The Galapagos finches, made famous by Darwin, are still teaching biologists about evolution. A long-term study tracking individual birds across decades has documented beak-size shifts in response to drought conditions — measurable evolution occurring within a few years rather than across millennia. Evolution, this work suggests, is not always slow; it can be rapid when selection pressure is intense.
Which choice best states the main idea of the text?
- A
Evolution is always slow.
- B
Darwin's theory is outdated.
- Ccheck_circle
Studies of Galapagos finches show that evolution can occur on observable timescales when selection pressure is strong.
- D
Beak size has no effect on survival.
Explanation
The passage's central claim is that finch studies reveal rapid evolution under pressure — B. A, C, and D contradict the text.