Explain.
(a) Population level
(b) Ecosystem
(c) Community
(d) Biosphere
(a) All members of a same species constitute the population level of organisation. For example, the population of humans in a particular area consists of all the individuals (males and females) living in that area. Thus, the total members of a particular species living in a particular area determine the population of that species.
(b) An ecosystem consists of several communities (biotic components) living in a particular area and their interactions with the non-living components (abiotic components). An ecosystem may be as small as an aquarium and as large as an ocean or a forest. It may be natural or man-made as a garden. There are many kinds of ecosystems such as lakes, rivers, seas and forests.
(c) A particular area in which a living organism lives and flourishes is called a habitat. The habitat of an organism consists of biotic and abiotic factors. The populations of various species of living organisms that live together in one particular habitat constitute a community. A single habitat may have single or more such communities of plants and animals.
(d) It is the lifeāsupporting zone of the Earth where all living things exist. It constitutes many ecosystems. It includes the atmosphere, hydrosphere and lithosphere. In a biosphere all biotic and abiotic factors depend on each other.