CAT 2017 Question Paper | Verbal Slot 1

CAT Questions

CAT Previous Year Papers give you a flavour of the CAT Exam and type of questions asked in the CAT Question Paper. Your online CAT preparation is incomplete without going through the actual questions asked in the CAT Examover the years. Don't fall short in covering this important element of CAT preparation and start with this Reading Comprehension question taken from CAT 2017 Question Paper.
To find more questions to practice, visit 2IIM's Question Bank!

---

Scientists have long recognised the incredible diversity within a species. But they thought it reflected evolutionary changes that unfolded imperceptibly, over millions of years. That divergence between populations within a species was enforced, according to Ernst Mayr, the great evolutionary biologist of the 1940s, when a population was separated from the rest of the species by a mountain range or a desert, preventing breeding across the divide over geologic scales of time. Without the separation, gene flow was relentless. But as the separation persisted, the isolated population grew apart and speciation occurred.

In the mid-1960s, the biologist Paul Ehrlich - author of The Population Bomb (1968) - and his Stanford University colleague Peter Raven challenged Mayr's ideas about speciation. They had studied checkerspot butterflies living in the Jasper Ridge Biological Preserve in California, and it soon became clear that they were not examining a single population. Through years of capturing, marking and then recapturing the butterflies, they were able to prove that within the population, spread over just 50 acres of suitable checkerspot habitat, there were three groups that rarely interacted despite their very close proximity.

Among other ideas, Ehrlich and Raven argued in a now classic paper from 1969 that gene flow was not as predictable and ubiquitous as Mayr and his cohort maintained, and thus evolutionary divergence between neighbouring groups in a population was probably common. They also asserted that isolation and gene flow were less important to evolutionary divergence than natural selection (when factors such as mate choice, weather, disease or predation cause better-adapted individuals to survive and pass on their successful genetic traits). For example, Ehrlich and Raven suggested that, without the force of natural selection, an isolated population would remain unchanged and that, in other scenarios, natural selection could be strong enough to overpower gene flow...

Question 2 : All of the following statements are true according to the passage EXCEPT

1. Gene flow contributes to evolutionary divergence.
2. The Population Bomb questioned dominant ideas about species diversity.
3. Evolutionary changes unfold imperceptibly over time.
4. Checkerspot butterflies are known to exhibit speciation while living in close proximity.

---

---

Video Explanation

---

---

Explanatory Answer

The book—The Population Bomb—only challenged Mayr's ideas about speciation, and not all the dominant ideas about species diversity. It only argued that ‘isolation and gene flow were less important to evolutionary divergence than natural selection’, not that they were irrelevant.

Also note that the above implies that gene flow contributes to evolutionary divergence. Ehrlich and Raven do not contest the idea that evolutionary changes unfold imperceptibly over time. The passage states that there were three groups of checkerspot butterflies ‘that rarely interacted despite their very close proximity’.

---

The question is "All of the following statements are true according to the passage EXCEPT"

Hence, the answer is The Population Bomb questioned dominant ideas about species diversity.

Choice B is the correct answer.