Read the passage and answer the following questions:
Adding to the grim scenario of extinctions is the fact that more than 15,500 species world-wide are facing the threat of extinction. From a study of the history of life on earth through fossil records, we learn that large-scale loss of species like the one we are currently witnessing have also happened earlier, even before humans appeared on the scene. During the long period (> 3 billion years) since the origin and diversification of life on earth there were five episodes of mass extinction of species. How is the 'Sixth Extinction' presently in progress different from the previous episodes? The difference is in the rates; the current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times and our activities are responsible for the faster rates. Ecologists warn that if the present trends continue, nearly half of all the species on earth might be wiped out within the next 100 years.
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The 'Sixth Extinction' presently in progress is different from the five earlier episodes of mass extinction of species.
Reason (R): Fossil records show that large-scale loss of species, like the one we are witnessing now, also happened earlier, even before humans appeared on the scene.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Both (A) and (R) are true but (R) is not the correct explanation of (A).
Assertion (A): The ‘Sixth Extinction’ presently in progress is different from the five earlier episodes of mass extinction of species. — True. The passage states that “The difference is in the rates; the current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times and our activities are responsible for the faster rates.” A is about how the present extinction differs from the earlier ones.
Reason (R): Fossil records show that large-scale loss of species, like the one we are witnessing now, also happened earlier, even before humans appeared on the scene. — True. The passage states that from fossil records “we learn that large-scale loss of species like the one we are currently witnessing have also happened earlier, even before humans appeared on the scene.” There were five such episodes in more than 3 billion years. R is about what the present extinction has in common with the past.
Why R does not explain A? R only tells us that mass extinctions are not new. It points to a likeness, so it cannot be the reason for a difference. What makes the Sixth Extinction different is its rate, which is 100 to 1,000 times faster than in pre-human times because of human activities. R says nothing about this rate, so it is not the correct explanation of A.