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  3. Micro-wear patterns found on the teeth of long-extinct specimens of the primate species australopithecine may provide evidence a

Micro-wear patterns found on the teeth of long-extinct specimens of the primate species australopithecine may provide evidence a

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问题 Micro-wear patterns found on the teeth of long-extinct specimens of the primate species australopithecine may provide evidence about their diets. For example, on the basis of tooth micro-wear patterns, Walker dismisses Jolly’s hypothesis that australopithecines ate hard seeds. He also disputes Szalay’s suggestion that the heavy enamel of australopithecine teeth is an adaptation to bone crunching, since both seed cracking and bone crunching produce distinctive micro-wear characteristics on teeth. His conclusion that australopithecines were frugivores (fruit eaters) is based upon his observation that the tooth micro-wear characteristics of east African australopithecine specimens are indistinguishable from those of chimpanzees and orangutans, which are commonly assumed to be frugivorous primates.
However, research on the diets of contemporary primates suggests that micro-wear studies may have limited utility in determining the foods that are actually eaten. For example, insect eating, which can cause distinct micro-wear patterns, would not cause much tooth abrasion in modern baboons, who eat only soft-bodied insects rather than hard-bodied insects. In addition, the diets of current omnivorous primates vary considerably depending on the environments that different groups within a primate species inhabit; if australopithecines were omnivores too, we might expect to find considerable population variation in their tooth micro-wear patterns. Thus, Walker’s description of possible australopithecine diets may need to be expanded to include a much more diverse diet.
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?
选项 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.
答案C
解析 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 onto 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 micro-wear patterns and those of modern chimpanzees and orangutans. If orangutans were found to have a diet that included a greater range of non-fruit 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 to australopithecines does not mean that australopithecines ate them.
The correct answer is C.
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