Heredity, Natural Selection, and Evolution

Natural Selection

What are the different types of natural selection?

Natural selection can cause a population to change in several ways. For example, natural selection can cause a trait to change in one direction only, such as when individuals within a population grow taller with each generation, and this is known as directional selection. Diversifying selection can cause the loss of individuals in the midrange of a trait. For example, if a certain prey species ranges in color from very dark to very light, those individuals in the midcolor range may not be able to hide from predators. The midcolor prey will then be selectively removed from the population, leaving the population with only two forms, the very dark and the very light. In stabilizing selection, those at either end of the range are removed more often, creating selection pressure for the midrange. Selection can also work on traits important to sexual reproduction; this is known as sexual selection.


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