🐛 biology unit 7 evolution - allele frequencies and types of natural selection

flashcards from standard bio

5 ways Allele frequencies change

• Genetic Drift

• Sexual Selection

• Mutation

• Gene Flow

• Natural Selection

Genetic Drift

Random event that shrinks the gene pool (Ex. Diseases, fire)

Sexual Selection

Organisms choose their mates… Ex. (birds and cardinals)

Mutation

A change in DNA sequence

Gene Flow

Organisms moving in to or out of a population

Natural Selection

Strong survive, weak die.

In order for a species to change, what 4 things eed to be present in that population?

• Variation

• Environmental Pressures

• Change in population overtime

• Survival of the fittest

Directional Selection

Favors one extreme of the population

Stablizing Selection

Favors the average of the popluation

Disruptive Selection

Favors the opposite extremes of the population (NOT THE AVERAGE ONE) —> it can also lead to the development of two separate species