Biological Evolution and Speciation

Flashcards covering key vocabulary and concepts related to biological evolution and speciation.

Natural Selection

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

Directional Selection

A form of natural selection that favors one extreme phenotype over the mean or other extreme.

Stabilizing Selection

Natural selection that favors intermediate variants by acting against extreme phenotypes.

Disruptive Selection

A form of natural selection that favors individuals at both extremes of the phenotypic range.

Speciation

The process by which new and distinct species arise.

Prezygotic Barriers

Features that prevent mating or fertilization between species.

Geographical Isolation

Separation of populations due to physical barriers.

Temporal Isolation

Species breed at different times.

Behavioral Isolation

Differences in mating behaviors that prevent species from interbreeding.

Mechanical Isolation

Physical differences prevent successful mating between species.

Gametical Isolation

Sperm of one species may not be able to fertilize eggs of another species.

Dimorphism

The occurrence of two distinct forms of a species.

Parapatric Speciation

Speciation occurring when populations are partially separated and exposure to different selective pressures leads to divergence.

Sympatric Speciation

Speciation that occurs without physical separation of members of the same species.