For much of the twentieth century, paleontologists theorized that dinosaurs, like reptiles, were ectothermic, their body temperature regulated externally. These scientists, however, based their conclusions on faulty reasoning, claiming that scaly skin was common to all ectotherms (amphibians, which are ectothermic, do not have scaly skin) and that the dinosaur’s size could account for ectothermy (some adult dinosaurs weighed as little as ten pounds). Supplanting this theory is an entirely new line of thought: dinosaurs were actually mesothermic, neither warm- nor cold-blooded. By taking this middle ground, some paleontologists maintain that dinosaurs were faster than similar-sized reptiles yet did not require as much food as similar-sized mammals. To substantiate this theory, paleontologists intend to study how birds, dinosaurs’ closest extant relatives, might have at one time been mesothermic.
For the following question, consider each of the choices separately and select
all that apply.
Which of the following does the passage imply regarding birds?
A. They hold value in their evolutionary proximity to dinosaurs.
B. They require more food than a similarly-sized mammal.
C. Over time they might have undergone a change in how they regulate body temperature.
The two parts in parentheses serve to do which of the following?
A. Summarize two claims that the author of the passage ultimately repudiates
B. Highlight commonalities between amphibians and dinosaurs
C. Provide rebuttals to commonly held views regarding physical aspects of dinosaurs
D. Describe a recent theory that the author of the passage supports
E. Furnish information regarding contradictory notions of dinosaur behavior
For the following question, consider each of the choices separately and select
all that apply.
Based on the information in the passage, it can be inferred that which of the following is a possible benefit conferred by mesothermy?
A. Controlling for size, it allows for greater speed than does ectothermy.
B. Controlling for size, it leads to less dependence on food than does ectothermy.
C. It allowed prehistoric birds to fly.