bio lecture ch 22 (copy)

Mutation

Introduces new variants to a population; alone, it does not lead to evolutionary change without other forces.

Genetic Drift

Random changes in allele frequencies within a population.

Migration (Gene Flow)

Movement of individuals between populations affecting genetic diversity.

Natural Selection

The process through which certain traits become more common in a population due to advantageous characteristics.

Directional Selection

A form of natural selection that favors one extreme phenotype over others, leading to a shift in a population's traits.

Stabilizing Selection

A form of natural selection that favors intermediate variants, reducing variation and maintaining the status quo.

Disruptive Selection

A form of natural selection that favors extreme phenotypes over intermediate ones, potentially leading to speciation.

Intrasexual Selection

Competition among individuals of the same sex for mating opportunities.

Intersexual Selection

Mate choice based on preferred traits, often seen in females.

Speciation

The process leading to the formation of new species through evolutionary forces creating sufficient differences.

Morphological Species Concept

A concept based on physical characteristics; used by paleontologists when reproductive behavior isn't observable.

Zebra Finch Study

An example of intersexual selection where female preference for males with red leg bands illustrates mate choice dynamics.

Ring Species

A phenomenon illustrating gradual changes across populations in a circular geographic pattern where adjacent populations can interbreed but extremes cannot.

Clines

Gradients of traits shown across different populations, driven by selection, drift, and gene flow.

Prezygotic Isolation

Mechanisms preventing mating or fertilization, which include behavioral, temporal, and mechanical isolation.

Postzygotic Isolation

Occurs after fertilization and includes hybrid inviability or sterility.

Endangered Species Act

A significant law for biodiversity conservation aimed at protecting threatened species.