(i) The system formed by the interaction of all living organisms with each other and with the physical and chemical factors of the environment in which they live, all linked by the transfer of energy and material, is called an ecosystem.
(ii) The basic components and organisms that are naturally present in the environment without any human involvement, like the land, water, air, plants and animals, comprise the natural environment.
(iii) Components of the environment include
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Natural Components (Air, Water, Land and Living things)
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Human-made Components (Components created by human beings)
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Human Components (Human populations)
(iv) Four examples of the human-made environment are buildings, parks, industries and bridges.
(v) The solid crust or the hard top layer of the earth is called the lithosphere. It is made up of rocks and minerals and is covered by a thin layer of soil. It is an irregular surface with various landforms like mountains, plateaus, plains, etc.
(vi) Plants and animals are the two major components of the biotic environment.
(vii) Biosphere or the living world is the narrow zone of earth where land, water and air interact with each other to support life. The plant and animal kingdoms together form the biosphere.
