Question

(a) Since the origin and diversification of life on earth there had been five episodes of mass extinctions. How is the sixth extinction presently in progress, different from the previous episodes and why ?
(b) Mention any two negative effects of loss of biodiversity in the region where it occurs.

Answer 1

(a) The current extinction rate are estimated to be 100 to 1000 times faster than in the pre-human times , because of human activities 
(b) (i) Decline in plant production
(ii) Lowered resistance to environmental perturbations such as drought
(iii) Increased variability in certain ecosystem processes such as plant productivity / water use / pest and disease cycles