Paleontologist: Sifrhippus, a miniature horselike animal, lived about
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11 Mar 2024, 11:54
Paleontologist: Sifrhippus, a miniature horselike animal, lived about 56 million years ago. The average weight of Sifrhippus adults declined from 5.4 to 3.9 kilograms during a period of climatic warming that lasted about 175,000 years, then rose as the climate cooled again. The most likely explanation is that smaller mammals can shed heat more easily than larger ones—Sifrhippus must have adapted to the hot climate by shrinking because larger individuals would more often have died from overheating.
The paleontologist's hypothesis is the following:
The most likely explanation is that smaller mammals can shed heat more easily than larger ones—Sifrhippus must have adapted to the hot climate by shrinking
The support for the hypothesis is the following:
The average weight of Sifrhippus adults declined from 5.4 to 3.9 kilograms during a period of climatic warming that lasted about 175,000 years, then rose as the climate cooled again.
larger individuals would more often have died from overheating
So, the paleontologist reasons that, since Sifrhippus's size decreased when the climate warmed and increased when it cooled and since larger individuals would more often have died in hot conditions, the reason why Sifrhippus's size decreased is that "Sifrhippus ... adapted to the hot climate by shrinking."
Which of the following would, if true, most strongly support the paleontologist's hypothesis?
This question is a Strengthen question, and the correct answer will strengthen the support already provided or provide additional new support for the conclusion.
A. The climatic warming shrank Sifrhippus habitats, and larger habitats can generally support larger animals.
This choice weakens rather than strengthens the argument.
After all, if this choice is true, then it could be the case that, rather than to shed heat, Sifrhippus shrank because Sifrhippus habitats shank.
In other words, this choice indicates that there is a reasonable alternative explanation for Sifrhippus's shrinking and thus makes it less likely that the paleontologist's hypothesis is correct.
Eliminate.
B. Before the climate warming period, Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate.
This choice weakens rather than strengthens the argument.
After all, if Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate, then the types of changes in Sifrhippus's size that occurred when the climate did change were also going on when the climate didn't change. In other words, the effects occurred without the supposed cause.
The fact that the effects occurred without climate changes indicates that climate changes may not have been the cause even when climate changes did occur.
Eliminate.
C. Several species of small mammals went extinct during the period of climatic warming, while many larger species thrived.
This choice may seem to affect the strength of argument, but actually, it has no effect.
The passage states as fact that smaller animals can shed heat more easily and that larger animals would more often have died in hot conditions. So, even if this choice is true, and some particular species of small animals went extinct and some particular larger species thrived during periods of warming, it remains the case that shrinking could have helped Sifrhippus survive when it was hot.
Eliminate.
D. Sifrhippus populations increased in numbers during the period of climatic warming, then decreased again as the climate cooled.
This choice has no clear effect on the strength of the argument.
After all, there's no clear relationship between the populations increasing and decreasing and Sifrhippus's size decreasing and then increasing.
Eliminate.
E. During the climatic warming period, Sifrhippus adults weighed more, on average, in populations in cooler habitats.
This choice is interesting.
After all, it confirms the relationship between Sifrhippus's size and the climate by showing that, even within one time period, Sifrhippus adults were smaller where it was warm and larger where it was cooler.
By showing that the relationship between size and climate held even within one time period, this choice helps to eliminate other variables that could have changed over time and thus confirm that the key factor causing Sifrhippus to be smaller or larger was Sifrhippus's adaptation to different temperatures.
Thus, this choice strengthens the case for the hypothesis.
Keep.
Correct answer: E