Section 3
Adaptive Evolution
Book
Version 32
By Boundless
By Boundless
Boundless Biology
Biology
by Boundless
5 concepts
![Thumbnail](../../../../../../figures.boundless-cdn.com/27472/square/evolution_sm.jpg)
Natural Selection and Adaptive Evolution
Natural selection drives adaptive evolution by selecting for and increasing the occurrence of beneficial traits in a population.
![Thumbnail](../../../../../../figures.boundless-cdn.com/27333/square/directional selection.jpg)
Stabilizing, Directional, and Diversifying Selection
Stabilizing, directional, and diversifying selection either decrease, shift, or increase the genetic variance of a population.
![Thumbnail](../../../../../../figures.boundless-cdn.com/19047/square/figure-19-03-02.jpeg)
Frequency-Dependent Selection
In frequency-dependent selection, phenotypes that are either common or rare are favored through natural selection.
![Thumbnail](../../../../../../figures.boundless-cdn.com/27474/square/ribbon-tailed_astrapia.jpg)
Sexual Selection
Sexual selection, the selection pressure on males and females to obtain matings, can result in traits designed to maximize sexual success.
![Thumbnail](../../../../../../figures.boundless-cdn.com/20529/square/rphism-in-cepaea-nemoralis.jpeg)
No Perfect Organism
Natural selection cannot create novel, perfect species because it only selects on existing variations in a population.