The exquisite complexity of traits such as the vertebrate eye seems to pose a problem for evolution by natural selection. How do evolutionary biologists think that complex eyes evolved?
A) Complex eyes arose multiple times independently by a single mutation.
B) Intermediate forms of eyes were functional and selected for in the past but were selected for a function other than vision.
C) Eyes evolved in gradual steps, each of which was fully functional and adaptive in improving visual acuity.
D) Precursors to complex eyes were not adaptive and therefore were not subject to evolution by natural selection.

Question

Quizplus · Accepted Answer

Evolutionary biologists believe that complex eyes evolved in gradual steps, each of which was fully functional and adaptive in improving visual acuity. Intermediate forms of eyes provided an evolutionary advantage to organisms and were selected for over time. This process of gradual accumulation of beneficial traits is known as natural selection.

The Exquisite Complexity of Traits Such as the Vertebrate Eye