Question

Ecologists warn that if the current rate of species extinction continues, then nearly___(A)____on earth might go extinct within the next_____(B)___years.

• A. A - half of all the species, B - 200
• B. A - all the species, B - 100
• C. A - half of all the species, B - 500
• D. A - half of all the species, B - 100

Answer 1

The correct option is D A - half of all the species, B - 100

Our planet Earth is endowed with enormous and rich biodiversity.

But unfortunately, this biological wealth is rapidly declining due to human activities.

Earth has witnessed five episodes of mass extinction of species in the past and right now the sixth one is in progress.

Extinction of species refers to the complete disappearance of all members of a species from every part of the world.

The rate of extinction of species in the sixth mass extinction is estimated to be 100 to 1,000 times faster than the earlier mass extinctions. This is mainly due to human activities.

The IUCN Red List (2004) documents the extinction of 784 species in the last 500 years which is quite alarming.

Some examples of recent extinctions include dodo (Mauritius), quagga (Africa), thylacine (Australia), Steller’s Sea Cow (Russia) and three subspecies (Bali, Javan, Caspian) of tiger.

Nearly 27 species have disappeared in the last twenty years. It is estimated that 15,500 species worldwide are facing the threat of extinction.

Ecologists warn that if the current rate of species extinction continues, then nearly half of all the species on earth might go extinct within the next 100 years.