This unit deals with
the meaning of ecosystems and its components. The energy flow among the biotic
and abiotic environment is discussed. It also explains the significance of
biodiversity and its loss. Both terrestrial and aquatic biomes are dealt in
Biosphere, the fourth
sphere of the Earth, is a life supporting layer that exists on the earth’s
surface. This layer on earth encompasses the Lithosphere, Hydrosphere and
Atmosphere. It includes flora and fauna that thrive on or near the earth’s
surface. The vertical range of the biosphere is approximately 20 km, which is
measured from the ocean floor to the troposphere. However, most plants and
animals live in a very narrow section for about 1 km above and below the Mean
Sea Level (MSL). Biosphere is made up of different ecosystems and biomes.
All living things, large or small, are grouped into species. The
area in which an animal, plant or micro organism lives is called its habitat.
A wide variety of plants and animals live in a particular habitat known as biodiversity.