GRE Prep: Hard-level Reading Comprehension Questions (Part 7)

GRE Prep: Hard-level Reading Comprehension Questions (Part 7)

In this post, we give you a short passage on evolutionary models followed by two difficult questions Try to annotate the passage as you go along so as not to lose track of the argumentative flow.

An important reason to believe that evolutionary processes can give rise to path-dependent change is provided by evolutionary models. Whilst some simple viability models may show the reverse trend, increasingly complex models support path dependency. The classic mathematical model of competing variants in evolutionary science is a simple viability model. In such a model, fitness is only dependent on the viability of the variant to reach reproductive age; such models quickly reach a stable equilibrium in which change is not path-dependent. However, these models provide heavily simplified representations of reality, omitting a large range of factors that influence fitness. As soon as more reality-like complexity is added to these models, the number of local optima and consequently possible paths increase. For example, as soon as fitness is made frequency-dependent and density-dependent, slightly different initial conditions can lead to drastically different results.


1. Which of the following sentence(s) reflect(s) the views of the author?

A) If reality were less complex, then there would be fewer reasons to believe that evolutionary change is path-dependent.

B) Some local optima are not captured by the classic model, and only appear in more complex models.

C) Scientists should, where possible, avoid simplifying evolutionary models.

D) Because viability models do not account for variants that do not reach reproductive age, their outcomes are less path-dependent than those of complex models that do account for such variants.

Explanation:

A) If reality were less complex, then there would be fewer reasons to believe that evolutionary change is path-dependent.

TRUE. The passage writes that “As soon as more reality-like complexity is added to these models, the number of local optima and consequently possible paths increase”—this means that if reality were less complex, path-dependency would decrease.

B) Some local optima are not captured by the classic model, and only appear in more complex models.

TRUE. The passage writes that the number of local optima increase in more complex models.

C) Scientists should, where possible, avoid simplifying evolutionary models.

FALSE. This is neither mentioned nor implied in the passage.

D) Because viability models do not take into account those variants that do not reach reproductive age, their outcomes are less path-dependent than those of complex models that do.

FALSE. This is not mentioned by the passage at all.

Answer: A and B.


2. Which of the following claims, if true, would strengthen the argument?

A) The outcomes of frequency-dependent models are robust under a wide range of variations in initial conditions.

B) Despite recent advances in population genetics, even the most advanced evolutionary models still omit a large proportion of factors that influence organismic fitness.

C) Recent studies show that even subtle tweaking of the parameters of simple viability models can cause these models to generate substantially different outcomes.

D) The outcomes of some density-dependent models remain unchanged even when starting conditions are changed drastically.

E) None of the above.

Explanation:

A) The outcomes of frequency-dependent models are robust under a wide range of variations in initial conditions.

This would weaken the argument, as it claims that complex models are not sensitive to small changes in initial conditions (opposite of the claim made in the passage).

B) Despite recent advances in population genetics, even the most advanced evolutionary models still omit a large proportion of factors that influence organismic fitness.

This neither strengthens nor weakens the argument.

C) Recent studies show that even subtle tweaking of the parameters of simple viability models can cause these models to generate substantially different outcomes.

This would strengthen the argument, as it holds that even the classical model shows path dependency. It thus goes even further than the arguments in the passage.

D) The outcomes of some density-dependent models remain unchanged even when starting conditions are changed drastically.

This would weaken the argument, as it claims that complex models are not sensitive to small changes in initial conditions (opposite of the claim made in the passage).

E) None of the above.

False.

Answer: C only.

If you found this series on difficult RC questions useful, why not browse through the other sections on TC and SE questions?