Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized for You
we will pick new questions that match your level based on your Timer History
Track Your Progress
every week, we’ll send you an estimated GRE score based on your performance
Practice Pays
we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
Your score will improve and your results will be more realistic
Is there something wrong with our timer?Let us know!
The evolution of sex ratios has produced, in most plants and
[#permalink]
11 Aug 2020, 10:29
7
Expert Reply
2
Bookmarks
A
B
C
D
E
A
B
C
D
E
A
B
C
D
E
A
B
C
D
E
A
B
C
D
E
A
B
C
D
E
A
B
C
D
E
The evolution of sex ratios has produced, in most plants and animals with separate sexes, approximately equal numbers of males and females. Why should this be so? Two main kinds of answers have been offered. One is couched in terms of advantage to population. It is argued that the sex ratio will evolve so as to maximize the number of meetings between individuals of the opposite sex. This is essentially a "group selection" argument. The other, and in my view correct, type of answer was first put forward by Fisher in 1930. This "genetic" argument starts from the assumption that genes can influence the relative numbers of male and female offspring produced by an individual carrying the genes. That sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted. Suppose that the population consisted mostly of females: then an individual who produced sons only would have more grandchildren. In contrast, if the population consisted mostly of males, it would pay to have daughters. If, however, the population consisted of equal numbers of males and females, sons and daughters would be equally valuable. Thus a one-to-one sex ratio is the only stable ratio; it is an "evolutionarily stable strategy." Although Fisher wrote before the mathematical theory of games had been developed, his theory incorporates the essential feature of a game that the best strategy to adopt depends on what others are doing.
Since Fisher's time, it has been realized that genes can sometimes influence the chromosome or gamete in which they find themselves so that the gamete will be more likely to participate in fertilization. If such a gene occurs on a sex-determining (X or Y) chromosome, then highly aberrant sex ratios can occur. But more immediately relevant to game theory are the sex ratios in certain parasitic wasp species that have a large excess of females. In these species, fertilized eggs develop into females and unfertilized eggs into males. A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized. By Fisher's argument, it should still pay a \ female to produce equal numbers of sons and daughters. Hamilton, noting that the eggs develop within their host-the larva of another insect-and that the newly emerged adult wasps mate immediately and disperse, offered a remarkably cogent analysis. Since only one female usually lays eggs in a given larva, it would pay her to produce one male only, because this one male could fertilize all his sisters on emergence. Like Fisher, Hamilton looked for an evolutionarily stable strategy, but he went a step, further in recognizing that he was looking for a strategy
Question 1
00:00
A
B
C
D
E
Question Stats:
78% (02:54) correct
22% (03:39) wrong based on 58 sessions
HideShow
timer Statistics
21. The author suggests that the work of Fisher and Hamilton was similar in that both scientists
(A) conducted their research at approximately the same time ' (B) sought to manipulate the sex ratios of some of the animals they studIed (C) sought an explanation of why certain sex ratios exist and remain stable (D) studied game theory, thereby providing important groundwork for the later development of strategy theory (E) studied reproduction in the same animalspecies
Question 2
00:00
A
B
C
D
E
Question Stats:
63% (00:59) correct
37% (00:55) wrong based on 62 sessions
HideShow
timer Statistics
22. It can be inferred from the passage that the author considers Fisher's work to be
(A) fallacious and unprofessional (B) definitive and thorough (C) inaccurate but popUlar, compared with Hamilton's work (D) admirable, but not as up-to-date as Hamilton's work (E) accurate, but trivial compared with Hamilton's work
Question 3
00:00
A
B
C
D
E
Question Stats:
63% (01:24) correct
37% (01:12) wrong based on 52 sessions
HideShow
timer Statistics
23. The passage contains information that would answer which of the following questions about wasps?
I. How many eggs does the female wasp usually lay in a single host larrva? II. Can some species of wasp determine sex ratios among their offspring? III. What is the approximate sex ratio among the offspring of parasitic wasps?
(A) I only (B) II only (C) III only (D) I and II only (E) II and III only
Question 4
00:00
A
B
C
D
E
Question Stats:
87% (00:39) correct
13% (00:54) wrong based on 55 sessions
HideShow
timer Statistics
24. It can be inferred that the author discusses the genetic theory in greater detail than the group selection theory primarily because he believes that the genetic theory is more
(A) complicated (B) accurate (C) popular (D) comprehensive (E) accessible
Question 5
00:00
A
B
C
D
E
Question Stats:
80% (00:51) correct
20% (01:23) wrong based on 56 sessions
HideShow
timer Statistics
25. According to the passage, successful game strategy depends on
(A) the ability to adjust one's behavior in light of the behavior of others (B) one's awareness that there is safety in numbers (C) the degree of stability one can create in one's immediate environment (D) the accuracy with which one can predict future events (E) the success one achieves in conserving and storing one's resources
Question 6
00:00
A
B
C
D
E
Question Stats:
54% (01:18) correct
46% (01:03) wrong based on 54 sessions
HideShow
timer Statistics
26. It can be inferred from the passage that the mathematical theory' of games has been
(A) developed by scientists with an interest in genetics (B) adopted by Hamilton in his research (C) helpful in explaining how genes can sometimes influence gametes (D) based on animal studies conducted prior to 1930 (E) useful in explaining some biological phenomena
Question 7
00:00
A
B
C
D
E
Question Stats:
77% (01:20) correct
23% (01:24) wrong based on 57 sessions
HideShow
timer Statistics
27. Which of the following is NOT true of the species of parasitic wasps discussed in the passage?
(A) Adult female wasps are capable of storing sperm. (B) Female wasps lay their eggs in the larvae of other insects. (C) The adult female wasp can be fertilized by a male that was hatched in the same larva as herself. (D) So few male wasps are produced that extinction is almost certain. (E) Male wasps do not emerge from their hosts until they reach sexual maturity.
Re: The evolution of sex ratios has produced, in most plants and
[#permalink]
02 Jan 2021, 03:32
1
Expert Reply
Although Fisher wrote before the mathematical theory of games had been developed, his theory incorporates the essential feature of a game that the best strategy to adopt depends on what others are doing.
26. It can be inferred from the passage that the mathematical theory' of games has been
(A) developed by scientists with an interest in genetics
Not stated
(B) adopted by Hamilton in his research
He wrote before the theory itself came out
(C) helpful in explaining how genes can sometimes influence gametes
Out of scope
(D) based on animal studies conducted prior to 1930
This was fort another scope
(E) useful in explaining some biological phenomena
Yes. We can infer this from the highlighted part above
Re: The evolution of sex ratios has produced, in most plants and
[#permalink]
04 Aug 2021, 00:50
2
1.The author suggests that the work of Fisher and Hamilton was similar in that both scientists
(A) conducted their research at approximately the same time Crossed out. We only have one specific year - 1930, and nothing else. Moreover, this statement, 'Since Fisher’s time, it has been realized that genes can sometimes...', implies that some time has passed between the discussion offered in the second paragraph and the explanation offered by Fisher (in the first paragraph).
(B) sought to manipulate the sex ratios of some of the animals they studied Crossed out. New information. Nothing of the sort is mentioned in the passage.
(C) sought an explanation of why certain sex ratios exist and remain stable YES And that's what the passage is all about - a discussion of the evolution of sex ratios, and the explanations of two people in particular.
(D) studied game theory, thereby providing important groundwork for the later development of strategy theory Crossed out. New information. (and game theory itself isn't even the primary focus of the passage)
(E) studied reproduction in the same animal species Crossed out. New information. Nothing of the sort is mentioned in the passage.
*****
It can be inferred from the passage that the mathematical theory of games has been
(A) developed by scientists with an interest in genetics Crossed out. New information. Nothing of the sort is mentioned in the passage.
(B) adopted by Hamilton in his research Crossed out. Bait choice. It's mentioned that "he went a step further in recognizing that he was looking for a strategy", but looking for a strategy DOES NOT NECESSARILY mean that "the mathematical theory of games has been adopted by Hamilton in his research". Strategies are a part of Game Theory, not GT itself. The choice is trying to create that information in your head (and thus tricking you into choosing it) when the actual, precise information is nowhere in the passage.
(C) helpful in explaining how genes can sometimes influence gametes Crossed out. I see that this is the second most opted choice. But it's wrong. In the third sentence of the second paragraph, "But more immediately relevant to game theory..." implies that the idea that "genes can sometimes influence the chromosome or gamete" is also relevant to game theory. "More immediately relevant" means that the theory can be more readily applied to the latter subject (large excess of females in parasitic wasps), and it means nothing more. 'Readiness of application' DOES NOT equal to the 'application' itself. If activity X CAN be applied to stuff Z, and that's all what has been said, then then doesn't necessarily mean that activity X HAS been applied to stuff Z. By choosing C, you're saying that 'the mathematical theory of games has been helpful in explaining how genes can sometimes influence gametes'. That implies APPLICATION. But only the 'readiness of application' is stated in the passage, not the (information about) any application itself!
(D) based on animals studies conducted prior to 1930 Crossed out. New information. Nothing of the sort is mentioned in the passage. (Even contradicts the given information - Fisher's explanation was given in 1930, "before the mathematical theory of games had been developed")
(E) useful in explaining some biological phenomena YES You could either get here by reduction, or by pushing more analysis into the choices. From all that's been said in the passage, this is the ONLY choice that fits. We can safely say that "the mathematical theory of games has been useful in explaining some biological phenomena".
Re: The evolution of sex ratios has produced, in most plants and
[#permalink]
27 Aug 2022, 08:06
Hello from the GRE Prep Club VerbalBot!
Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
gmatclubot
Re: The evolution of sex ratios has produced, in most plants and [#permalink]
11 Aug 2020, 10:29
78% (02:54) correct
