The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?
A) Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.
B) Forelimb evolution was adaptive in people and bats, but not in whales.
C) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
D) Genes mutate faster in whales than in humans or bats.
E) Whales are not properly classified as mammals.

Question

Quizplus · Accepted Answer

Natural selection in different environments (terrestrial for humans and bats, aquatic for whales) drives the evolution of anatomical features to adapt to those environments. This explains why the forelimbs of whales, which evolved to adapt to aquatic life, differ significantly from those of humans and bats, which retained more of the terrestrial adaptations of their common ancestor.

The Upper Forelimbs of Humans and Bats Have Fairly Similar