历年GRE考试真题精选系列二十二
Although scientists observe that an organ-ism’s behavior falls into rhythmic patterns,
they disagree about how these patterns are
affected when the organism is transported to a
(5) new environment. One experimenter, Brown,
brought oysters from Connecticut waters to
Illinois waters. She noted that the oysters
initially opened their shells widest when it was
high tide in Connecticut, but that after fourteen
(10)days their rhythms had adapted to the tide
schedule in Illinois. Although she could not
posit an unequivocal causal relationship
between behavior and environmental change,
Brown concluded that a change in tide schedule
(15)is one of several possible exogenous influences
(those outside the organism) on the oysters’
rhythms. Another experimenter, Hamner,
however, discovered that hamsters from Cali-
fornia maintain their original rhythms even
(20)at the South Pole. He concluded that endo-
genous influences (those inside the organism)
seem to affect an organism’s rhythmic behavior.
17. All of the following could be considered
examples of exogenous influences on an
organism EXCEPT the influence of the
(A) level of a hormone on a field mouse’s readi-
ness for mating
(B) temperature of a region on a bear’s hiber-
nation
(C) salt level of a river on a fish’s migration
(D) humidity of an area on a cat’s shedding of
its fur
(E) proximity of an owl on a lizard’s searching
for food
18. Which of the following statements best describes
the conclusion drawn by Brown (lines 14-17)?
(A) A change in tide schedule is the primary
influence on an oyster’s rhythms.
(B) A change in tide schedule may be an
important exogenous influence on an
oyster’s rhythms.
(C) Exogenous influences, such as a change in
tide schedule, seldom affect an oyster’s
rhythms.
(D) Endogenous influences have no effect on an
oyster’s rhythms.
(E) Endogenous influences are the only
influences on an oyster’s rhythms.
历年GRE考试真题精选系列二十二
19. The passage suggests that Brown’s study wassimilar to Hamner’s in which of the following
ways?
Ⅰ. Both experimenters discovered that a
new environment had a significant effect
on an organism’s behavioral rhythms.
Ⅱ. Both experimenters observed an
organism’s behavioral rhythms after the
organism had been transported to a new
environment.
Ⅲ. Both experimenters knew a organism’s
rhythmic patterns in its original
environment.
(A)Ⅰonly
(B)Ⅱonly
(C)Ⅰand Ⅱ only
(D)Ⅱand Ⅲ only
(E)Ⅰ,Ⅱ,and Ⅲ
20. Which of the following, if true, would most
weaken Brown’s conclusion?
(A) The oysters gradually closed their shells
after high tide in Illinois had passed.
(B) The oysters’ behavioral rhythms main-
tained their adaptation to the tide
schedule in Illinois throughout thirty
days of observation.
(C) Sixteen days after they were moved to
Illinois, the oysters opened their shells
widest when it was high tide in
Connecticut.
(D) A scientist who brought Maryland oysters
to Maine found that the oysters opened
their shells widest when it was high tide
in Maine.
(E) In an experiment similar to Brown’s, a
scientist was able to establish a clear
causal relationship between environ-
mental change and behavioral rhythms.
17.A 18.B 19.D 20.C
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