Whales and pigs diverged about 80 million years ago.Suppose a DNA sequence has had 48 changes between whales and pigs.The same DNA sequence has had 6 changes between two different species of whales.Assuming a molecular clock is operating, the whale species diverged _______ million years ago.
A) 5
B) 10
C) 20
D) 30
E) 40

Question

Quizplus · Accepted Answer

If whales and pigs diverged 80 million years ago with 48 changes, then the rate is 48 changes / 80 million years = 0.6 changes per million years. For two whale species with 6 changes, at the same rate, the time of divergence would be 6 changes / 0.6 changes per million years = 10 million years.

Whales and Pigs Diverged About 80 Million Years Ago