Natural Selection Flashcards

Directional Selection

Selection that favors one extreme phenotype over the mean or other extremes.

Stabilizing Selection

Selection that favors intermediate phenotypes and acts against extreme phenotypes.

Disruptive Selection

Selection that favors extreme phenotypes and selects against intermediate phenotypes.

Speciation

The formation of new and distinct species through evolutionary processes.

Gradualism

A model of speciation that occurs through slow and gradual changes over time.

Punctuated Equilibrium

A model of speciation characterized by long periods of stability interrupted by brief periods of rapid change.

Geographic Isolation

The separation of populations due to physical barriers which can lead to speciation.

Morphological Changes

Changes in the physical form or structure of organisms.

Divergent Evolution

Evolution where related species become more and more different due to adaptation to different environments.

Convergent Evolution

Evolution where unrelated species evolve similar traits due to similar environmental pressures.

Coevolution

The process by which two or more species evolve in response to each other.

Homologous Structures

Anatomical features in different species that share a common ancestor.

Analogous Structures

Anatomical features that serve similar functions but did not arise from a common ancestor.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Hardy-Weinberg Principle

A principle that describes a population that is not evolving; allele and genotype frequencies remain constant.

Fertile Offspring

Offspring that can themselves reproduce and continue the species.

Natural Habitat

The natural environment in which a species lives and evolves.

Fitness

An organism's ability to survive and reproduce in its environment.

Selective Pressure

Environmental factors that contribute to natural selection by favoring certain traits.