structured units, the book explores foundational concepts, from understanding ecosystems and biodiversity to analyzing the current environmental crises we face. It provides insights into managing natural resources, addressing pollution, and exploring cutting-edge approaches like Artificial Intelligence, Internet of Things, and Geographic Information Systems to reduce environmental stress. The content also highlights the critical importance of Sustainable Development Goals (SDGs), offering students the knowledge to contribute to a more equitable and resilient future. Real-world examples, case studies, and field trips have been included to connect theoretical concepts to practical applications, fostering a hands-on learning experience. By the end of this course, students will not only gain awareness of environmental science but also develop the skills to engineer solutions that align with sustainable practices. It is our hope that this book inspires readers to become proactive contributors in creating a greener and healthier planet. Authors thank SSN Management for constant encouragement and support. - Authors SSN ENGINEERING COLLEGE (AUTONOMOUS) Regulation - 2024 COURSE COURSE TITLE L T P E C CODE ENVIRONMENTAL SCIENCE 3 0 0 0 1 (Common to all B.E/B.Tech. programs) COURSE OBJECTIVES:  To develop a better understanding of human relationship with environment  To explain the importance of conservation of resources  To create awareness on pollution and environmental degradation  To acquire knowledge on sustainable development  To apply technical skills for solving environmental problems UNIT I FUNDAMENTALS OF ENVIRONMENTAL SCIENCE 9 Definition, scope and importance of environment and function of an ecosysytem-Terrestrial(Forest)-Aquatic(lake)-ecological succession – ecological pyramids – Biodiversity in the environment- Types and Values of biodiversity- hot-spots of biodiversity – threats to biodiversity-In-situ and ex- situ conservation of biodiversity. Field Trip: Zoo/Botanical Garden UNIT II NATURAL RESOURCES 9 Forest resources: deforestation– Water resources: over- utilization of surface water and, conflicts over water, dams-benefits and problems – Mineral resources: environmental effects of mining– Food resources: fertilizer-pesticide problems– Energy resources: Need for renewable energy sources, use of alternate energy sources (Wind, Solar, Geothermal)– Land resources: soil erosion and desertification UNIT III CURRENT ENVIRONMENTAL ISSUES 9 Planetary boundaries - Environmental issues– causes, effects and control measures of Pollution of (a) Air (Smog, acid rain, climate change, ozone layer depletion) (b) Water (waste water treatment) (c) Soil Solid waste management -wasteland reclamation, Electronic waste management Population explosion- Population growth among nations-– Disaster management Case Study-Air Pollution in Delhi, Cooum river pollution, Chennai municipal waste management Field Trip: Wastewater Treatment Plant UNIT IV SUSTAINABLE DEVELOPMENT (SD) 9 Origin, purpose, and importance of the SD- Key issues and challenges of Environmental sustainability- 2030 Agenda for Sustainable Development- Indicators and metrics for tracking progress of sustainable development- Circular economy Rainwater Harvesting-Principles - Green Buildings-Advantages of green buildings over conventional buildings-smart city - Electric and Hybrid Electric Vehicles (HEV) UNIT V ENGINEERING INTERVENTIONS TO REDUCE ENVIRONMENTAL STRESSES 9 Role of technology in environment studies and human health- Use of Artificial Intelligence and Internet of Things- Environment database management system. Real-time data collection and analysis- Environmental Modelling and Simulation- Geographical Information Systems (GIS)-Remote Sensing- satellites and sensors-Use of Drones of Aerial mapping and Surveying. TOTAL: 45 PERIODS Course Outcomes: Upon successful completion of the course, students will be able to CO1: Acquire the basic concepts of ecosystems; understand the importance of biodiversity and conservation strategies (BL-L2). CO2: Develop knowledge on natural resources and equitable use of natural resource (BL: L2). CO3: Analyse the current environmental problems and its plausible solutions (BL: L2) CO4: Explain the concept of sustainable development, its importance and key challenges in implementation of sustainability goals (BL: L2) CO5: Describe the role of technology for assessment and management of environment and human health (BL: L2). Text Books: 1. Anubha Kaushik and Kaushik, C. P. "Environmental Science and Engineering", New Age International Publishers, 14thEdition, 2014. 2. Benny Joseph, ‘Environmental Science and Engineering’, Tata McGraw-Hill, New Delhi, 2006 References: 1. Gilbert M. Masters, ‘Introduction to Environmental Engineering and Science’, 2nd edition, Pearson Education, 2004. 2. Tyler Miller G., and Scott E. Spoolman, “Environmental Science”, Cengage Learning India PVT, LTD, Delhi, 2014. 3. M.H. Fulekar, Bhawana Pathak and R.K. Kale, ‘Environment and Sustainable Development’ Springer Nature, 2013 CO to PO Mapping COs POs PSOs 1 2 3 4 5 6 7 8 9 10 11 12 1 3 2 3 3 3 1 1 1 4 2 3 1 1 1 5 2 3 1 1 1 CONTENTS Page Nos. UNIT -1 Fundamentals of Environmental Science………………………….1.1- 1.49 UNIT-2 Natural Resources......................................................................... 2.1 - 2.52 UNIT-3 Current Environmental Issues...................................................... 3.1 - 3. 79 UNIT-4 Sustainable Development (SD)..................................................... 4.1 - 4.31 UNIT-5 Engineering Interventions to reduce Environmental Stress.......... 5.1 – 5.35 Fundamentals of Environmental Science 1.1 UNIT I FUNDAMENTALS OF ENVIRONMENTAL SCIENCE Definition, scope and importance of environment and function of an ecosysytem - Terrestrial (Forest)-Aquatic(lake) - ecological succession – ecological pyramids – Biodiversity in the environment- Types and Values of biodiversity- hot-spots of biodiversity – threats to biodiversity-In-situ and ex-situ conservation of biodiversity. Field Trip: Zoo/Botanical Garden 1.1. ENVIRONMENT STUDIES: DEFINITION, SCOPE AND IMPORTANCE The word Environment is derived from the French word “Environ” which means “surrounding”. Hence, everything surrounding us is called "Environment". The environment creates favourable conditions for the existence and development of living organisms. The survival of any organism requires a steady supply of materials and removal of waste products from its environment. Thus, Environment is the sum total of inter relationships that exists among living organisms and non- living things like air, water and land. Environmental science is an interdisciplinary area that integrates physical, chemical and biological sciences. It deals with the study of the environment, problems faced by the environment and their solutions. Environment 1.2 Environmental Science Natural resources are over exploited by the present generation without worrying about future. It is our responsibility to ensure that future generation should not be affected. The deterioration of the environment in the past few decades gave a wakeup call for scientists, policy makers, and common public across the world. It made people realize several environmental problems—such as pollution, global warming, ozone layer depletion, acid rain, deforestation, desertification etc. Environmental education plays a crucial role in educating people about the current situation and future scenario. Thus, the need and scope of environmental studies have become more significant in the current scenario due to the following reasons:  Environment issues being of international importance Most of the environmental issues are not confined to one region or locality, it is of international importance. Some of the issues include pollution, global warming, loss of biodiversity, ozone layer depletion etc. Several global organizations were formed to deal with these issues.  Problems associated with industrialization and development Rapid growth of science and technology resulted in industrialization. The purpose of economic development in any region is to provide opportunities for improved living and jobs to people. This rapid industrialization has caused severe environmental damage due to air pollution, water pollution, soil contamination and habitat destruction.  Population explosion The current world population is 7.7 billion as of December 2018 according to the recent survey from United Nations. This population explosion will cause depletion of all natural resources.  Natural resources: Conservation and management Over exploitation of natural resources is a big concern. Major natural resources like water, forest, food, energy etc are over utilized. These resources has to preserved, protected and utilized wisely. Environmental education helps to adopt Fundamentals of Environmental Science 1.3 best practices in strategic planning, and opportunities for collaboration and public participation around resource-based issues.  Ecology and Biodiversity The Ecology and Biodiversity Group investigates the mechanisms that regulate biodiversity and allow for the maintenance of ecosystem functioning in our changing world. Ecology and Biodiversity give essential knowledge to understand nature’s complex connections and the relationships between species, their environment and climate.  Environmental pollution and control Environmental pollution is one of the serious problems in most of the mega cities of the world, especially in developing countries. Population growth and migration of rural population have resulted in environmental pollution. Methods to propagate environmental awareness Education can give right knowledge on how natural environment functions, and how human beings can deal with behavior and ecosystems for sustainability. o Environmental Awareness through Adult Education: The aim of adult education should be to create a collective action in solving the environmental problems. The new types of complex environmental problems require understanding and hence a new approach to adult education. o Among students through education: Environment Education, Awareness and Training (EEAT) is a central sector Scheme of the Ministry of Environment, Forest and Climate Change launched to promote environment awareness amongst school and college level students. It aims to create awareness on various aspects of environment, climate change and connect to nature and is being implemented across the county through formal and informal education. o Among people through mass-media: Mass- media can play a vital role in creating peoples’ awareness about environment and conservation of natural resources. It can serve this purpose by means of its multi-channel regional and 1.4 Environmental Science network service comprising programs such as talks, interviews, plays and documentaries etc. o Among the planners, decision-makers and leaders: It should involve planning, action, and communication of the specific idea concerned related to environmental protection. It should involve short-term and long-term measures, which can be achieved by arranging training programme through workshops, seminars, conferences, etc. o Publication of environment-related resource material: In the form of books, booklets or pamphlets educational awareness can be given. o Awareness through Public participation: There is a need for public participation due to the recent change in sources of environmental problems. World Environment Day is celebrated every year on June 5th to create a global awareness for environmental protection. The United Nations Conference on the Human Environment was organized from 5–16 June 1972 in Stockholm, Sweden. This was the first attempt made by global community to deliberate on environmental protection. Since 1972, World Environment Day is celebrated on June 5. Name Date World Water Day March 22 Earth Day April 22 World Environment Day June 5 World Population Day July 11 World Biodiversity Day May 22 Fundamentals of Environmental Science 1.5 Recent Nobel Prize (Peace) winners for Environment related issues Organization / Person Year Work International Campaign to For humanitarian work for Abolish Nuclear Weapons 2017 campaigning against abolishing (ICAN) nuclear weapons Kailash Sathyarthi (India) For struggle against suppression and Malala Yousafzai 2014 of children and promoting right (Pakistan) for children education Organization for the For its extensive efforts to prohibition of chemical 2013 eliminate chemical weapons weapons (OPCW) All Gore and For their efforts to disseminate Intergovernmental panel on 2007 knowledge about man made climate change (IPCC) climate change. 1.2. ECOSYSTEMS The term Ecology is derived from the Greek words Oikos (home) + logos (study). Ecology deals with the study of organisms in their natural habitat and their interactions with their surroundings. The surroundings consist of other living organisms (biotic) and physical (abiotic) components. Ecosystem: An ecosystem is a group of biotic communities or species interacting with one another and with their non-living environment exchanging energy and matter. Ecology: The study of plants and animals in their relation to each other and with their environment. Ecology is the study of ecosystems. 1.6 Environmental Science Important Terms: Biosphere: Part of Earth that supports life, including the top portion of Earth's crust, the atmosphere, and all the water on Earth's surface Biotic: Living component of the environment Abiotic: Non-living component of the environment Habitat: Place where an organism lives and that provides the types of food, shelter, moisture, and temperature needed for survival Niche: In an ecosystem, refers to the unique ways an organism survives, obtains food and shelter, and avoids danger Limiting factor: Anything that can restrict the size of a population, including living and non-living features of an ecosystem, such as predators or drought Carrying capacity: Largest number of individuals of a particular species that an ecosystem can support over time Organism: One individual of any living thing residing in a particular area Population: All the organisms that belong to the same species living in a community Community: All the populations of different species that live in an ecosystem Biome: Large geographic areas with similar climates and ecosystems Types of Ecosystem: (a) Natural Ecosystes: These ecosystems are capable of operating and maintaining themselves under natural conditions. A classification based on their habitat can further be made as:  Terrestrial ecosystems: This ecosystem is related to land and the type of vegetation. Examples: Forest, Grassland and Desert ecosystem.  Aquatic ecosystems: This ecosystem is related to water. It is further classified into two types based on salt content. Fundamentals of Environmental Science 1.7 a) Fresh water ecosystem: Running water ecosystem. Examples: River, Streams Standing water ecosystem: Examples Pond, Lake b) Marine ecosystem: Examples Ocean, Sea or Estuary (b) Artificial Ecosystem: These are maintained by man. These are manipulated by man for different purposes, Examples: croplands, artificial lakes and reservoirs, townships and cities. STRUCTURAL ASPECTS OF ECOSYSTEMS Two major structural components of ecosystem are (i) Abiotic components (ii) Biotic components (i) Abiotic components Non-living components (physical and chemical) of an ecosystem collectively are called abiotic components. Main abiotic factors of the ecosystem are Climatic factors: solar radiation, temperature, wind, water currents, rainfall. Physical factors: Light, fire, pressure, geomagnetism (ii) Biotic components Living organisms or living members in an ecosystem form biotic components. It includes plants, animals and microorganisms present in an ecosystem. The biotic components of an ecosystem can be classified according to their mode of energy acquisition. These consists of three types (a) Producers (b) Consumers (c) Decomposers or reducers 1.8 Environmental Science (a) Producers Producers are mainly the green plants, which can synthesize their own food by the process of photosynthesis. In the presence of sunlight and chlorophyll, green plants covert CO2 and water into starch (food). They are also known as photo autotrophs (self-nourishing). They fix energy from the sun and store it in complex organic compounds. Examples: Green plants, algae, some bacteria etc. Simple inorganic compounds → Photoautotrophs → Complex organic compounds Photosynthesis Certain microorganisms produce food by the oxidation of certain chemicals in the absence of sunlight. They are known as chemosynthetic organisms or chemo-autotrophs (Chemo = chemical, auto = self, troph = nourishment). Chemo synthesizers are bacteria. Generally they oxidize, reduced inorganic substances (typically sulfur and ammonia compounds) in absence of sunlight produce organic compounds. Fundamentals of Environmental Science 1.9 (b) Consumers Consumers are also known as Heterotrophs (other-nourishing) and cannot produce their own food directly from sunlight and inorganic compounds. Consumers are organisms which cannot prepare their own food but depend on producers or other organisms for food. Consumers convert complex organic compounds into simple inorganic compounds.  Primary consumers or Herbivores: They feed directly on green plants. They are also known as plant eaters. Examples: Rabbit, deer, sheep, insects etc.  Secondary consumers or carnivores: They feed on herbivores, hence called secondary consumers. Examples: Small fish, frog  Tertiary consumers: They feed on secondary consumers Examples: Big fish, snake  Omnivores feed on both plants and animals. Examples: Humans, rat, fox, many birds  Detritivores (Detritus feeders or Saprotrophs): They feed on dead organisms, plant or animal matter. Examples: Earth worms, fungus, termites, ants etc. (c) Decomposers Decomposers derive their nutrition by decaying dead plants and animals. They break down the complex organic molecules to simpler molecules. Examples: Various bacteria and fungi. FUNCTIONS OF ECOSYSTEMS Major functions of ecosystems are the following: Food chain, food webs and trophic structure (Ecological pyramids) Energy flow in ecosystem Cycling of nutrients (Biogeochemical cycles) Soil formation 1.10 Environmental Science Climate, flood and disease regulations Water purification Primary and Secondary production Ecosystem development and regulation FOOD CHAINS AND FOOD WEBS FOOD CHAIN The transfer of energy within the ecosystem (among various levels) by a sequence of eating and being eaten is known as food chain. In any food chain energy flows from producers to herbivores to carnivores. Some common examples of simple food chains are: (i) Grass → grasshopper → Frog → Snake → Hawk (Grassland ecosystem) (ii) Phytoplanktons → Zoo plankton → small fish → Large fish (Marine ecosystem A food Chain Some features of food chain  A food chain is always straight (unidirectional flow of energy).  Usually 80 to 90% of potential energy is lost as heat when energy is transferred from one level to another.  Shorter food chains provide greater available energy and vice-versa.  Most food chains have no more than four or five links.  If any of the intermediate steps in the food chain is removed, other succeeding links of food chain will be affected. Fundamentals of Environmental Science 1.11 Types of food chain I. Grazing food chain: Here, green plants (primary producers) are eaten by grazing animals and they are further eaten by carnivores. This type is food chain is found common in grassland ecosystem and grassland ecosystem. Examples: Grass → Rabbit → Fox II. Detritus food chain: It starts with dead organic matter. Organic matter is broken down into simple nutrients by bacteria and fungi. Examples: Leaf litter  Algae  Crabs Small carnivorous fish III. Parasitic food chain: In parasitic food chain, producer or consumer has parasites. These parasites extract food from them. However, the energy transfer through this kind of food chain is not significant. Examples: Producer Herbivores Parasite Hyperparasites Trees Fruit eating birds Lice and bugs Bacteria and fungi FOOD WEB Many organisms will depend upon more than one source of food. Most consumers feed on more than one type of organism and most organism are eaten by more than one type of consumer. A network of food chains which are interconnected is called food web. This is also called the ‘web of life’ as it shows many interrelationships in nature. A food web 1.12 Environmental Science Significance of food chain and food web  Food chain/web explains the feeding relationships and interaction between organisms in any ecosystem.  To understand the energy flow mechanism and matter circulation in ecosystems.  To track movement of toxic substances and the problem of 'Biological magnification' in the ecosystem.  To analyse the link between biological diversity and stability of an ecosystem. FOOD CHAINS AND FOOD WEBS - A COMPARISON Food Chain Food Web Simple structure Quite complex structure Unidirectional Multi directional Less number of organisms Large number of organisms Food chain is a single strand of Food web will show many food different Levels of energy transfers. Chains in a particular ecosystem. 1.3. ECOLOGICAL PYRAMIDS Ecological pyramid is a graphic representation of trophic levels and functions of an ecosystem. Ecosystem characteristics such as number, energy and biomass show a regular decrease as it moves to next trophic level and the figure obtained is a pyramid. Most ecological pyramids begin at the bottom with the producers and proceed through different trophic levels. Fundamentals of Environmental Science 1.13 Typical Ecological Pyramid Ecological pyramids are of three general types as under: (i) Pyramid of numbers: It shows the number of individual organisms at each trophic level. (ii) Pyramid of energy: It shows the rate of energy flow and/or productivity at successive trophic levels. (iii) Pyramid of biomass: It shows the total biomass present in each tropic level in the food chain. (i) Pyramid of numbers Pyramids of numbers show the relationship between producers, herbivores, and carnivores at successive trophic levels in terms or their numbers. Shape of the pyramid varies from ecosystem to ecosystem as the number of organisms at each level is variable. Upright, partly upright, and inverted are the three types of pyramids of numbers. An aquatic ecosystem is an example of an upright pyramid where the number of organisms becomes lesser and lesser higher up the pyramid. A forest ecosystem is an example of a partially upright pyramid, as fewer producers support more primary consumers, but there are less secondary and tertiary consumers. An inverted pyramid of numbers is one where the numbers of organisms are higher on 1.14 Environmental Science the top of the pyramid. Parasitic food chain shows inverted pyramid of numbers. In parasitic food chain, one primary producer supports numerous parasites which support still more hyper parasites. 10 Tertiary Consumers Snakes Producers 100 Frogs Secondary Consumers Snakes Producers 1,000 Grasshoppers Primary Consumers Producers 10,000 Grass Producers Upright Pyramid of numbers in grassland ecosystem Hyperparasites 1000 Parasites 1000 Herbivores 100 Producers 10 Partially upright pyramid of numbe Inverted pyramid of number (ii) Pyramid of energy Pyramid of energy represents graphically the amount of energy consumed by each tropic level. It shows the energy flow in the ecosystem. An energy pyramid is always upright. Fundamentals of Environmental Science 1.15 In accordance to second law of thermodynamics, no organism obtains 100% of energy from the plant or animal that it eats. In fact, there is a huge loss of energy (about 90%) in the form of heat, respiration etc. Only 10% of the energy passes on to the next higher level. Features: Pyramid of energy is always upright and vertical. Energy flow in different trophic levels can be easily understood with the help of an energy pyramid. From the energy pyramid, the total energy is minimum as the highest trophic level and is maximum at the lowest trophic level. A lot of energy is lost in the form of heat and respiration etc between energy levels. Pyramid of energy (iii) Pyramid of biomass Biomass is renewable organic (living) material. A pyramid of biomass is a graphical representation of the amount in biomass at different trophic levels. It is measured in grams per meter2 or calories per meter2. It shows the decrease in biomass in each tropical level from base to apex. There are two types of biomass pyramids: upright and inverted. An upright pyramid is one where the combined 1.16 Environmental Science weight of the producers is larger than the combined weight of consumers. An example is a forest ecosystem. An inverted pyramid is one where the combined weight of producers is smaller than the combined weight of consumers. An example is an aquatic ecosystem. Upright Pyramid of biomass Inverted pyramid of biomass 1.4. ENERGY FLOW IN THE ECOSYSTEM Single Channel Energy Model The ultimate source of energy for all ecological systems is the sun. A part of this energy is absorbed by the biosphere and a part of energy is reflected back to the space (lost). When solar energy strikes the earth, only about 10 per cent of this energy gets absorbed by the green plants, and is subsequently transformed into food energy. The food energy is transmitted among a series of organisms via food chain. On the death of organism, decomposers act on the dead bodies and recycle the essential nutrients. As energy flows through the food chain, lot of energy is lost at every trophic level. The loss of energy takes place through respiration, loss of energy in movement, hunting and other activities. It is estimated that nearly 90% energy is lost at every energy level. That is, the energy transferred from one trophic level to the other is only about 10% (10% law). Fundamentals of Environmental Science 1.17 Energy flow in the ecosystem The flow of energy in an ecosystem is always unidirectional. This means that it flows from the producer level to the consumer level and never in the reverse direction. This flow of energy is governed by two laws of Thermodynamics. Ist law of Thermodynamics states that energy can neither be created nor be destroyed but it can be transformed from one form to another. 2nd law of Thermodynamics states that a part of energy is lost when it is transferred from one level to another. Features:  Unidirectional flow of energy  At each trophic level, there occurs progressive decrease in energy.  90% of the energy captured from the previous trophic level is lost as heat to the environment and only 10 percent is made available to the next trophic level. Nutrient cycles (Biogeochemical cycles) Elements that are essential for survival of both plants and animals are called nutrients. 1. Macronutrients: Elements that are required in large amounts Examples: Carbon, Oxygen, Calcium, Magnesium, Phosphorus 2. Micronutrients: Elements that are needed in small amounts Examples: Zinc, Copper, Cobalt, Selenium 1.18 Environmental Science Nutrients are always circulated to and fro within the environment. This cyclic exchange of nutrient material between the living organisms and their non- living environment is called biogeochemical cycle. The common biogeochemical cycles are Hydrological cycle or water cycle, Carbon cycle, Oxygen cycle, Nitrogen cycle, Phosphorus cycle. Some are gaseous cycles like carbon (as carbon dioxide), oxygen, nitrogen, etc. A few are sedimentary cycles like sulphur, phosphorus, etc. 1.5. ECOSYSTEM PRODUCTIVITY Primary production Primary productivity (PP) of an ecosystem is defined as the rate at which incident solar energy is converted into food (starch) by photosynthesis. Primary production depends on solar radiation, availability of water, nutrients, types of plants, chlorophyll content etc. To a lesser extend primary production can happen in the absence of sunlight by chemosynthesis. Gross primary production (GPP): The total amount of CO2 that is used up by plants in photosynthesis or total amount of energy captured by the plants Net primary production (NPP): Total energy converted into organic matter excluding respiration NPP = GPP – Respiration Net primary production is thus the amount of energy stored by the producers and potentially available to consumers and decomposers. Secondary production The amount of food stored by the consumers or total amount of energy captured is known as secondary production. A part of this energy stored is transmitted to the next trophic level. 1.6. ECOLOGICAL SUCCESSION Ecological succession is defined as the orderly changes that happens in a community structure and function over a period. Quite often it is observed that one type of community is totally replaced by another over a period of time. In other Fundamentals of Environmental Science 1.19 words, a community evolves slowly from a simple community to a much complex community. Generally, climax community is reached in a period of few hundreds of years. The community which established first is known as Pioneer Community. The communities which are transitory and undergoing changes are known as Seral stages or Seres. The final and mature community established at the end is known as climax community. Types of ecological succession Primary succession: It involves the gradual establishment of biotic communities on a lifeless ground. a) Hydrarch: Establishment starts in a water body like pond or lake. This type of succession begins with the formation of colonies of phytoplankton. b) Xerarch: Establishment starts in dry area where soil is devoid of water and minerals. Usually this begins with the formation of lichen on the surface of rocks. Secondary succession: This involves the establishment of biotic communities in an area, where some type of biotic community is already present. Process of Succession The process of succession takes place in a systematic order of steps as follows: (i) Nudation: It is the formation of a bare area without any life form. This bare area may be created due to landslides, volcanic eruption, overgrazing, agricultural/ industrial activities etc. (ii) Invasion: Nudation is followed by invasion. It is the successful establishment of one or more species on a bare area. Seeds, spores etc are carried by wind, water, insects or birds. These seeds germinate and small plants begin to grow. Slowly, these pioneer species increase in number and form groups. (iii) Competition: Competition results when the number of individuals increases. Competition can be between different species or within the same species. Competition happens for space, water and nutrition. Survival of the fittest takes place. 1.20 Environmental Science (iv) Reaction: Due to the influence of the environment, some modification in the existing species will be created. The available resources are suitable for certain species and unsuitable for some other species. This reaction will result in the replacement of some species by another leading to several seral communities. (v) Stabilization: This is also known as the climax where the final stable community is formed. It may take several years to attain a stable community. Process of Ecological Succession Importance of ecological succession It provides information, how smaller community develop into a climax community. Growth rate of one or more species can be suitably checked by adjusting various environmental parameters. It helps in afforestation and forest management programs. Ecological succession-A case study On May 18, 1980 a major volcanic eruption occurred at Mount St. Helen’s, in Washington, United States. Eruption resulted in the complete transformation of the landscape. Lava flew and hardened on the land. Eight years since eruption only one kind of plant species were found. After fifteen years, nearly 17 species were found. Today, Mount St. Helen’s is in the process of secondary succession. Fundamentals of Environmental Science 1.21 1.7. MAJOR ECOSYSTEM TYPES The major types of ecosystem are a) Terrestrial ecosystem: This is an ecosystem found only on landforms. Example: Forest, Grassland, Desert ecosystem. b) Aquatic ecosystem: It is an ecosystem in a body of water. Example: Fresh water ecosystem (pond, lake, stream, river etc), marine ecosystem (Estuarine, Ocean etc) TERRESTRIAL ECOSYSTEM: FOREST ECOSYSTEM Forest ecosystem predominantly consists of trees, along with herbs, shrubs, creepers, mosses, lichens, bacteria etc. Wide variety of animals and birds are also seen. Depending upon the prevailing climatic conditions forests can be of various types a) Tropical Rain Forests: They are evergreen forests found near the equator (tropics). These forests are found in areas which are characterized by high temperature, high humidity and high rainfall. b) Tropical Deciduous Forests: These forests are found a little away from the equator and are characterized by a warm climate the year round. Different types of deciduous trees are found here, which lose their leaves during dry season. c) Tropical Scrub Forests: They are found in areas where the dry season is even longer. Here there are small deciduous trees and shrubs. d) Temperate Rain Forests: They are found in temperate areas with adequate rainfall. These are dominated by coniferous trees like pines, firs, redwoods etc. e) Temperate deciduous forests: They are found in areas with moderate temperatures. 1. Abiotic components (Non-Living Components) Abiotic components of forest eco system include basic inorganic and organic compounds of the environment or habitat of the organism. 1.22 Environmental Science a) Inorganic Components: Inorganic components of an ecosystem are carbon dioxide, oxygen, water, nitrogen, calcium etc. Most of them are involved in matter cycles (biogeochemical cycles). b) Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids, amino acids etc. All of these are synthesized by the biota (flora and fauna) of an ecosystem and are reached back to ecosystem as their wastes, dead remains, etc. c) Other physical factors: Climate, temperature, light, soil etc., are other abiotic components of the eco-system. 2. Biotic Components (Living Components) a) Producers Producers include green plants like herbs, shrubs and trees. These prepare food (starch) from water and CO2 in presence of sunlight and chlorophyll. Nature and number of plants associated may vary according to the location. Examples: Grass, trees etc. b) Consumers  Herbivores (plant eaters): Herbivores feed directly on producers and hence also known as Primary Consumers. Example: rabbit, deer, squirrel, insects.  Carnivores (meat eaters): They feed on other herbivores. If they feed on herbivores they are known as Secondary Consumers. Example: frog, fox. If they feed on other secondary consumers, they are known as tertiary consumers. Example: Snake, Lion, Tiger. c) Decomposers: Decomposers break down complex compounds present in dead tissues of producers and consumers into simple substances. These simple compounds can be easily consumed by green plants. Example: Earthworms, Bacteria, Fungi etc. Fundamentals of Environmental Science 1.23 A forest ecosystem A typical forest food chain: Grass, Trees (producer) → Deer (herbivore) → Tiger (carnivore) Functions of Forest Ecosystem:  Enhances water resources in both quantity and quality.  Helps in storage capacity of water.  Ecological cleansing action  Maintain hydrological cycle and nutrient cycles.  Provide shelter to wildlife.  Prevent soil erosion. AQUATIC ECOSYSTEM: LAKE ECOSYSTEM Lake is a much larger fresh water body when compared to pond. Depending upon the depth and distance from the shore, lake consists of four different zones. 1. Littoral zone: The littoral zone is the part of the lake closest to the shore. It is a shallow water zone where light penetrates to the bottom and supporting rooted plants and bottom-dwelling animals. 2. Limnetic zone: This is the zone next to littoral zone where moderate light penetration takes place. Photosynthesis mainly occur in this zone. 1.24 Environmental Science 3. Profundal zone: This is the zone where sunlight doesn’t reach. It is dark and cold. Photosynthesis does not occur here. 4. Benthic zone: The bottom most part of the lake is benthic zone. This zone provides many nutrients to the plants because it has large volume of sediments and it contains many nutrients. Here light penetration is negligible. Different zones of lake The functional components of a lake ecosystem 1. Abiotic Components (Non-Living Components) Abiotic substances of Lake Ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. a. Inorganic Components: Inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, salts etc. b. Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. c. Physical factors: Climate, temperature, sunlight, soil etc., are other abiotic components of the ecosystem. 2. Biotic Components (Living Components) a) Producers Producers are of two types 1. Larger rooted and floating vegetations together termed Macrophytes 2. Microscopic floating algae called Phytoplanktons. Fundamentals of Environmental Science 1.25 Phytoplanktons are available up to the depth of water where light penetrates. Example: Filamentous algae like Ulothrix, Spirogyra, Oscillatoria and minute floating plants like Microcystis. Macrophytes include plants like lotus, hydrilla etc. Floating plants are characterized by light hollow stem, wax coated leaves. Phytoplanktons 2 b) Consumers Consumers of pond (lake) ecosystem are heterotrophs which depend for their nutrition on other organisms. Zooplanktons form primary consumers which feed on phytoplankton. Nectic animals like insects, beetles, small fishes form secondary consumers as they feed on zooplanktons. Benthic animals like snakes, big fishes live on nectic animals form tertiary consumers. c) Decomposers Bacteria, fungi are major decomposers. Generally, the decomposers either live in the soil layer beneath water or in the mud. They act on dead and decayed organic matter of plants and animals and supply nutrients to the producers. A typical lake food chain: Phytoplankton Zooplankton Small fish, Big fish, Snake (Producer) (Herbivore) (Carnivore) 1.26 Environmental Science 1.8. BIODIVERSITY Biodiversity is the diversity among various life forms. It is a measure of the variety in flora and fauna present in various ecosystems. Thus, the variety and variability of life on earth is known as biodiversity. It is an umbrella term for the degree of nature’s variety. Biodiversity can refer to genetic variation, ecosystem variation, or species variation. Levels (types) of Biodiversity Biodiversity is generally classified into three types. These three levels result in the complexity of life on earth. 1. Genetic diversity Genetic diversity refers to the variation of genes present within the species. Genes are responsible for both the similarities and differences between the organisms. Example:  Dog: pug, bull dog, Dalmatian, Alsatian etc.  Tiger: Royal Bengal tiger, Siberian tiger, White tiger etc.  Elephant: Indian elephant and African elephant.  Mango: Malgova, Alphonso, Banganapalle  Rice: Basmathi, Jaya, IR8 2. Species diversity: Species is a group or class of animals or plants which have some common characteristics which distinguish it from other groups or species. Species diversity refers to the variation among species in a community. Example:  Plant species: Apple, mango, orange, wheat, rice etc.  Animal species: Lion, cow, deer, cat etc. Fundamentals of Environmental Science 1.27 There are approximately 1.8 million different species classified on Earth. Of these nearly 1 million are insects. Every year, approximately 13,000 more species are being discovered. 3. Community or Ecosystem Diversity: Ecosystem diversity is the variation in the biological communities in an ecosystem. There is a variation in the structure and functions among different ecosystems. Example: Forest ecosystem and pond ecosystem are quite diverse. 1.9. VALUES (IMPORTANCE) OF BIODIVERSITY Biodiversity has great values in terms of its commercial utility, ecological services, social and aesthetic values. The values of biodiversity are classified into two categories, namely 1. Direct alues 2. Indirect values 1. Direct values These are the uses that can be directly related to biodiversity. The two types of direct values are a) Consumptive use values b) Productive use values a. Consumptive use values The products due to biodiversity are consumed directly. Example: Food, fuel, drug etc. Food: A variety of plants are consumed by human beings as food. Example: Rice, wheat, fruits, pulses etc Drugs and medicine: Drug Penicillin is obtained from Penicillium fungi, Quinine, drug for malaria is obtained from plant cinochona, Anticancer drug Vinblastine is obtained from plant periwinkle. Ayurveda uses many medicinal plants as drugs. Fuel: Wood is widely used as fuel in many rural areas. 1.28 Environmental Science High consumptive use values on resources may lead to deforestation, loss of biodiversity etc. b. Productive use values Productive value refers to products which are commercially harvested or used and sold in a market. These products may be derived from plants or animals and many industries directly depend upon biodiversity products. Animal products Animal product Animal/Insect Wool Sheep Musk Musk deer Honey Honey bee Silk Silk worm Plant products Plant product Industry Paper and pulp industry, Wood plywood industry etc Cotton Textile industry Fruits, vegetables Food industry 2. Indirect values Indirect values involve the functions performed by biodiversity which are not of any direct use. It has many types like a) Social values b) Ethical values c) Aesthetic values d) Optional values e) Ecosystem service values f) Genetic value Fundamentals of Environmental Science 1.29 a) Social values Social values of the biodiversity refer to the manner in which the bio-resources are used to the society. Social value tends to vary from country to country as well as among cultures. These are values associated with the social, religion, spiritual aspects of life. Some plants and animals are considered holy. Holy plants: Tulsi, Lotus, Peepal, Neem etc Holy animals: Cow, Snake, Peacock Holy river: Ganga, Cauveri, Pamba b) Ethical values Biodiversity lies in the understanding that humans are part of nature and one among the other species. It involves ethical issues like “All life must be preserved”. Other animals must be allowed to live on earth irrespective of whether a species may or may not be useful. The very existence of different species in nature gives pleasure. c) Aesthetic values The beauty of the nature has aesthetic values. Most important aesthetic value of biodiversity is eco-tourism. Eco-tourism facilitates the enjoyment of nature. It also generates many forms of income and employment in the tourism sector. d) Optional values It is quite possible that many of the values of biodiversity are still unexplored. Optional values include the potentials of biodiversity that are presently unknown and need to be explored. These could be useful in future. It is quite possible that we may have potential cure for many diseases like cancer, ebola, AIDS in the depths of sea or in a tropical rain forest. e) Ecosystem service value Ecosystems serve all living things in variety of ways. These comes ecosystem service value. It includes, 1.30 Environmental Science  Air Purification: Trees helps purifying air by absorbing greenhouse gases. During photosynthesis, trees absorb CO2, releasing O2, thus purifying the air.  Protection of water: Trees regulates and stabilizes water flow. It helps to replenish water table and helps to increase water yield and quality. Example: coastal wet lands and mangroves.  Soil formatting and protection: Trees helps in the maintenance of soil quality. It also helps to prevent soil erosion.  Nutrient cycling: Cycling of nutrients in the ecosystem  Food production: Production of food for all life forms.  Climate control: Forest plays an important role in checking global warming and hence regulating the climate f) Genetic value Some ecosystems like rain forests are abundant in variety of flora and fauna. It can act as genetic reservoirs from which seed and other materials can be obtained. Biodiversity can be used as a “gene pool” for producing disease resistant, high yielding varieties. Greater the diversity among flora and fauna, greater is the diversity in “gene pool”. 1.10. CLASSIFICATION OF SPECIES Conservation status of a species indicates whether the species still exists and how likely the species is to disappear in the near future. Species are classified as follows. Extinct species: A species is said to be extinct when it is not seen in the wild for 50 years at a stretch. Example: Dodo, passenger pigeon, dinosaur, mammoth, saber-toothed tiger. Endangered species: A species is said to be endangered when the number has been reduced to a critical level or whose habitats have been drastically reduced. They can become extinct when not protected and conserved. Example: Giant panda, Indian elephant, Royal Bengal Tiger. Fundamentals of Environmental Science 1.31 Critically endangered species: These are species which face extremely high risk of extinction in immediate future. Example: Asiatic Cheetah Few endangered species of India Species Examples Reptiles Green sea turtle, Tortoise, Python Peacock, Great Indian Hornbill, Pelican, Birds Siberian, White Crane Indian wolf, red fox, royal Bengal tiger, Carnivorous mammals lion, red panda, leopard, striped hyena, desert cat Capped monkey, Golden monkey, Nilgiri Primates langur, Hoolock gibbon Plants Many species of orchids  Endemic species: Species which are restricted to a particular area is called as endemic species. Example: Nilgiri Tahr, Lion tailed macaque.  Endemic flora in India: Sapria himalayana, Uvaria lurida, Nepenthes Khasiana, Pedicularis perroter etc  Endemic fauna: Lion-tailed macque, Nilgiri leaf monkey, Brown palm civet, Nilgiri Tahr  Keystone Species: Species or set of species whose impact on its community or ecosystem is much larger and more influential are termed as keystone species. Extinction of keystone species may lead to the extinction of many other forms of life. Keystone species help to support the ecosystem (entire community of life) of which they are a part. In African savanna (grassland), elephants are the key stone species as they shape their environment. They destroy trees, making room for the grass species. Without elephants, much of the savannah would turn into woodland or forest. Beaver, starfish are other examples. 1.32 Environmental Science  Indicator Species: Species that serve as early warnings of damage to a community or ecosystem. They are very sensitive and quickly respond to environmental change and are considered as biological indicators. They give early indications that a habitat is suffering. Indicator species are first to react to external influences such as water pollution, air pollution, or climate change.  Example: Presence or absence of trout (a kind of fish) species in water indicates the quality of water. Stoneflies indicate high dissolved oxygen in water.  Native species: Species that are normally seen in a particular ecosystem and these species are native to particular area.  Exotic or alien Species: Species that migrate or accidentally introduced into an ecosystem by human beings. 1.11. HOT SPOTS OF BIODIVERSITY Hot spots are areas that are rich in endemic species and containing high diversity of species which are under threat. Key criteria for determining Hot Spots are: Presence of large number of endemic species the region should contain 0.5% of plant endemic species. Degree of threat which is measured in terms of habitat loss (70% loss) Around the world, at least 35 areas qualify under this definition. Of these four biodiversity hot spots are in India. Himalaya: Includes the entire Indian Himalayan region (and that falling in Pakistan, Tibet, Nepal, Bhutan, China and Myanmar) Indo-Burma: Includes entire North-eastern India, except Assam and Andaman group of Islands (and Myanmar, Thailand, Vietnam, Laos, Cambodia and southern China) Sundalands: Includes Nicobar group of Islands (and Indonesia, Malaysia, Singapore, Brunei, Philippines) Fundamentals of Environmental Science 1.33 Western Ghats and Sri Lanka: Includes entire Western Ghats (and Sri Lanka) Four hot spots of biodiversity in India 1. Himalayas Himalayas is the region comprising north eastern India, Nepal and Bhutan. These regions have very high mountain ranges, which include Mount Everest and K2, two biggest mountain peaks in the world. Plants and animals are found even in high altitudes. Biodiversity:  Plants: Of the estimated 10,000 species of plants in the Himalaya hotspot, about 3,160 are endemic. Many rare plant species are found even in the highest reaches of the Himalayan Mountains. Large numbers of rare orchids are found in this region.  Birds: Nearly 1000 birds are found in this region, but only 15 are endemic.  Mammals: Nearly a dozen mammals are found to be endemic. Endemic species include golden langur, the Himalayan tahr and Namadapha flying squirrel. 1.34 Environmental Science  Reptiles and amphibians: Of 175 reptiles recorded, only 50 are endemic. Among 105 amphibians known, more than 40 of which are endemic. 2. Indo-Burma The Indo-Burma hotspot comprises the Southeast Asian nations of Vietnam, Thailand, Cambodia, Laos, Myanmar (formerly, Burma), and portions of eastern India and southern China. Of the 13,500 vascular species found in Indo-Burma, 52 percent are endemic to the region. Biodiversity:  Plants: There are more than 300 globally threatened plant species in Indo- Burma, comprising two-fifths of the hotspot’s globally threatened species.  Birds: Bird life in Indo-Burma is also incredibly diverse, holding almost 1,300 different bird species, including the threatened white-eared night-heron, the grey-crowned crocias, and the orange-necked but only 15 are endemic.  Mammals: At least a quarter of Indo-Burma's mammal species are considered globally threatened. Of which 20 are endemic. Critically Endangered Delacour’s leaf monkey and pygmy loris are among them.  Reptiles: Two dozen species are known as endemic species of reptiles. Critically Endangered Siamese crocodile is richest non-marine turtle fauna in the world. 3. Sundalands Sundaland has a high level of biological diversity which can be attributed to its unique geology and geography. It is located between the Pacific and Indian Oceans, and bridges the continents of Australia and Asia. Biodiversity:  Plants: Approximately 60% of the 25,000 species of vascular plants found in Sundaland are endemic. The islands host more than 2,000 species of orchids  Birds: Of the approximately 770 bird species that regularly occur in Sundaland, nearly 150 are endemic. One of the endangered species is Javan hawk-eagle Fundamentals of Environmental Science 1.35  Mammals: Of Sundaland's more than 380 mammal species, more 170 are endemic to the hotspot.  Reptiles: There are more than 450 species of reptiles, roughly 250 of which are endemic. 4. The Western Ghats and Sri Lanka Western Ghats is a long mountain range running through the west coast of India. It covers the states of Kerala, Tamil Nadu, Karnataka, Goa, Maharastra and Gujarat extending upto 1600 kms length. Western Ghats is considered as one of the top ten global biodiversity hot-spots. Due to their proximity to the ocean they receive high rainfall. These regions have moist deciduous forest and rain forest. The region shows high species diversity as well as high levels of endemism. The vegetation in this hotspot originally extended over two lakh square kms. Currently, its been reduced to just 43,000 sq. km. Biodiversity:  Plants: Western Ghats covers about five percent of India's land but nearly 30% of plant species (4,000 of 15,000 species) are found here. Nearly 1,800 of these are endemic to the region. Major part of the world's spices such as black pepper and cardamom are found in the Western Ghats.  Birds: The Western Ghats has over 450 species of birds (35% endemic).  Mammals: The Western Ghats has over 140 species of mammals (around 20% endemic).  Reptiles: The Western Ghats has over 260 species of reptiles (over 60% endemic). RED LIST OF THREATENED SPECIES (RED DATA BOOK) Red Data Book is a state document established for documenting rare and endangered and threatened species of animals and plants. International Union for Conservation of Nature and Natural Resources (IUCN) publishes list..3 1.36 Environmental Science The main objectives are Identification and docu mentation of endangered species Create awareness about the importance of threatened biodiversity Defining conservation priorities and guiding conservation action Species are classified by the IUCN Red List into nine groups according to rate of decline, population size, area of geographic distribution etc.  Extinct (EX): No known individuals remaining.  Extinct in the wild (EW): Known only to survive in captivity like zoo etc. No animals found free in wild.  Critically endangered (CR): Extremely high risk of extinction in the wild.  Endangered (EN): High risk of extinction in the wild.  Vulnerable (VU): High risk of endangerment in the wild.  Near threatened (NT): Likely to become endangered in the near future.  Least concern (LC): Lowest or no risk.  Data deficient (DD): Not enough data to make an assessment of its risk of extinction.  Not evaluated (NE): Has not yet been evaluated against the criteria. 1.12. THREATS TO BIODIVERSITY Due to rapid increase in human population, the demand for food, shelter, energy, raw materials also increased. Deforestation resulted in the in extinction of species. It is estimated that every year nearly 10000 species becomes extinct. Extinction of species results in the loss of biodiversity. Fundamentals of Environmental Science 1.37 Factors leading to loss of biodiversity 1. Destruction of Habitats: Destruction and loss of natural habitat is the major reason for biodiversity loss. Due to deforestation animals are deprived of shelter and food. 2. Habitat Fragmentation: Sometimes the loss of habitat occurs slowly in instalments as it is divided into small and scattered patches. This is known as habitat fragmentation. Some wild animals like bears and large cats need large territories to live and fluorish. Habitat fragmentation affects their population as they breed only in the interiors of the forests. 3. Disturbance and pollution: Manmade activities such as air/water pollution, eutrophication etc affects biodiversity adversely. Increase in acidity of water bodies due to acid rain may result in the death of fishes and other aquatic organisms. Forest fire can result in habitat destruction and death of animals. Soil pollution due to the use of pesticides kills bacteria and insects. 4. Introduction of exotic species: Exotic species are new species entering a geographical region. They alter the habitat and natives cannot survive. Exotic species may kill or eat native species to the point of extinction. Disease causing microorganism if introduced may cause epidemic and eliminate the native species completely. Example: Water hyacinth is exotic species which was introduced from South America. Excessive growth of this resulted in clogging of rivers and lakes. It even threatens the survival of fishes and many aquatic species in India. 5. Hunting and over exploitation: Man hunts wild animals for food, safety and pleasure which can result in extinction of species. Example: Disappearance of dodo. Over fishing is depleting marine and fresh water living resources. Many species of fishes, sea turtles, sea cows and whales are facing extinction. 6. Poaching: Killing of wild animals for illegal trading of wildlife products is called poaching. Despite international ban, products from endangered species, smuggling 1.38 Environmental Science of wildlife items like furs, horns, tusks and herbal products are still going on. Animal products of commercial value include, ivory, horn, teeth and bone. 7. Man wildlife Conflicts: Sometimes wild animals like elephant, lion and tiger may come out from their natural habitat and cause damage to life and property of humans. Conflicts between man and wild animals are called man-wildlife conflict. It is estimated that every year in our country around 300 people die due to animal attack. These attacks are common in places where human settlement is closer to forest areas. Reasons for man-wild life conflict Habitat loss: Loss of habitat forces the animal to move out of forests Human encroachment: Humans occupy animal habitat, leaving animals want of space. Disease: Weak and sick animals attack humans for self-protection. Shortage of food and water during summer: Severe summer may result in shortage of water and food. So animals enter human settlements in search of food and water. Electric fencing: Very often farmers put electric fencing around farm lands. Elephants and other animals may get injured, suffer in pain and turn violent. Protection: Females of many animal’s attack to secure their babies. Remedial measures to curb man-animal conflict Ensure that adequate food and water is available for wild animals within the forest zones. Developmental and constructional work in and around forest region must be stopped. More space should be provided for protected area (National parks, bio reserves etc). Fundamentals of Environmental Science 1.39 Case study: Man-animal conflicts Wayanad, district in Kerala share its border with both Karnataka and Tamil Nadu. It has Bandipur National Park and Mudumalai National park as its borders. In 2016, Wayanad in Kerala saw over 70% less rainfall. This result in animals like elephants, bisons, monkeys, leopards etc made regular visits to villages adjacent to forest in search of food. Devoid of food and water made elephant herds aggressive and wild and wide destruction of agricultural crops. 1.13. CONSERVATION OF BIODIVERSITY Biodiversity has so many uses (genetic, commercial, cultural, medical and aesthetic) associated with it, hence it is worth protecting. Conservation of biodiversity refers to the protection, preservation, management, or restoration of plants and animals. Conservation of biodiversity can be achieved in two ways. In situ conservation Ex situ conservation In situ Conservation: In situ conservation refers to the conservation of plants and animals in their own natural habitat where they survive. Example: Biosphere reserve, National parks, Wildlife Sanctuaries etc. The aim of in situ conservation is to maintain biodiversity within the natural habitat where it is found. Plants are allowed to grow and develop as a part of their natural habitat. 1. National Parks A national park is an area dedicated for the conservation of wildlife along with its environment. It is also meant for enjoyment of tourism without harming environment. Activities such as cultivation, grazing, cutting etc are not allowed. Private ownership right and manipulation of habitat not allowed. Each national park aims to conserve one or more special species along with others. In 2024, India has 106 national parks. In addition to the above, 75 other National 1.40 Environmental Science Parks are proposed. India's first national park was established in 1936, now known as Jim Corbett National Park, Uttarakhand. Some Important National Parks in India National park Animal preserved Bandipur National Park, Karnataka Tiger Gir Forest National Park, Gujarat Lion Jim Corbett National Park, Bengal Tiger Uttarakhand Mudumalai National park Tamilnadu Elephant, Bengal Tiger Kaziranga National Park, Assam One horned Rhino Periyar National park Elephant, Bengal Tiger National parks in India Fundamentals of Environmental Science 1.41 2. Wildlife Sanctuaries Wildlife sanctuaries are also protected areas where killing, hunting, shooting or capturing of wildlife is prohibited. However, private ownership rights are permissible. Here, forestry operations are also permitted to a limited extent as long as it doesn’t affect the wildlife adversely. As of November 2023, India has established 573 wildlife sanctuaries. Wildlife Sanctuaries in India 1.42 Environmental Science Some Important Wild life Sanctuaries in India Wild life Sanctuaries Animal preserved Vedanthangal Bird Sanctuary, TamilNadu Water birds Pulicat Lake Bird Sanctuary, Tamilnadu Water birds Indian wild ass Sanctuary, Gujarat Indian wild ass Cauvery Wildlife Sanctuary, Karnataka Elephant, Spotted deer etc Ranganthittu Bird Sanctuary, Karnataka Water birds Sathyamangalam Wildlife Sanctuary and Elephant, Tiger Tiger Reserve, Tamilnadu Difference between Wild Life Sanctuary and National Park Aspect Wildlife Sanctuary National Park Definition A protected area for the A protected area aimed at conservation of wildlife preserving flora, fauna, and and their habitat. overall biodiversity. Human Limited human activities Strictly regulated with no Activities such as grazing and human interference allowed, controlled tourism may be except for tourism in allowed. designated areas. Degree of Less stringent compared High level of protection with Protection to national parks. stricter laws and regulations. Fundamentals of Environmental Science 1.43 Aspect Wildlife Sanctuary National Park Legal Status Governed by the Wildlife Also governed by the Wildlife Protection Act, 1972 Protection Act, 1972, with more (India). restrictive provisions. Boundaries Not always fixed or Clearly defined and legally notified demarcated. boundaries. Ownership Can be privately or Always under the control of the government-owned. government. Focus Focus on protecting Emphasis on conserving specific species or ecosystems and biodiversity as a habitats. whole. Tourism Tourism is regulated but Tourism is highly controlled and may be less restricted. limited to specific zones. Examples Periyar Wildlife Kaziranga National Park (Assam) Sanctuary (Kerala) Biosphere reseve A special category of protected areas where in people are an integrated part of the environment for long-term conservation. Area is much larger when compared to national park and wildlife sanctuary. Protection is granted for flora, fauna and to the human communities who inhabit these regions and their ways of life. Within biosphere we can have one or more national parks. There are 18 biosphere reserves in India. 1.44 Environmental Science Biosphere reserves in India Some Important biosphere reserves in India Name States Gulf of Mannar Biosphere Reserve Tamil Nadu Sundarbans Biosphere Reserve West Bengal Nanda Devi Biosphere Reserve Uttarakhand Nilgiri Biosphere Reserve Tamil Nadu, Kerala, Karnataka Fundamentals of Environmental Science 1.45 Roles of biosphere reserves Each biosphere reserve has three basic functions. Conservation of Biodiversity by conservation of ecosystems, species and genetic variation. Promoting Sustainable Development by assisting economic and human development which is socio-culturally and ecologically sustainable. Support for Logistics by supporting research, monitoring, education and information exchange. Advantages of in situ conservation It is cheap and convenient method. Species gets adjusted to the natural habitat and can lead a free “unmonitored” life. Disadvantages of in situ conservation Large area is required. Maintenance of habitat is not proper due to shortage of staff and pollution. Ex situ Conservation: Ex situ conservation include conservation of plant and animal species outside the habitat. The species are provided their habitat artificially. Threatened animals and plants are taken out from their natural habitat and placed in a place where they can be protected and given special care. Example: Gene banks, Botanical Gardens, Zoos, Genetic resource center. Methods of Ex-Situ Conservation Long Term Captive breeding Zoo’s and botanical Gardens are vital in preserving critically endangered species. Animals are bred in captivity. Special care and attention is given to their off springs produced. 1.46 Environmental Science Short Term propagation and release Rare species are bred in captivity and released into their natural habitat later. This will help to increase the number of animals in the wild. Example: Eggs of turtles are protected and helped to hatch. Young turtles are set into the sea. Cryo-preservation Seeds, pollen, gametes and embryos of endangered species are stored in liquid nitrogen at temperature as low as -196 C. Tissue culture Tissue culture is the growth of tissues or cells outside the organism. Cells or tissues are collected from a donor and transferred into a semi-solid, or solid growth medium, such as broth or agar. Tissues multiply to give large number of tissues. Tissue culture can be employed for the culture of both plant and animal cells. By artificial insemination Breeding of the captive species can be done by artifical insemination. In this method healthy semen is collected from a male animal and is then injected to a female for breeding. Cloning Cloning is the process used to create an exact genetic replica of another cell, tissue or organism. The copied material, which has the same genetic characteristics as the original, is referred to as a clone. The most famous clone was a Scottish sheep named Dolly. There are three different types of cloning: 1) Gene cloning, which creates copies of genes or segments of DNA. 2) Reproductive cloning, which creates copies of whole animals 3) Therapeutic cloning, which creates embryonic stem cells. Scientists use these cells to grow healthy tissue to replace injured or diseased tissues. Fundamentals of Environmental Science 1.47 Seed banks and Gene banks Seeds and genetic resources of different strains of commercially important plants can be stored for long periods in seed banks. Important Gene/Seed banks in India  National Bureau of Plant Genetic Resources (NBPGR), New Delhi: Agricultural and horticultural crops are preserved by cryo-preservation.  National Bureau of Animal Genetic Resources (NBAGR), Haryana Preserves the semen of domesticated bovine animals:  National Facility for Plant Tissue Culture Repository (NFPTCR), New Delhi: Conservation of varieties of crop/plants/trees by tissue. Advantages of ex situ conservation Survival of endangered species is increasing due to special care and attention. Some endangered species do not have any chance of survival if left free in nature. In captive breeding, animals are assured of food, water, shelter and security. Hence longer life span for animals. Disadvantages of ex situ conservation It is an expensive method. Freedom of wildlife is lost. Many captive animals struggle to survive when left free in natural environment. It can be adopted for only few species. 1.48 Environmental Science QUESTIONS PART-A 1. Explain the scope environmental science. 2. Define biodiversity. 3. What is food chain? 4. What is food web? 5. Distinguish between food chain and food web. 6. Define ecosystem diversity. 7. What are keystone species? Give example. 8. What is meant by endemic species? 9. Give a list endemic flora and fauna in India. 10. What do you mean by hotspots of biodiversity? 11. List the name of major national parks in India. 12. List the name of major wildlife sanctuaries in India. 13. What is meant by in-situ conservation of biodiversity? PART-B 1. Define ecosystem. Give an account of structure and function of an ecosystem. 2. Describe the function of an ecosystem using energy flow and material cycling. 3. With a neat sketch discuss nitrogen cycle 4. Explain the structure and functions of a forest ecosystem. 5. Explain the structure and functions of a pond ecosystem. 6. Briefly explain the energy flow in the ecosystem. 7. Explain the stages of ecological succession using appropriate terminology. 8. Explain the following (1) Ecological succession (2) Ecological pyramids. 9. What is biodiversity? Discuss the values and significance of biodiversity. 10. What do you mean by hotspots of biodiversity that extend in India? 11. What do you mean by conservation of biodiversity? State and explain basic approaches to wildlife conservation. Fundamentals of Environmental Science 1.49 12. Define and explain in-situ and ex-situ conservation of biodiversity. 13. What are the threats to biodiversity? Natural Resources 2.1 UNIT – II NATURAL RESOURCES Forest resources: deforestation– Water resources: over- utilization of surface water and, conflicts over water, dams-benefits and problems – Mineral resources: environmental effects of mining Food resources: fertilizer-pesticide problems– Energy resources: Need for renewable energy sources, use of alternate energy sources (Wind, Solar, Geothermal) – Land resources: soil erosion and desertification. 2.1. INTRODUCTION A natural resource may be defined as any material obtained from nature which can be used as such or transformed to do something more valuable and useful. They include the air to breathe, water to drink, land to live on, walk on and grow the food on etc. The natural resources are of two kinds: i) Renewable Resources: These resources are naturally regenerated within a given span of time. Most of them are continuous. However, some renewable resources may become non- renewable if over-exploited or not given enough time for regeneration. Example: Solar energy, forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc. ii) Non-renewable Resources: These are resources that have limited supply. They exhaust after certain time. Once we exhaust these reserves, the same cannot be replenished. Example: Fossil fuels like coal, petroleum, minerals etc. The important natural resources are: 2.2 Environmental Science  Forest resources  Water resources  Mineral resources  Food resources  Energy resources  Land resources 2.2. FOREST RESOURCES Forests are one of the most important natural resources on this earth. A forest is a natural ecosystem having diversified species of herbs, shrubs, small trees, large trees in different stages of lifespan. A variety of microorganisms, insects, reptiles, mammals, are seen in forests. Forest resource Uses or Functions of forests: Ecological functions:  Production of oxygen: During photosynthesis trees release oxygen which is so vital for all life forms. They are called earth’s lungs. More than 20 percent of the world oxygen is produced in the Amazon rainforest. Natural Resources 2.3  Reducing global warming: CO2 (a major greenhouse gas) is absorbed by the forests during photosynthesis. Thus, forest helps to keep earth cooler by absorbing green houses.  Regulation of hydrological cycle: Forests help to regulate water cycle by condensing water vapour in clouds resulting rains.  Prevention of soil erosion: Roots of the trees hold together the topsoil and prevent from directly washing soil away. It also prevents landslides and flash floods.  Improving soil fertility: Leave litter helps in maintaining soil fertility. It helps to maintain soil nutrients and structure.  Pollution moderators: Forests help to purifying air by absorbing many toxic gases from atmosphere. They also absorb noise, thus reducing noise pollution.  Regulation of heat: Forests play a crucial role in controlling heat by the absorption of solar heat during evaporation and transpiration.  Wildlife habitat: Millions of wild animals live in forests. Forests are home to millions of plant species too. It is estimated that about 7 million species are found in the tropical forests alone.  Reducing the rate of surface run-off of water: Trees retain the water with the help of roots and reduces surface run off. Productive functions  Supply of Raw Material: Forest is a source of raw material for various industries. Wood is a major raw material which is widely used as fuel, raw material for pulp, paper, furniture etc.  Commercial uses: Forests yields many commercial goods like timber, firewood, food items, gum, resins, fibres, lac (resinous substance), fodder, medicine, drugs etc. 2.4 Environmental Science Recreational, Developmental and Educational Functions  Eco tourism: Forests and dams can promote eco-tourism.  Employment functions: Forest directly and indirectly acts as a source for employment to a few people.  Revenue: Forest contributes to the economic development of the country because they provide goods and services to the people and industry. DEFORESTATION Removal of earth’s forest is known as deforestation. It is the cutting of trees, transforming a forest into cleared land. This can result in serious environmental problems. The world’s rain forests could completely vanish in a hundred years at the current rate of deforestation. Deforestation Causes Agriculture: Conversion of forests to agricultural land to feed growing numbers of people. Forests are cut down to plant cash crops like pepper, rubber etc. Fuel requirements: Growing population result in increased fuel demands. In rural areas, wood is still the major fuel. Trees are cut down for the demand of firewood. Natural Resources 2.5 Developmental projects: Constructing roads, railway tracks etc require clearing of forests on a large scale. Dams and reservoirs: Dams and Hydroelectric projects in forest area cause massive deforestation. Over 60,000 hectares of forest area was cleared for the construction of Narmada Dam. Several hectares of forest were submerged under water. Raw materials for industrial use: Wood are an important raw material for many purposes. For making furniture, boxes, plywood, pulp for paper trees are cut down. Mining: Surface and sub-surface mining for the extraction of mineral resources cause extensive deforestation. Digging a coal, diamond, or gold mine requires the removal of all forest cover. Forests are further cleared for the transport of trucks and other equipment. Forest fires and volcanic eruption: Forest fires and volcanic eruption can cause deforestation. Forest fire is common in tropical regions during summer. Overgrazing: Overgrazing by cattle’s cause deforestation. They not only destroy the vegetation but also pull out the roots of plants. Consequences Global warming: Increasing CO2 levels lead to rise in temperature of earth. Forests are known as earth’s lungs as they play a great role in regulating the amount of greenhouse gases like CO2. Soil erosion: Roots of trees helps to hold soil together preventing soil erosion. Removal of trees will lead to easy removal of topsoil by water, wind etc. Loss of habitat: Due to deforestation, forest animals and plants will lose their natural habitat. This may cause migration of animals or man-animal conflicts. Loss of soil fertility: Leaf litter is rich in organic matter which is converted into nutrients by microorganisms present in the soil. Absence of leaf litter can reduce soil fertility. 2.6 Environmental Science Change in rainfall pattern: Forests play an important role in regulation of hydrological cycle. Deforestation can cause decrease in rainfall or erratic rainfall pattern. Lowering of water table: Deforestation results in less rainfall which may result in lowering of water table. Shifting of tribal people: Large scale deforestation may result in shifting of tribal population to urban areas. Loss of biodiversity, genetic and species diversity: Deforestation will lead to the loss of biodiversity such as varieties of flora and fauna. Endangered plants and animals may become extinct. Loss of forest products: Many forest products like honey, medicinal plants etc will become costly. Desertification: Large scale deforestation may lead to forest becoming arid, semi-arid or desert. Steps to prevent deforestation or the role of individual in preserving forest resources:  Starting afforestation (tree planting) programs.  Educating people about the ill effects of deforestation through movies, documentaries, street play, newsletters etc.  Strict implementation of Forest Conservation Act  Implementing people’s participatory programmes on forest moment involving Joint Forestry Management (JFM) programme of India.  Avoids diversion of forest lands for other activities through acts like Forest Conservation Act and Wildlife (protection) Act  Control forest diseases and forest fire  Recycling or replacing forest products may result in less dependence of forest. Natural Resources 2.7 Deforestation- Case studies  The Amazon Rainforest, often called "the lungs of the Earth," faces massive deforestation due to cattle ranching, soybean farming, logging, infrastructure projects like the Trans-Amazonian Highway, and mining. This has caused biodiversity loss, including species like jaguars, and disrupted global climate patterns by reducing carbon absorption. Between 2001 and 2021, the Amazon lost 17% of its forest cover.  In India, the Western Ghats, a biodiversity hotspot, suffer from deforestation caused by plantations, urbanization, infrastructure projects, and mining. This has endangered species like the Lion-tailed Macaque, increased soil erosion, and caused frequent landslides and floods. Nearly 30% of its forest cover has been lost since the 1970s. Conservation efforts, such as eco-sensitive zones and reforestation programs, are underway but face challenges. Chipko movement: Chipko movement was the first forest conservation movement started in India in the early 1970’s. The word “chipko” in hindi means hugging or embracing. Earlier contractors used to make huge profit by timber extraction. Chipko movement ensured that contract system was abolished, and indiscriminate felling of trees stopped. Noted environmentalist and journalist, Sri Sundarlal Bahuguna was one of the pioneers of the movement. Chipko Movement 2.8 Environmental Science 2.3. WATER RESOURCES Earth is the only known planet to contain water, hence known as “blue planet”. All life of earth depends on water. About 97% of the earth’s surface is covered by water and most of the animals and plants have 60-65% water in their body. About 97% of the earth’s water supply is found in oceans. This is unfit for domestic purposes. 2% is locked in the polar icecaps which again in unusable. Thus only 1% is available as fresh water in rivers, lakes, streams, reservoirs, and ground water which is suitable for human consumption. Distribution of the world’s water Hydrological cycle The movement of water on the earth's surface and through the atmosphere is known as the hydrologic cycle or water cycle. Water vapour reaches the atmosphere from earth's surface form through evaporation, condenses and form clouds. Water then returns to the surface of the earth in liquid (rain) or solid (snow, sleet, etc.). Step 1: Evaporation and transpiration Water bodies like oceans, lakes and the river bodies absorb heat energy from the sun and turns into water vapour. Through evaporation, water moves from Natural Resources 2.9 hydrosphere to atmosphere. Transpiration is a process similar to evaporation where liquid water is turned into water vapour by the plants. It is the evaporation of water from leaves through stomata (very tiny openings on leaves) as water vapour. Step 2: Condensation Water vapour formed by evaporation; it rises in the atmosphere. At high altitudes, where the temperature is low, the water vapour changes into very tiny particles of ice /water droplets. This process is called condensation. These water particles come close together and form clouds and fogs in the sky. Step 3: Precipitation Due to wind or change in temperature, the water droplets in clouds combine to make bigger droplets and precipitates as rain. If the temperature is less than zero, the water droplets fall as snow. Step 4: Runoff and infiltration Water that pours down as rain leads to runoff. The process where water runs over the surface of earth is called Runoff water. During runoff, water carries topsoil and minerals along with the stream. This runoff combines to form small channels and then rivers and finally ends up into lakes, seas, and oceans. A part of rainwater does not runoff into the rivers but moves deep into the soil through different layers. This is called infiltration. This water which seeps down in earth increases the level of ground water table. Hydrological cycle 2.10 Environmental Science Types of freshwater resources Freshwater may be present either as surface water or as underground water. Freshwater resources Surface water: Surface water refer to water present on the surface of earth, either stagnant type or flowing type. Stagnant water bodies are called lentic and flowing water bodies are called lotic water. Examples: Lentic water: Lakes, Ponds etc Lotic water: Rivers, Streams etc. Underground water: Underground water means the water present under the earth’s surface. A layer of sediment or rock that is highly permeable and contains water is called an aquifer. Aquifers are of two types: I) Unconfined aquifers II) Confined aquifers Natural Resources 2.11 Unconfined aquifers receive water seeping down from above. It is constantly recharged. Upper boundary of an unconfined aquifer is water table. Confined aquifers are sandwiched between two impermeable layers of rock or sediments. It is recharged only in those areas where the aquifer intersects the land surface. Over exploitation of ground water Due to rapid population growth and industrial growth, the demand for water has increased rapidly. Indiscriminate and unscientific use of water resources has resulted in water scarcity and water pollution. Causes  Agriculture: The main reason for the over exploitation of ground water is agriculture. Extensive irrigation including for livestock requires lot of water.  Increase in population: Domestic and industrial needs of the growing population require water.  Inadequate rainfall/ Drought: To meet severe weather conditions ground water is over exploited. Consequences  Lowering of water table: Large number of tube wells built can result in lowering of water table.  Ground subsidence: When groundwater withdrawal is more than its recharge rate, the clay layers in the aquifer get compacted and settle. This result in the sinking of land called ground subsidence. This can result in damage of buildings, fracture in pipelines etc.  Water logging and salinity: Rapid removal of ground water can cause the intrusion of sea water which results in increase in salinity. When excessive irrigation is done with brackish water it raises the water table gradually leading to waterlogging and salinity problems. 2.12 Environmental Science  Water pollution/Chemical contamination: Re

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