What does the Grants' study of medium ground finches tell us about evolution by means of natural selection?
A) New species cannot form.
B) A new species can form only when natural selection operates consistently in one direction for a few million years.
C) Evolution can change only single traits within a species.
D) New species normally take thousands to millions of years to arise because natural selection pressures operate in fits and starts.

Question

Quizplus · Accepted Answer

The Grants' study of medium ground finches on the Galápagos Islands demonstrated that natural selection pressures can fluctuate significantly over short periods, leading to rapid evolutionary changes. This suggests that the process of new species arising can indeed take a long time, as natural selection does not operate in a consistent direction but rather in "fits and starts," affecting various traits within a species.

What Does the Grants' Study of Medium Ground Finches Tell