Q19 of 26 Page 1

(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.


(a) The sixth extinction presently in progress is different from the previous episodes because the current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times and human activities are responsible for the faster rate.


(b) Negative effects of loss of biodiversity –


• Humans derive countless direct economic benefits from nature – food, medicines, firewood, etc. and biodiversity loss can lead to deprivation of these benefits.


• Loss in biodiversity can lead to reduced to oxygen production by green plants.


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