Micro-wear patterns found on the teeth of long-extinct specimens o

Official Answers and Explanations

1. According to the passage, Walker and Szalay disagree on which of the following points?
A. The structure and composition of australopithecine teeth
B. The kinds of conclusions that can be drawn from the micro-wear patterns on australopithecine teeth
C. The idea that fruit was a part of the australopithecine diet
D. The extent to which seed cracking and bone crunching produce similar micro-wear patterns on teeth
E. The function of the heavy enamel on australopithecine teeth
Supporting idea
This question refers to the first paragraph, which states that Walker does not agree with Szalay’s idea that the heavy enamel of australopithecine teeth is an adaptation to bone crunching.
A. According to the passage, Walker and Szalay disagree about the function of heavy enamel on the teeth, not the structure and composition of the teeth.
B. The passage does not indicate that Szalay has anything to say about the micro-wear patterns on the teeth.
C. Walker does, according to the passage, believe that australopithecines ate fruit, but it gives no evidence about whether Szalay believes that they ate at least some fruit.
D. According to the passage, Walker believes that seed cracking and bone crunching produce distinctive micro-wear patterns on teeth, but he does not necessarily believe that they are similar. The passage does not indicate Szalay’s position on the difference between micro-wear patterns.
E. Correct. The function of the heavy enamel on the teeth is the only idea about which the passage clearly indicates that Walker and Szalay disagree.
The correct answer is E.

2. The passage suggests that Walker’s research indicated which of the following about australopithecine teeth?
A. They had micro-wear characteristics indicating that fruit constituted only asmall part of their diet.
B. They lacked micro-wear characteristics associated with seed eating and bone crunching.
C. They had micro-wear characteristics that differed in certain ways from the micro-wear patterns of chimpanzees and orangutans.
D. They had micro-wear characteristics suggesting that the diet of australopithecines varied from one region to another.
E. They lacked the micro-wear characteristics distinctive of modern frugivores.
Inference
According to the passage, Walker’s research focuses on micro-wear patterns on the teeth of australopithecines. He draws several conclusions on the basis of these patterns: first, that australopithecines did not eat hard seeds; next, that they did not crunch bones; and finally, that they ate fruit.
A. The passage indicates that Walker’s observation of micro-wear patterns led him to conclude that australopithecines ate mostly fruit, not that fruitconstituted only a small part of their diet.
B. Correct. The first paragraph explains that Walker concluded from microwear patterns that australopithecines did not eat hard seeds and did not crunch bones; thus, his research must have indicated that they lacked micro-wear characteristics associated with such activities.
C. According to the passage, the opposite is true: based on the observation that their micro-wear patterns were indistinguishable from those of chimpanzees and orangutans, Walker concluded that australopithecines ate fruit.
D. The second paragraph of the passage complicates Walker’s view by suggesting that australopithecines’ diet might have varied from one region to another, but the passage says nothing about Walker’s research from which to infer that it indicated such variation.
E. Chimpanzees and orangutans are assumed to be frugivores, according to the passage, and Walker’s research indicated that australopithecine teeth had micro-wear characteristics identical to theirs.
The correct answer is B.

3. The passage suggests that which of the following would be true of studies of tooth micro-wear patterns conducted on modern baboons?
A. They would inaccurately suggest that some baboons eat more soft-bodied than hard-bodied insects.
B. They would suggest that insects constitute the largest part of some baboons’diets.
C. They would reveal that there are no significant differences in tooth microwear patterns among baboon populations.
D. They would inadequately reflect the extent to which some baboons consume certain types of insects.
E. They would indicate that baboons in certain regions eat only soft-bodied insects, whereas baboons in other regions eat hard-bodied insects.
Inference
The second paragraph states that modern baboons eat only soft-bodied insects
and so would not exhibit tooth abrasion to indicate that they were insectivores.
Thus, it would be difficult to determine exactly which soft-bodied insects they ate.
A. The passage states that baboons eat only soft-bodied insects—so it is in fact accurate to suggest that all baboons eat more soft-bodied than hard-bodied insects.
B. The passage says that baboons eat only soft-bodied insects. It also suggests that soft-bodied insects do not leave significant enough abrasions on baboons’ teeth to provide evidence of this aspect of their diet. Therefore, the tooth-wear patterns would give little or no information regarding what proportion of the baboons’ overall diet consists of insects.
C. The passage does not provide grounds for inferring anything about the differences, or lack thereof, among baboon populations in terms of tooth micro-wear patterns.
D. Correct. Because soft-bodied insects cause little tooth abrasion, microwear patterns would most likely not reflect the extent to which baboons consume soft-bodied insects.
E. The passage states that baboons eat only soft-bodied insects. Nothing in the passage suggests that baboons in certain regions eat hard-bodied insects.
The correct answer is D.

4. The passage suggests which of the following about the micro-wear patterns found on the teeth of omnivorous primates?
A. The patterns provide information about what kinds of foods are not eaten by the particular species of primate, but not about the foods actually eaten.
B. The patterns of various primate species living in the same environment resemble one another.
C. The patterns may not provide information about the extent to which a particular species’ diet includes seeds.D. The patterns provide more information about these primates’ diet than do the tooth micro-wear patterns of primates who are frugivores.
E. The patterns may differ among groups within a species depending on the environment within which a particular group lives.
Inference
This question focuses mainly on the end of the second paragraph, which states that the diets of current omnivorous primates vary considerably depending on the environments in which they live. It goes on to conclude that australopithecines, if they were omnivores, would similarly consume varied diets, depending on environment, and exhibit varied tooth micro-wear patterns as well. Thus, it is reasonable to conclude that any omnivorous primates living in different environments and consuming different diets would exhibit varied microwear patterns.
A. The passage indicates that the absence of certain types of micro-wear patterns can provide evidence about what foods a species does not eat. It also says that among omnivorous primates, one might expect to find considerable population variation in their tooth micro-wear patterns. Wherever micro-wear patterns are present, they provide evidence about what kinds of foods are eaten.
B. The passage suggests that various primate species living in the same environment might consume a variety of different diets, so there is no
reason to conclude that their micro-wear patterns would resemble one another.
C. The passage indicates that seed-eating produces distinctive micro-wear patterns, so the patterns, or lack thereof, on the teeth of any species would most likely provide information about the extent to which the species’ diet includes seeds.
D. The end of the first paragraph suggests that frugivores’ micro-wear patterns are distinctive; the passage provides no reason to believe that omnivores’ diets provide more information.
E. Correct. According to the passage, omnivorous primates of a particular species may consume different diets depending on where they live. Thus, their micro-wear patterns may differ on this basis.
The correct answer is E.

5. It can be inferred from the passage that if studies of tooth micro-wear patterns were conducted on modern baboons, which of the following would most likely be true of the results obtained?
A. There would be enough abrasion to allow a determination of whetherbaboons are frugivorous or insectivorous.
B. The results would suggest that insects constitute the largest part of the baboons’ diet.
C. The results would reveal that there are no significant differences in tooth micro-wear patterns from one regional baboon population to another.
D. The results would provide an accurate indication of the absence of some kinds of insects from the baboons’ diet.
E. The results would be unlikely to provide any indication of what inferences about the australopithecine diet can or cannot be drawn from micro-wear studies.
Inference
The second paragraph states that modern baboons eat soft-bodied insects but not hard-bodied ones—and it is hard-bodied insects, the passage suggests, that would cause particular micro-wear patterns on teeth. So the patterns on modern baboons’ teeth most likely do not exhibit the patterns indicating hard-bodied insect consumption.
A. The passage states that baboons’ consumption of soft-bodied insects would not show up in the patterns on their teeth—so the abrasion would most likely not provide enough information for a determination of whether baboons are frugivorous or insectivorous.
B. Since soft-bodied insects do not abrade the teeth significantly, it would be difficult to determine, based on micro-wear patterns, the part such insects play in the baboons’ diet. Furthermore, the passage does not suggest that micro-wear patterns can indicate the quantity of food an animal might have eaten.
C. There could be differences in tooth micro-wear patterns from one regional baboon population to another if they consumed anything in addition to softbodied insects.
D. Correct. Studying tooth micro-wear patterns on baboons’ teeth would most likely show that their teeth do not exhibit patterns typical of creatures that consume hard-bodied insects.
E. The passage suggests that based on results from micro-wear patterns on modern baboons’ teeth, one cannot infer from micro-wear studies whether australopithecines ate soft-bodied insects.
The correct answer is D.

6. It can be inferred from the passage that Walker’s conclusion about the australopithecine diet would be called into question under which of the following circumstances?A. The tooth enamel of australopithecines is found to be much heavier than
that of modern frugivorous primates.
B. The micro-wear patterns of australopithecine teeth from regions other than east Africa are analyzed.
C. Orangutans are found to have a much broader diet than is currently recognized.
D. The environment of east Africa at the time australopithecines lived there is found to have been far more varied than is currently thought.
E. The area in which the australopithecine specimens were found is discovered to have been very rich in soft-bodied insects during the period when australopithecines lived there.
Inference
The passage explains that Walker bases his conclusion about the frugivorous nature of the australopithecine diet on the fact that the micro-wear patterns on australopithecine teeth are indistinguishable from those of chimpanzees and orangutans, both of which are presumed to have frugivorous diets.
A. The passage indicates that Walker took into account the fact that australopithecines had relatively heavy tooth enamel and that he rejected the view that this heaviness was evidence against the hypothesis that they were frugivorous. For all we can tell from the information in the passage, the australopithecines’ tooth enamel was already known to be much heavier than that of modern frugivorous primates.
B. It could be the case that analyzing the micro-wear patterns of australopithecine teeth from other regions would yield the same data as those from east Africa.
C. Correct. According to the passage, Walker bases the conclusion that australopithecines were frugivorous on the similarity between their microwear patterns and those of modern chimpanzees and orangutans. If orangutans were found to have a diet that included a greater range of nonfruit foods than is currently recognized, then the correspondence between their micro-wear patterns and australopithecines’ micro-wear patterns would be consistent with the hypothesis that australopithecines’ diet was broader as well.
D. Even if the environment of east Africa were more varied, that would not mean the australopithecines necessarily ate a more varied diet. Many species that live in very varied environments specialize narrowly on particular foods in those environments.
E. Just because many soft-bodied insects might have been available toaustralopithecines does not mean that australopithecines ate them.
The correct answer is C.

7. The author of the passage mentions the diets of baboons and other living primates most likely in order to
A. provide evidence that refutes Walker’s conclusions about the foods making up the diets of australopithecines
B. suggest that studies of tooth micro-wear patterns are primarily useful for determining the diets of living primates
C. suggest that australopithecines were probably omnivores rather than frugivores
D. illustrate some of the limitations of using tooth micro-wear patterns to draw definitive conclusions about a group’s diet
E. suggest that tooth micro-wear patterns are caused by persistent, as opposed to occasional, consumption of particular foods
Evaluation
The passage discusses the diets of baboons and other living primates mainly in the second paragraph, which is concerned with explaining the limited utility of micro-wear studies.
A. The author raises some doubts about Walker’s conclusions but does not go as far as to try to refute them outright. The author argues only that, as the final sentence of the passage states, they may need to be expanded.
B. The author discusses the diets of baboons and other living primates in relation to micro-wear research on extinct primates. Nothing in the discussion suggests that micro-wear studies would be more useful for determining the diets of living primates than for providing evidence regarding the diets of earlier primates or of other types of animals. Furthermore, the mention of baboon diets suggests that micro-wear studies may not be very useful for determining the diets of some living primates.
C. The author leaves open the question of whether australopithecines were omnivores or frugivores. The passage suggests that some australopithecines might have been omnivores, if australopithecines’ diets varied according to the environments they inhabited. Walker’s conclusion regarding east
African australopithecines’ being frugivores might still hold, however.
D. Correct. The author refers to baboons’ diets and those of current omnivorous primates in order to suggest that there might be limitations to Walker’s use of tooth micro-wear patterns to determine australopithecines’ diet
E. The passage does not make a distinction between persistent and occasional consumption of particular foods.
The correct answer is D.