Patterns of Selection Flashcards

Study Notes

Patterns of Selection

Three main types of patterns of selection: Stabilizing Selection, Directional Selection, and Disruptive Selection.

Stabilizing Selection

Selection against individuals at the extremes of a characteristic, favoring the average individuals.
Results in reduced variation within the population, as extremes are less likely to survive.

Example of Stabilizing Selection

Brown mice are favored over white and black mice.
White and black mice are more easily spotted by predators, leading to their decreased survival.
Over time, the population predominantly consists of brown mice.

Directional Selection

Occurs when one extreme of a characteristic is favored in response to environmental changes.
Leads to a shift in the population's characteristics over generations.

Example of Directional Selection

Insecticide use results in the selection of resistant individuals.
Initially, only a few resistant individuals exist, but over time, the population predominantly consists of resistant traits due to survival advantages.

Disruptive Selection

Selection favors both extremes of a characteristic while the intermediate is selected against.
This type of selection can lead to speciation by promoting diversity within a population.

Example of Disruptive Selection

In insects inhabiting plants with either dark green or light green leaves, medium green insects are more vulnerable to predation.
Medium green insects are more likely to be eaten, resulting in a population skewed towards the extremes of coloration (dark green or light green).

Description

Explore the three main types of patterns of selection: Stabilizing selection, Directional selection, and Disruptive selection. This set of flashcards will help you understand each type and provide examples to enhance your learning experience.