NCERT Book Class 12 Biology Chapter 13 Biodiversity and Conservation

CHAPTER 13

BIODIVERSITY AND
CONSERVATION

13.1 Biodiversity

13.2 Biodiversity Conservation If an alien from a distant galaxy were to visit our planet
Earth, the first thing that would amaze and baffle him
would most probably be the enormous diversity of life
that he would encounter. Even for humans, the rich variety
of living organisms with which they share this planet never
ceases to astonish and fascinate us. The common man
would find it hard to believe that there are more than
20,000 species of ants, 3,00,000 species of beetles, 28,000
species of fishes and nearly 20,000 species of orchids.
Ecologists and evolutionary biologists have been trying
to understand the significance of such diversity by asking
important questions– Why are there so many species?
Did such great diversity exist throughout earth’s history?
How did this diversification come about? How and why
is this diversity important to the biosphere? Would it
function any differently if the diversity was much less?
How do humans benefit from the diversity of life?

13.1 BIODIVERSITY
In our biosphere immense diversity (or heterogeneity)
exists not only at the species level but at all levels of
biological organisation ranging from macromolecules
within cells to biomes. Biodiversity is the term popularised
by the sociobiologist Edward Wilson to describe the