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Environmental Sustainability BLOCK 2 FUNDAMENTALS OF ECOLOGY 89 Fundamentals of Ecology BLOCK 2 FUNDAMENTALS OF ECOLOGY Ecology is the study of the environment in which an organism lives. Ecology is the study of the interactions of organisms with their surrounding environment. Every living species whether plant, animal or microbe along with their physical and chemical environment could be part of ecological studies. The study of ecology is of quite significance which can help in better understanding of consequences of human interventions at various levels and can also suggest suitable solutions for the unsustainable changes occurring in nature. The study of ecology includes levels of organization in ecology, environmental factors and different types of biotic relationships. Ecology is studied at various levels of organization from species level to biome. The population is studied as a collective group of organisms of the same species which occupy a particular space at a particular time. The population parameters include density, natality, mortality, age distribution, biotic potential, dispersion, and growth form. As regards the community organisation, a group of populations of different species interact in a given area. Various interspecific and intraspecific interactions occur among organisms. The world’s major communities, called biomes are classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment. Unit 5 “Ecology” discusses the concepts in ecology, its scope, levels of organization in ecology, environmental factors and different types of biotic relationships. Unit 6 “Population Parameters and Regulation” discusses the parameters of population estimation, demographic techniques, various approaches employed for population regulation and evolutionary implications of natural regulation. Unit 7 “Community Organisation and Interaction among Organisms” deals with the processes that affect community organisation and also various interspecific and intraspecific interactions among organisms. Unit 8 “Ecological Succession and Climax” discusses the causes of succession, types of succession, processes of succession and the ecological adaptation in hydrophytes, mesophytes, halophytes and animals. Unit 9 “Major Biomes of the World” delves on the major biomes of the world and characteristic features of the aquatic and terrestrial biomes. We hope that after studying this block, you will acquire an understanding of the concept and scope of ecology, biotic relationships, population parameters and community organization. Wishing you success in this endeavour! 90 UNIT 5 ECOLOGY Ecology Structure 5.1 Introduction 5.2 Objectives 5.3 Basic Concepts in Ecology 5.4 Scope of Ecology 5.5 Levels of Organization in Ecology 5.6 Applied Ecology 5.7 Environmental Factors 5.7.1 Climatic Factors 5.7.2 Topographic Factors 5.7.3 Edaphic Factors 5.7.4 Biotic Factors 5.8 Biotic Relationships 5.9 Let Us Sum Up 5.10 Key Words 5.11 Suggested Further Reading/References 5.12 Answers to Check Your Progress 5.1 INTRODUCTION Ecology word has its origin in two Greek words; ‘Oikos’= house and ‘Logos’= to study. Ecology is the study of environment in which an organism lives. Reiter (1868) has coined the term for the first time. Haeckel (1886) first used the word ‘Ecology’ and defined its meaning as relations of organisms to their surrounding outer world and to organic and inorganic conditions of existence which now could be called as biotic and abiotic factors to which organisms interact with. Among so many definitions of ecology available, the most common could be considered is the study of interactions of organisms with their surrounding environment. Every living species whether plant, animal or microbe along with their physical and chemical environment could be part of ecological studies. Humans are affecting environment in myriad ways. In this regard, study of ecology is of quite significance which can help in better understanding of consequences of human interventions at various levels and can also suggest suitable solutions for the unsustainable changes occurring in the nature. In this unit, we would be discussing the concepts in ecology, its scope, levels of organization in ecology, environmental factors and different types of biotic relationships. 5.2 OBJECTIVES After studying this unit, you should be able to: • explain the basic concepts of ecology; • describe the various levels of organization in ecology; • explain different environmental factors; and 91 Fundamentals of Ecology • describe different types of biotic relationships. 5.3 BASIC CONCEPTS IN ECOLOGY According to Misra (1991), there are four basic concepts in ecology. These are explained briefly: 1. Holism: This term was coined by J.C. Smuts in 1926 in the book ‘Holism and Evolution’. W. Ophuls (1974) suggested that Holism is the base of Ecology. The various units of ecology from lower to higher levels are as follows: individual, population, community, ecosystem, biome, biosphere. Holism suggests that each unit is built as a whole by interactions of lower- level wholes into higher level wholes. 2. Ecosystem: This term was coined by A.G. Tansley (1935). Ecosystem forms the structural and functional unit of nature where both biotic and abiotic components interact and work in a complex. 3. Succession: It is a long-term process where an ecosystem is converted into a higher biomass rich and trophically diverse stable ecosystem. This occurs due to change in environment which influences development of organisms and in turn, organisms also affect the environment by their activities. Due to this dynamism in both environment and organisms, process of succession starts and keeps going on till a stable community is developed. The final stabilized stage is known as climax. 4. Conservation: It is the necessity for living in a sustainable manner. Various factors of ecosystem interact with each other and regulate themselves in order to keep the ecosystem healthy for long. Due to degrading environment, pollution, climate change and some other problems, conservation strategies are required for their effective solution and maintenance of a healthy planet. 5.4 SCOPE OF ECOLOGY Ecology is a multi-disciplinary science focusing on diverse spatial and temporal scales. Study of ecology could be done at various levels starting from nucleic acids and proteins in biochemistry and molecular biology, cells in cellular biology, organisms in botany, zoology, microbiology with details in morphology, physiology, taxonomy, genetics, evolution, developmental biology, toxicology, etc. and other sub-division levels such as phycology, mycology, bacteriology, virology, ornithology, etc. Ecology could also be studied at the level of population, community and ecosystem. Human ecology itself is a vast field of investigation and so is “Biome Ecology”. Ecology not only involves biotic components but also the abiotic components such as various environmental factors, thus study of geography, geology, meteorology, pedology. geochemistry and paleoscience are also under scope of ecology. Study of an organism with respect to its environment such as changes in behavior or changes at genetic level are part of ecology. An ecologist must also have knowledge about mathematics, statistics, physics, chemistry and computational biology. Further, applied ecology is studied along with theoretical ecology to solve various environmental problems of an area. Thus, Ecology is rightly considered as a “Holistic Science”. 92
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