Environmental Studies Notes PDF

ENVIRONMENTAL STUDIES BLOCK 1-Chapter 1 1: Introduction INTRODUCTION: Environment consists of surroundings of an organism which includes abiotic and biotic environment. Thus,, environment refers to...

ENVIRONMENTAL STUDIES BLOCK 1-Chapter 1 1: Introduction INTRODUCTION: Environment consists of surroundings of an organism which includes abiotic and biotic environment. Thus,, environment refers to “sum of all i.e. water, air and land, along with their inter-relationship relationship among themselves and also other living organisms”. The word environment is derived from French Word“environner” which means “Surrounding”. Thus, Environment can be defined as the combined interaction of physical ,chemical and biological conditions affecting an individual or community in the complex of soci social and cultural conditions. Ecology is a study of such inter relationships between organisms and their environment. inter-relationships Ecology is derived from the two Greek words “oikos” means “house” or “place to live” and words, Ecology is the “study of orgaisms at home, “logos” means “Study of/science of”. In simple words, in their native environment”.  Ecology was first introduced by Reiter in 1869.  Eugene P. Odum(1969), an America ecologist defines ecology as “the study of structure and functions of nature” and more technically as “Study of structure and functions of ecosystems”. BRANCHES OF ECOLOGY: Autecology & Synecology are two main branches of ecology ecology. Autecology is the study of individual organism or individual species. It is also known as population ecology. Example: Tree in forest. Synecology is the study of group of organisms of different species which are associated together as a unit in form of a community. Example: Forest ENVIRONMENTAL STUDIES: Environmental studies is a multidisciplinary academic field which systemat systematically studies human interaction with the environment. Definition: Study of functional intricacies of environment in relation to an organism can be called as Environmental Studies. 1 EVS Notes Compiled by Asst. Prof ANUSHA T SCOPE & IMPORTANCE OF ENVIRONMENTAL STUDIES: 1. Environmental awareness: The study creates awareness among the people to know about various renewable and nonrenewable resources of the region. 2. Environmental knowledge: It provides the knowledge about ecological systems and cause and effect relationships. 3. Bio diversity Richness: It provides necessary information about biodiversity richness and the potential dangers to the species of plants, animals and microorganisms in the environment. 4. Natural disasters: The study enables one to understand the causes and consequences due to natural and main induced disasters (flood, earthquake, landslide, cyclones etc.,) and pollutions and measures to minimize the effects. 5.Environmental Issues: It enables one to evaluate alternative responses to environmental issues before deciding an alternative course of action. 6. Legal framework: The study enables environmentally literate citizens (by knowing the environmental acts, rights, rules, legislations, etc.) to make appropriate judgments and decisions for the protection and improvement of the earth. 7. Problems faced by the environment: The study exposes the problems of over population, health, hygiene, etc. and the role of arts, science and technology in eliminating/ minimizing the evils from the society. 8. Skills and technologies The study tries to identify and develop appropriate and indigenous eco-friendly eco skills and technologies to various environmental issues. 9. Sustainable utilization of resources It teaches the citizens the need for sustainable utilization of resources as these thes resources are inherited from our ancestors to the younger generating without deteriorating their quality. 2 EVS Notes Compiled by Asst. Prof ANUSHA T 10. Theory into Practice: The study enables theoretical knowledge into practice and the multiple uses of environment. ELEMENTS OF ENVIRONMENT: Environment vironment consist of following 3 elements: They are- are 1. Physical elements of environment consists of space, land forms, water bodies, soil, rocks & minerals. 2. Biological elements of environment includes plants, animals, micro-organisms micro present in Biosphere. 3. Cultural elements of environment comprises of economic, social and political elements and are essentially features made by man. Multidisciplinary Nature of Environmental Studies Encompassing the elements of Physics, Chemistry, Medical Science, Agriculture, Geography, and Biology, Environmental Studies is a vast field of study. Not only restricted to environmental conservation and management of resources, but it also emphasizes understand understanding:  Types of pollution and their harmful effects on living organisms  Biodiversity,, its types, and causes of degradation  Deforestation restation and methods to increase forest cover  Desertification  Waste disposal and sewage treatment, etc Environmental studies are made up of several components. It is multi disciplinary in nature.It includes subjects such as :  Anthropology:: It is the study of human traits, biological and psychological well-being, well communities and cultures, and the growth and evolution of humans. EVS is connected to anthropology since it studies humans and their environments throughout place and time.  Biology:: It is a field of science that focuses on the study of living creatures. Their physical structure, chemical processes, molecular interactions, development, and evolution are all biology since it is concerned with the natural environment included. EVS is connected to biology of living creatures.  Chemistry:: It is a field of science that examines chemicals and the components that make up matter. Understanding natural occurrences in EVS necessitates knowledge of chemistry.  Computers:: As the world has progressed, computers have become a need for everyone. Protection Agency to keep track of pollutants Computers are used by the Environmental Protection found in soil and water. 3 EVS Notes Compiled by Asst. Prof ANUSHA T   Geology:: It is the study of physical structures and substances found on Earth, as well as their history and the processes that they go through. EVS is also concerned with the study of the earth and the environment.  Economics:: It is a field of study concerned with the production, consumption, and distribution of commodities and services. Various economic strategies have been established to protect the environment from pollution, global warming, and a climate change by evaluating and developing answers or cures for environmental concerns.  Physics:: It is a field of science that examines energy and matter in space and time, as well eractions. Physics is concerned with energy conservation, atmospheric as their interactions. modelling, and many environmental concerns.  Sociology:: It is the study of social life, change, social causes, and the social socia repercussions of human action. It also addresses the connection between contemporary society and the environment.  Statistics:: It is the study of quantitative data collection, analysis, interpretation, and presentation. It is also used to evaluate data in order to find trends and recommend the optimal environmental growth. Sustainability and Sustainable Development: Development co exist on Earth over a long time. Definitions of this Sustainability is a social goal for people to co-exist term are disputed and have varied with literature, context, and time. Sustainability usually has three dimensions: environmental, economic, and social. Sustainable Development Satisfying the needs of the present population without endangering the capability of future population to satisfy its own needs. Sustainable development has been defined in many ways, but the most frequently quoted Our Common Future, also known as the Brundtland Report: "Sustainable definition is from -Our development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs."  Development that meets the needs of the present generation without compromising the ability of the future generation to meet their own needs.  redistributing resources and is hence a moral issue. Meeting the needs of all requires redistributing Edward Barbier defined sustainable development as ,”one ,”one which is directly concerned with increasing the material standard of living of the poor at the grass root level”. According to Herman Daly, a leading en vironmental economist, to achieve sustainable environmental development, the following needs to be done  limiting the human population to a level within the carrying capacity of the environment  technological progress should be input efficient and not input consuming 4 EVS Notes Compiled by Asst. Prof ANUSHA T   renewable wable resources should be extracted on a sustainable basis, that is, the rate of extraction should not exceed the rate of regeneration  renewable resources rate of depletion should not exceed the rate of creation of for non-renewable renewable substitutes  inefficiencies ies arising from fro pollution should be corrected. Three core elements of sustainable development are economic growth, social inclusion and environmental protection. It is crucial to harmonize them. ************* 5 EVS Notes Compiled by Asst. Prof ANUSHA T BLOCK 1-Chapter 2 ECOSYSTEMS 2-ECOSYSTEMS CONCEPT, STRUCTURE AND FUNCTIONS: The Ecosystem / Ecological system, is the “Functional unit” of ecology. Ecosystem may be defined as “any natural unit that includes a community of organisms and their complex environmental factors, interacting to produce a stable system. Eg: Ecosystem includes lake, pond, estuary forest etc. Lindeman (1942) defined ecosystem as “ a system composed of physical physical-chemical-biological processes active within a space-time space unit of any magnitude. CLASSIFICATION OF ECOSYSTEM STEM(Structure&Functions) Ecosystem Natural Artificial Terrestrial Aquatic 1. Gardens 2. Aquarium 3. Plantations Forest Grass land Salt water Fresh water Lentic ( Ponds Desert Marine & lake) Lotic (Rivers Estuarine & streams) NATURAL ECOSYSTEM: Ecosystem as occurring in nature are natural ecosystems. Natural ecosystems are classified into 1. Terrestrial or land based ecosystem 2. Aquatic or water based ecosystem 1. Terrestrial or land based ecosystem: Land based ecosystems are known as terrestrial ecosystems. a. Forest Ecosystem 6 EVS Notes Compiled by Asst. Prof ANUSHA T  A forest ecosystem is a natural woodland unit consisting of all plants, animals, and micro- micro organisms (Biotic components) in that area functioning together with all of the non-living non physical (abiotic) factors of the environment. b. Grass Land Ecosystem Grassland Ecosystem is an area where the vegetation is dominated by grasses and other herbaceous (non-woody) woody) plants. It is also called transitional landscape because grassland ecosystemss are dominated by the grass with few or no trees in the area where there is not enough for a forest and too much of a forest. forest.. c. Desert Ecosystem: Desert ecosystem is the driest ecosystem of the earth and this is the reason it has less vegetation and less diversity of life. It is one of the parts of the terrestrial ecosystem. The plants and animals of the desert ecosystem have mastered the art of survival in harsh conditions. A desert ecosystem is basically devoid of any rainfall or precipitation. 2. Aquatic orr water based ecosystem: Water based ecosystems are called aquatic ecosystem. a. The salt water ecosystem b. The fresh water ecosystem a. The salt water ecosystem: Salt ecosystem includes the marine and estuarine habitats i. Marine: Marine ecosystems are aquatic environments with high levels of dissolved salt, such as those found in or near the ocean ii. Estuarine: Estuarine Ecosystemare areas where both ocean and land contribute to a unique ecosystem. b. The fresh water ecosystem: Water on land which is continuously cycling and has low salt content is known as fresh water. Fresh water ecosystem is divided into 2 groups based on the nature of fresh water – Lentic & Lotic. i. Lentic: In lentic fresh water system, the water is standing still or static. s Eg: Pond & lake. system the water is running in nature i.e it is in ii. Lotic: In lotic fresh water system, continuous. Eg: Rivers & streams. ARTIFICIAL ECOSYSTEM: Ecosystems constructed by human beings like gardens, plantations or aquariums are called artificial or agro ecosystems. 7 EVS Notes Compiled by Asst. Prof ANUSHA T ECOSYSTEM – STRUCTURE & FUNCTIONS: Structure of an Ecosystem(Land (Land/forest Eco System) In an Ecosystem there are two major interacting structural components a) Abiotic Component b) Biotic Component a) Abiotic Component:ItIt comprises of non-living component of the environment. Light, soil, air and water are the abiotic components. b) Biotic Component: It consists of living components of the environment. Microscopic and macroscopic plants & animals form the biotic components of of an ecosystem. These are grouped into 2 categories - Autotrophs & Heterotrophs. Biotic Components Autotrophs Heterotrophs (Producers) (Consumers) Micro Macro Consumer or Consumers Decomposer Primary Secondary Consumer Consumer Tertiary Consumer Autotrophs (Producers): Autotrophs are organisms that are capable of producing the food using the green pigment chlorophyll from sunlight, carbon dioxide and water. Since fo food is produced by autotrophs, they are called as the producers. The energy needed for the existence of ecosystem autotrophs.Eg: Large trees, grasses, rooted and floating plants, the is produced by the autotrophs. microscopic algae and diatoms. Heterotrophs: Heterotrophshs are organisms who are unable to produce the food as they do not have the chlorophyll. For survival they are dependent on the autotrophs directly or indirectly. Hence, the heterotrophs are known as the consumers. The consumers are of 2 types: (a) Macro Consumers or phagotrophs and (b) Micro Consumers/ decomposers or Osmotrophs. 8 EVS Notes Compiled by Asst. Prof ANUSHA T  (a) Macro Consumers or phagotrophs: They are large sized consumers with a digestive system capable of digesting larger food molecules into smaller food molecules. The macro consumers are a further grouped into 3 types: 1. Primary consumers: A primary consumer is directly dependent on the producer for food. These are also known as herbivores. Eg: Cow, deer & rabbit etc. 2. Secondary consumers: These are the organisms that feed on primary consumer. A secondary consumer is also called as primary carnivores. Eg: Lion, cat , dog etc. 3. Tertiary consumers: These are the organisms, that obtain their food by feeding on either consume They are called as omnivores. primary or secondary consumers. omnivores Eg: Human, pigs & sparrow. (b) Micro Consumers/ decomposers or Osmotrophs: These are microscopic bacteria and fungi.They compose excreta of animals and dead parts of plants and dead bodies of animals.They are also called detrivores- dirt eaters.They are also referred to as the natural scavengers of the ecosystem. FUNCTION OF AN ECOSYSTEM: COSYSTEM: Functioning of an ecosystem is studies with reference to 2 aspects. They are; 1. The flow of energy is various directions, from and to within the living organisms, at different trophic levels. which, materials such as carbon, 2. A cyclical passage known as biogeochemical cycle in which, nitrogen, oxygen, sulphur, phosphorus and water circulate between the living and the non-living living components of ecosystem. THE FLOW OF ENERGY: The main sources of energy for an ecosystem is the light energy derived from the sun ((radiation energy). The passage of energy is an ecosystem comprises of following 6 processes. They are: 1. The autotrophs (green plants) covert the radiant energy of the sun into chemical energy by photosynthesis and energy is stored in the bonds of the sugar molecules. 2. A part of this chemical energy is used for metabolic activities like growth, reproduction etc. During this process, some amount of energy is lost as heat. 3. The autotrophs become the food and energy source for the herbivores/ primary consumers forr their metabolic activities. Energy is again lost as heat in the form of compounds such as urea & uric acid, which still contain usable energy. 4. The carnivores (Secondary consumers) consume herbivores and use them as source of energy with same end result as a in (3). 9 EVS Notes Compiled by Asst. Prof ANUSHA T  5. The tertiary consumers consume/eat secondary consumers for the same purpose and with the same result as in (3). 6. Decomposers degrade dead bodies of plants and animals and also the waste products of and it consists of several steps. The end animals. This process is called decomposition and products of decomposition are without energy. These are returned to the abiotic environment and are again used by plants as nutrients. As a result of the above 6 processes, the energy passes continuously is an ecosys ecosystem and matter is recycled again and again. TROPHIC LEVEL: The flow of energy at successive stages in an ecosystem is known as “Tropic level”. In ecology, “trophic” relates to “feeding and nutrition”. It is derived from the greek words trophe and trephein meaning food and to feed respectively. Tropic level comprises of a group of organisms in an ecosystem which obtain their food in the same general way. i.e, all the animals that obtain their energy from eating grass such as cattle, grasshoppers etc are part of the same trophic level. Aggregation or grouping of different trophic levels within an ecosystem is known as “Trophic structure” of an ecosystem. 1. Typically, an ecosystem has 3 to 4 trophic levels through which energy flows. In other words, theree are usually 3 to 5 groups of organisms which derive their nutrition is the P occupy the first trophic level – T1. same general way i.e, 1. the autotrophs /producers –P 2. The herbivores are the heterotrophs. These are the primary consumer – C1 , that obtain their energy directly from the autotrophs, and occupy the second trophic level – T2. 3. The carnivores (meat eaters) or secondary consumers – C2 that obtain their energy indirectly, from the autotrophs, occupy the third trophic level – T3. 4. The Tertiary consumers ers occupy the trophic level four-T4. four 10 EVS Notes Compiled by Asst. Prof ANUSHA T FOOD CHAIN: The trophic structure of an ecosystem is the basis of the food chain. Food chain is a system comparable to a chain with series of links in it. Thus, food chain is the sequence of organisms in which one organism feeds on that preceding it. Grass Grass Hopper Frog Eagle Explanation: 1) Producers (grass) is always the first link in a food chain. These produce the food by using sunlight. 2) Herbivores (grass hopper) that feeds on plant or plant parts is the second link in the food chain. 3) The third link in the food chain is the secondary consumers or a carnivore (frog). 4)The fourth link in the food chain is The tertiary consumers which is also a carnivore. Basically, food chain is of two types they are; a) Grazing food chain (GFC) b) Detritus food chain (DFC) Grazing food chain (GFC) The grazing food chain begins with green plants, (producers) goes to grazing herbivores (primary consumers) and to carnivores (secondary or tertiary consumers) Here, the energy is transferred from green plants to primary and secondary consumers. 11 EVS Notes Compiled by Asst. Prof ANUSHA T  Goat (Primary Lion (Secondary Grass (Producers) Consumers) Consumers) Detritus food chain (DFC) The detritus food chain begins with decaying organic matter of plant and animal bodies called as detritus. The food energy is transferred from detritus to detrivores (Earthworms, Millipedes etc) Detrivores, in turn are fed upon by larger organisms building up a food chain. Earthworms Detritus Frogs (Secondary Snake (Tertiary (Primary (Producers) Consumer) Consumer) Consumers) Food web: A food web is multiple feeding interactions between each species. A food web consists of all the food chains in a single ecosystem. Each living thing in an ecosystem is part of multiple food chains. chains. Each food chain is one possible path that energy and nutrients may take as they move through the ecosystem. There are unique interactions and relationships which are involved in the transportation distributed throughout the various of energy. The energy, once produced and captured, is distributed living organisms. This transfer of energy is termed as the food web. POND ECOSYSTEM/Aquatic /Aquatic Ecosystem Ecosystem: Pond ecosystem is an example for aquatic ecosystem. Aquatic Salt water Fresh water Lentic (Ponds & Lotic (Rivers & Marine Estuarine lake) Stream) Aquatic or water based ecosystem: Water based ecosystems are called aquatic ecosystem. a. The salt water ecosystem 12 EVS Notes Compiled by Asst. Prof ANUSHA T b. The fresh water ecosystem The salt water ecosystem: Salt ecosystem includes the marine and estuarine habitats. i. Marine: Marine ecosystems are aquatic environments with high levels of dissolved salt, salt such as those found in or near the ocean ii. Estuarine: Estuarine Ecosystemare areas where both ocean and land contribute to a unique ecosystem. The fresh water ecosystem: Water on land which is continuously cycling and has low salt content h water. Fresh water ecosystem is divided into 2 groups based on the nature of is known as fresh fresh water – Lentic & Lotic. i. Lentic: In lentic fresh water system, the water is standing still or static. Eg: Pond & lake. system the water is running in nature i.e it is in ii. Lotic: In lotic fresh water system, continuous. Eg: Rivers & streams. ECOSYSTEM(Aquatic Ecosystem) STRUCTURAL AND FUNCTIONAL COMPONENTS OF POND ECOSYSTEM(Aquatic Pond Ecosystem Abiotic Biotic Components Components Consumers Producers (Macro (Autotrophs) Consumers) Primary Secondary Phytoplankton Consumers Consumers Macroscopic Tertiary Plants Consumers Decomposers (Micro Consumers) 13 EVS Notes Compiled by Asst. Prof ANUSHA T Abiotic Components: It is also known as the non--living living components. The abiotic components of pond ecosystem include: 1. Light: Sunlight is the most important abiotic component. It provides the energy needed for the photosynthesis leading to the production of food by the producers. 2. Water: Water forms the habitat of the organisms. Water also contains dissolves disso salts of calcium, potassium, sodium etc. Dissolved gases like oxygen, carbon dioxide, nitrogen etc. are also present in water. Biotic Components: It is known as the living components of the ecosystem. They are grouped into 2 categories: 1. Autotrophs & 2. Heterotrophs Autotrophs: Autotrophs are also known as the producers of the ecosystem. They use sunlight, water, carbon dioxide and green pigment chlorophyll to produce the food. Autotrophs forms the first trophic types of autotrophs present in pond ecosystem. level of the ecosystem. There are 2 types 1. Phytoplankton: Minute floating plants such as algae and diatoms present throughout the area of pond are called Phytoplankton. Example: Blue-green green algae, green algae, diatom etc. 2. Macroscopic plants: These are large water plants also known as hydrophytes. large It consists of emergent vegetation (plants rooted in the shallow regions of the bank. Leaves emerge out of water), Submerged vegetation (Plants completely submerged under water) & floating vegetation. Example:Saggitaria, gitaria, Hydrilla, pistia, Vallisneria etc. Heterotrophs: Heterotrophs are the animals that cannot produce their own food. They are dependent on producers for the food energy. They are 2 types: a. Consumers b. Decomposers a. Consumers: Consumers are relatively large sized with a digestive system. 14 EVS Notes Compiled by Asst. Prof ANUSHA T These are further grouped into following types: 1. Primary Consumers 2. Secondary Consumers 3. Tertiary Consumers Primary Consumers: These depend directly on producers for food. Primary consumers form the trophic level II. Primary consumers are of following types: air water interface are called Neuston. It 1. Neuston:: Unattached organisms that live at the air-water contains floating plants like duckweed and animals such as water waterstiders. Insects tadpole etc. also are other examples of neuston. such as diving bettels, larvae, tadpole 2. Zooplankton: The animals that drift on water surface controlled by the water current are called Zooplankton. Eg: Cyclops, Daphnia etc. 3. Nekton: These are the aquatic swimming animals. They can swim independent of wave and water current as they posseslocomotary organs. Eg: Insect larvae, insects etc. 4. Benthos: These are the organisms living at the bottom of the pond. They are either found water sediment. Eg: Crustaceans living in the sediment or found at the interface of water- ,molluscs etc. Secondary Consumers: These are the organisms that feed on the primary consumer. Secondary consumers form the trophic level III. It is also called as a primary carnivore. Eg: Water Scorpion, water bug, fishes etc. Tertiary consumers: The animals that feed on the secondary consumers are called tertiary consumers. They form trophic level IV. Eg: Catfish water snakes etc. b) Decomposersor Micro consumers: These form the trophic level V of the pond ecosystem. It consists of aquatic bacterbacteria and fungi. They decompose the dead bodies and excreta of the consumers. This helps in recycling of minerals in the pond ecosystem. This recycling is essential for the stability of the ecosystem. 15 EVS Notes Compiled by Asst. Prof ANUSHA T FUNCTIONAL ASPECT OF POND ECOSYSTEM: Producers by photosynthesis nthesis synthesise food. This energy present in the producers is passed on sequentially from primary, secondary to tertiary consumers. Decomposers are responsible for the recycling of the minerals in the ecosystem. Thus all the different components of the ecosystem interact and influence one another. CONCEPT OF ECOLOGICAL SUCCESSION: Groups of plans and animals living together in a place can be called a community. The biotic communities are dynamic in nature and change with the passage of time. For example, a vegetation of small bushy plants may change into a thick forest of large trees over a period of time. The successive replacement of communities in an area over a period of time is known as ecological succession. succession Both abiotic and biotic comp onents are involved in such change. During succession, changes components occur both in plant and animal communities. The plant succession, however, is easily visible. Two basic types of succession can be distinguished. Primary Succession:: Succession occurring in barren areas where no vegetation or plants were present earlier (previously unoccupied sites) is called primary succession. Ex. Growth of plants on a barren rocky surface. Secondary Succession:: This refers to formation of new vegetation in an area which has h become barren due to removal or destruction of earlier natural vegetation. For example, an area where forest has been destroyed by fire or large scale felling of trees. General process of succession: The plants that invade the barren land initially, are ar called pioneer species. The assemblage of pioneer species forms the pioneer community. Generally, the pioneer ecies show high rate of growth. IItt short life span. In time, the pioneer community is replaced by species combination. This second community is replaced by a another community with different species combination. third community, and so on. The different communities or stages represented by combinations of mosses, herbs, shrubs and trees replacing one another during succession are referred to as seral stages or seral sera communities. The plant species which get established later, during the course of succession, are known as late successional species. These species are slow growing and long lived. The terminal stage of succession is represented by the climax community. The climax community is stable or permanent and does not show changes environment- conditions remain the same. The succession in species composition, as long as the environment occurring in water bodies like ponds and lakes called hydrarch succession, and the successi succession 16 EVS Notes Compiled by Asst. Prof ANUSHA T taking place in dry terrestrial areas with low moisture (for example, rock, sand) is known as xerarch. Succession in an aquatic habitat (Hydrarch): Ecological succession occurs in water bodies like ponds and lakes Water bodies are prone to silting as a result of soil erosion from surrounding areas. In a pond, the microscopic algae called phytoplanktons and zooplanktons constitute the pioneer community. Submerged aquatic plants with their roots anchored in the mud are next to colonise the pond. The dead remains of these organisms settle at the pond bottom. Besides, floating plant species invade the pond. With the continued siltation, the pond bottom is gradually raised and water layer becomes shallow and become rich in nutrients. ergent plants with aerial leaves, such reeds, are able to colonise the pond. As a result, rooted, emergent This is accompanied by the invasion of dragon flies, crustaceans and more rooted species of plants. Thus the species composition of the pond keeps changing with time. Pond becomes shallower until it gets transformed into a terrestrial habitat. Ultimately, terrestrial species, like grasses, bushes and trees, colonise the pond area and a climax community is established. The colonisation by land plants usually progresses from margins toward the center of the pond area. With increased settling of silt and deposition of dead organic matter derived from floating and rooted species, the pond area is ultimately converted in to a forest. ************* 17 EVS Notes Compiled by Asst. Prof ANUSHA T BLOCK 1-Chapter 3-NATURAL NATURAL RESOURCES AND MANAGEMENT The word 'Resource' means 'a source of supply' or support generally held in reserve. Living and living factors of nature used by humans for various purposes are called 'natural resources'. non-living These are used to support human life and fulfil human requirements. TYPES OF NATURAL RESOURCES On the basis of origin, natural resources may be divided into twotypes. They are; 1) Biotic resources 2) Abiotic resources 1. BIOTIC RESOURCES: organic materials, then they are considered biotic If natural resources come from living things or organic resources. Biotic resources include plants, animals, and fossil fuels. The three fossil fuels are coal, oil, and natural gas. Fossil fuels are classified as biotic resources because they were formed from the decay ecay of organic matter over millions of years. 2. ABIOTIC RESOURCES: non living and inorganic materials. For example, land, air, Abiotic resources originate from non-living sunlight, and water are abiotic natural resources. Minerals (gold, copper, iron, and diamonds) diamonds are also considered abiotic. On the basis of stage of development, natural resources are further classified in the following ways: 1. Potential resources 2. Actual resources 3. Reserve resources 4. Stock resources 1. Potential resources: 18 EVS Notes Compiled by Asst. Prof ANUSHA T The resources that remain in the earth's crust and may be used in the future is referred to as potential resources. Eg: - Petroleum, Solar Power, Wind Power, Mineral Oil,Paper etc. 2.Actual resources: The resources that have been surveyed, quantified, qualified and are currently being used for various purposes using technology are the actual resources. Eg: - Wood, Wind etc 3.Reserve resources: The part of an actual resource that can be developed profitably in the future is reserve resource. Eg: - Wind,soil, soil, mines, and trees etc 4. Stock Resources These are the resources that have been surveyed, but cannot be used due to lack technology are the stock resources. Eg: - Gases such as hydrogen, sea water etc. etc Land resources: Land resource refers to the land available for exploitation, like non-agricultural non lands for buildings, developing townships etc. Land resources (natural resources)occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. Land Use: Land use is the characterization of land based on what can be built on it and what the land can be used for. It is determining what sort of community, environment or settlement can be used on a total of arrangements, activities and inputs specific type of land. One definition of land use is “the total that people undertake in a certain land cover type.” Land use changes: Land use change is a process which transforms the natural landscape by direct human-induced human land use such as settlements, commercial and econo mic uses and forestry activities. economic Land Degradation: 19 EVS Notes Compiled by Asst. Prof ANUSHA T The change in the characteristic and quality of soil which adversely affect its fertility is called as Degradation. Land degradation is the major consequences of direct interference of human activities iin the natural phenomenon. Land degradation means: a) Loss of natural fertility of soil because of loss of nutrients b) Less vegetation covers c) Changes in the characteristic of soil d) Pollution of water resources from the contamination of soil through which watersweeps into ground or runoff to the water bodies. e) Changes in climatic conditions because of unbalance created in the environment. SOIL EROSION: The top layer of the soil is a valuable natural resource since all the nutrients required by plants are present in this layer. But due to many reasons, this highly fertile top soil is lost in a rapid rate.The process of detachment and transportation of soil, especially the fertile top soil, by natural agencies like water and wind is called soil erosion. Under normal conditions, natural soil erosionis fairly balanced with the process of soil formation. However, at present mainly due to decrease in plant cover, rate of erosion has exceeded the rate of soil formation. This is referred to as accelerated soil erosion. Soil erosion is of the following types: 1. Water erosion: Soil is transported by flowing water. The soil particles are also dislodged by falling rain drops and then transported by flowing rain water. This takes place by following threemethods. (a) Sheet erosion: Water removes the uppermost layer of the soil uniformly. (b) Rill erosion: An irregular network of grooves (drains) is formed as a result of continuous flow of water along the rough surface. (c) Gully erosion: Continuous rill erosion forms wider and deeper water channels. This is knownas gully erosion. 2. Wind erosion: This occurs commonly in dry regions like deserts. High velocity winds carry soil particles from one place to another. This occurs by following three methods. (a) Suspension: Wind blows fine soil particles in the form of dust particles from one place toanother. (b) Saltation: Medium sized soil particles are blown into the air. These colloid with one anotherand fall down. They are not carried to long distances. heavyy soil particles cannot be blown into the air. These (c) Surface creep: Large sized and heav areonly pushed due to great velocity of wind. 3. Stream bank or riparian erosion: The flood water strike constantly against the river banks. This results in cutting through the banks and new water channels are formed. The river may nowchange the course and water begins to flow in different directions. 20 EVS Notes Compiled by Asst. Prof ANUSHA T 4. Overgrazing and deforestation: The top soil gets removed and soil fertility decreases due to overgrazing. One of the major reasons for the formation of Rajasthan desert is said to be overgrazing. Besides these, cutting of trees in catchment areas (areas where rain water gets naturally collected and flows into river) has resulted in increased floods in plains. Methods of soil conservation by prevention of soil erosion: The main principles of reducing soil erosion and conserving soil are: 1) Protecting the top soil from direct impact of rain drops. This can be achieved by growingplants like grasses to form a continuous cover on soil. 2) Decreasing the speed of surface run-off of water by different methods like contour farming,strip cropping etc. 3) Reducing the velocity of wind by planting trees and shrubs in wows against wind direction toform 'wind breaks." 4) Increasing the moisture and organic matter content of soil by mulching increasing plant ever DESERTIFICATION: Desertification is a gradual process by which a fertile, productive land is converted into unproductive land and finally into barren desert-like area. Desertification is a form of land degradation by which fertile land becomes desert. According to Unity Nations Environment Program (UNEP), around 80% of the productive land arid regions of the world is estimated to be converting into deserts and in the arid and semi-arid around 600 million people are threatened by desertification. Globally, around 2 billion acres of land have become deserts in the past 50 years. The current rate of desertification is around 15 million acres per year, the worst being in Sub-saharan Africa. Desertification leads to decrease in crop yield, increase in hunger, Blooding due to absence of green cover, scarcity of water due to decrease in water resources, decrease in biodiversity and endangerment of species. Desertification is caused by the following factors: 1. Overgrazing: Animal grazing is a huge problem for many areas that are starting to becomedesert biomes. If there are too many animals that are overgrazing in certain spots, it makes it difficult for the plants to grow back, which hurts the biome and makes it lose its former greenglory. 2. Deforestation: When forests are cut down in large scale, the soil is exposed the plant cover.Soil gradually becomes drier and leads to desertification. 3. Farming practices: Intensive farming practices essentially strip the land of its resources,mainly nutrients, causing desertification. 4. Excessive use of fertilizers and pesticides: The use of excessive of fertilizers and pesticides to maximize crop yields in the short term often leads to significant damages to the soil. In the longrun, this may turn from arable into arid land, and it will no longer be suitable for farming purposes. 5. Overdrafting of groundwater: Groundwater is the freshwater found underground and also 21 EVS Notes Compiled by Asst. Prof ANUSHA T  one of the largest water sources. Over drafting is the process in which groundwater is extractedin excess of the equilibrium yield of the aquifer, that is pumping or the excessive pulling up of groundwater from underground aquifers. Its depletion causes desertification. Excessive use of groundwater for irrigation also increases soil salinisation and decreases its fertility. 6. Urbanization and other types of land development: As areas become more urbanized, there are fewer places for plants and green cover to grow, thus causing desertification. 7. Climate Change: Climate change plays a huge role in desertification. As the days get warmer and periods of drought become more frequent, desertification becomes more and more eminent. Control of Desertification: 1. Afforestation and planting of soil binding grasses can check soil erosion, floods and waterlogging. 2. Sustainable agricultural practices like crop rotation and mixed cropping which improves the fertility of the soil, controlling soil salinization and pollution by minimizing the use of irrigation and chemical fertilisers, etc. 3. Controlling climate change and global warming. 4. Proper management of urban areas to encourage atleast minimum green cover. Forest Resources: Forests are complex land ecosystems that support a wide variety of plants, trees and animals. animals It provides a lot of resources like fruits, timber, firewood,honey, herbal medicines etc. The forests also provide several raw materials for different manufacturing industries. Types of Forests:  Evergreen Forests: Evergreen forests or rainforests are normally known as blessing of the forests nature to mankind. An evergreen forest is a forest made up of evergreen trees trees. They occur across a wide range of climatic zones. A forest in which there is no complete, seasonal loss of leaves In India, evergreen forests are primarily located in states such as Karnataka and even Kerala Kerala. The Western Ghats are the primary location of the evergreen forest. The forests mainly contain trees such as rosewood, mahogany, and ebony.  Evergreen Forests are basically classified as a transitional type of forest Tropical Semi-Evergreen between tropical wet evergreen and tropical deciduous forests. In comparison to tropical 22 EVS Notes Compiled by Asst. Prof ANUSHA T  wet evergreen forests, these are drier places. The biotic components (producer, consumers, and decomposers) such as the rarest, most threatened, and endangered decomposers) primate species are found only in these forests. The abiotic factors (climate, temperature, soil, precipitation) such as humid and tropical climate, red soils, and heavy rainfall greatly influence the region.  Deciduous forests: These are the type of forests that shed their leaves every year during the period when days are getting shorter and colder, these tree leaves lose their color and fall off around Summer, as days become longer and warmer, autumn to winter. Slowly during Spring and Summer, they start to regrow their leaves. These forests are extra open and much less luxuriant than the equatorial evergreen forests.  Scrub Forests: low lying regions, there regions, This type of biome consists of desert region and areas of low-lying there are dense bushes which are growing over these places. Scrubland is an area with little precipitation and plenty of continuous winds, with a poor drainage system, and with medium to poor soil quality. Non timber forest Products Products: timber forest products are useful foods, substances, materials and/or commodities obtained Non-timber from forests other than timber. Harvest ranges from wild collection to farming. hey include fruits and nuts, vegetables, fish and game, medicinal plants, resin resins, essences and a range of barks and fibres such as bamboo, rattans, and a host of other palms and grasses. WATER RESOURCES: Water is the most abundant, inexhaustible renewable resource. It covers 70% of the globe in the form of oceans, rivers, lakes, etc. Of this 70%, only 3% is available as freshwater. From this 3%, roughly 2% is frozen in polar icecaps and only a fraction of the remaining 1% is used as drinking water (potable). 90% of the water is utilized for agricultural purposes in India. USE OF SURFACE AND GROUND WATER Consumptive use: In such uses, water is completely utilized and cannot be reused. Ex: Domestic, industrial and irrigation Non-consumptive use:In In such uses,water is not completely utilized and is reused Ex: Hydropower plant 23 EVS Notes Compiled by Asst. Prof ANUSHA T Other uses: Water is used for domestic purposes like drinking, bathing, cooking, washing. etc. Water is used in commercial establishments like hotels, theaters, educational institutions, offices, etc. Almost 60-70% 70% of fresh water is used for irrigation 20-30% of water is used for industrial operations by refineries, iron & steel industries, paper & pulp industries, etc. Water plays a key role in sculpting the earths surface, moderating climate and diluting pollutants. OVER-UTILIZATION UTILIZATION OF SURFACE & GROUND WATER: The rapid increase in population and industrial growth led to severe demand on water resources. After using all available surface water resources to the maximum, human beings began using groundwater to meet their needs. 1. The increased extraction of groundwater far in excess of the natural recharge led to decreased groundwater level. The erratic and inadequate rainfall caused reduction in storage of water in reservoirs. This also led to decrease of groundwater. 2. Building construction activities seal pe rmeable soil zone and reduce the area for permeable percolation of rainwater thereby increasing surface runoff. 3. If groundwater withdrawal rate is higher than recharge rate, sediments in aquifers get compacted resulting in sinking of overlaying land surface. This is called land subsidence which leads to structural damage in buildings, fracture in pipes and reverses the flow of canals leading to tidal flooding. 4. Over-utilization utilization of groundwater in arid and semi-arid semi arid regions for agriculture reservoir in the region causing problems like lowering of water disturbs equilibrium of reservoir table and decreased pressure in aquifers coupled with changes in speed and direction of water flow. 5. Over utilization of groundwater in coastal areas leads to rapid intrusion of salt water from the seaa thereby rendering it unusable for drinking and agriculture. 6. utilization of groundwater lads to decrease in water level thereby causing Over-utilization earthquake, landslides and famine. 7. Over-utilization drying up of dug wells as well as bore utilization of groundwater leads to drying-up bo wells. 8. Due to excess use of groundwater near agricultural fields, agricultural water that contains nitrogen as a fertilizer percolates rapidly and pollutes the groundwater thereby rendering the water unfit for potable use by infants. Flood and Droughts: Flood and drought are extreme negative situations caused due to water imbalances imbalances. These disasters though mainly natural have substantial human intervention triggering the impact. Flood 24 EVS Notes Compiled by Asst. Prof ANUSHA T and drought have occurred in the past as well, but its frequency has increased in the recent years due to changing climatic pattern. Causes of Flood There may be many causes of floods. The main causes are given below.  Ice and Snow Melt - Some mountains have ice caps on them. When this icecap melts in the summer season, it results in huge releases of water into the places that are usually dry.  Lack of Vegetation - vegetation can interrupt the flow of water. If there will be no vegetation, there will be nothing to slow down the flow of water.  Broken Dams - When heavy rain comes, comes, the water level increases in the dams and ageing dams can break and can unleash overflows of water in the household.  Heavy Rains - Whenever there is heavy rain and the drainage system is not proper, it may result in a flood or flood-like flood conditions.  Climate Change - Climate changes occur mainly due to human practices. Due to deforestation,, there will be more carbon dioxide in the atmosphere, which may lead to the melting of glaciers.  Emission of Greenhouse Gases - The burning of fossil fuels can lead to the emission of greenhouse gases which increase the atmospheric temperature and hence there will be melting of the glaciers. Effects of Flood  A flood can harm wildlife.  Flood carries contamination and can cause disease.  There may be a loss of goods and life in the flood.  A flood can cause soil erosion. Drought : Drought is defined as the prolonged period of dryness in the natural climate cycle. Causes of Drought : There are natural causes as well as human causes of drought. Human Causes Include the Following:  Overpopulation if too many people living in any particular area and using too much water can lead to scarcity of water.  Over cultivation of planting too many plants can use too much water. 25 EVS Notes Compiled by Asst. Prof ANUSHA T   Deforestation of plant roots can hold some amount of water, but cutting down them may lead to the condition of drought. Natural Causes Include the Following:  Less rainfall for weeks and years may be a major cause of the drought. Effects of Drought :  Drought can have various serious impacts on health, economy, and politics.  It may result in hunger.  Due to lack of water, there will not be enough food crops. Same conditions with the poultry and feed livestock.  Wildfire: Due to the drought, there will be a lack of moisture in the soil and environment and if there would be a hotter environment, it may lead to a fire in the forests.  The wildlife would ould be damaged due to a lack of enough water.  Water is essential to survive, if there would be a lack of drinking water, people may have various health-related related issues such as dehydration. Conflicts over Water: The Major Causes of Conflicts Over Water include inadequate water supply, dependence on one water source,, high population, modernization, poor relations between countries, etc. Different regions of the world are facing different types of water conflicts. Water conflicts are not ught but also due to various challenges in water supply, lack of requirements in only caused by drought fractures, and various factors. ENERGY RESOURCES: Energy resources are all forms of fuels used in the modern world, either for heating, generation of electrical energy, or for or other forms of energy conversion processes. There are 10 main different sources of energy that are used in the world to generate power. They are; 1. Solar Energy 2. Wind Energy 3. Geothermal Energy 4. Hydrogen Energy 5. Tidal Energy 6. Wave Energy 26 EVS Notes Compiled by Asst. Prof ANUSHA T  7. Hydro power energy 8. Biomass Energy 9. Nuclear Power 10. Fossil fuels (coal, oil & Natural Gas) Classification of Energy Resources The energy resources can be roughly classified into three categories, they are: 1. Renewable energy resources 2. Fossil energy resources 3. Nuclear energy resources 1. Renewable energy resources: The forms of energy that arenaturally replenished on our planet arerenewable energy resources. Eg: Hydropower, Biomass, Wind, Wave, Tidal, Solar, Geothermal energy etc. 2. Fossil energy resources: (Non-renewable) The forms of energy resources obtained from dead plant and animal deposits created over the long history of planet Earth are fossil energyresources. Eg: Fossil fuels - Coal, Oil and Natural gas. This energy resource is limited in supply and can get exhausted ed on continuous use i,e "Non-renewable" "Non in nature. 3.Nuclear Energy Resources esources: Deposits of certain radioactive elements present in Earth's crust are classified as nuclear energy fission based power plants to produce resources. These resources are used as fuel for nuclear fission-based nuclear energy. In this type of energy, using a small amount of raw material, large quantity of energy is produced. Even though, radioactive elements are limited in earth's crust and are non non- for a long time. So, it is also known as sustainable renewable, the energy sources will last long for energy resource. Further, these energy resources can be categorised into two types: Conventional sources of energy and non-conventional sources of energy. The energy sources which have been in common use are petrol, coal, wood, gas called conventional sources of energy. Electricity, etc.are examples of conventional sources of energy. 27 EVS Notes Compiled by Asst. Prof ANUSHA T The energy sources which are either new or have not been incommon use are non non-conventional sources of energy. Solar energy, windenergy, wave energy, geothermal energy, Biogas energy etc. are examples of non-conventional conventional sources of energy. Energy needs of growing economy: Energy is a critical component of a country's economic development. It is widely utilized in agricultural and allied fields such as the manufacturing and delivery of fertilizers, insecticides, and farm machinery.. It is necessary for homes for cooking, lighting, and warmth. Use Of Alternative energy Sources: Alternative energy is energy that does not come from fossil fuels,, and thus produces little to no greenhouse gases like carbon dioxide (CO2). This means that energy produced from alternative sources does not contribute to the greenhouse effect that causes climate change change. These energy sources are referred to as “alternative” because they represent the alternative sources of energy since to coal, oil, and natural gas,, which have been the most common sources the Industrial Revolution.. These fossil fuels emit high levels of CO2 when burned to produce energy and electricity. Alternative energy, however, should not be confused with renewable energy,, although many renewable energy sources can alsoalso be considered alternative. Solar power, for example, is both renewable and alternative because it will always be abundant and it emits no green house gases. ************* 28 EVS Notes Compiled by Asst. Prof ANUSHA T Notes Compiled by Asst Prof.Anusha T Page 29