24.3 The Pace of Speciation

24.3 The Pace of Speciation

• Change is gradual over a long time period.

• Some pea aphids prefer red clover, while others prefer alfalfa.
• The two populations may be in the same situation.

• One type of sexual selection is mate choice.

• Male coloration rapid evolutionary change is subject to female choice in African cichlids.
• Sexual vertical lines are periods of equilibrium in which change selection appears to have followed a minimal diversifying mechanism.

• The concepts of gradualism and phenotypic characteristics may change quickly.

• The pace of evolution has not been constant throughout the history of life on Earth.

• The idea is that the pace of evolution is more sporadic.