Evolution Vocabulary

Evolution

Gradual change of allele frequencies in a population

Natural selection

Process whereby organisms with favorable variations survive and produce more offspring than organisms with less favorable variations

Homologous structures

structures found in different kinds of organisms that have the same basic arrangement of parts and a similar pattern of embryological development

Analogous structures

structures found in different types of organisms that are similar in function or outward appearance but dissimilar in basic structure or embryological development

Vestigial structures

non-functional structures in an organism that are a remnant of structures that were functional in an ancestral form of the organism

Embryology

the study of the similarities and differences in the embryos of different species

Biogeography

Study of past and present distribution of organisms

Fitness

ability to survive and create offspring

Adaptation

Inherited traits that enhance survival and reproduction in certain environments

Gene pool

All the genes, including all the different alleles for each gene, that are present in a population at any one time

Directional selection

occurs when natural selection favors one of the extreme variations of a trait

Stabilizing selection

Occurs when natural selection that favors intermediate variations by acting against the extreme ones

Disruptive selection

favors individuals at both extremes of the phenotypic variations

Variation

Any difference in phenotypes between individuals of the same species.

Microevolution

evolutionary change within a species or small group of organisms, especially over a short period.

Macroevolution

large-scale evolutionary changes that take place over long periods of time

Speciation

Formation of new species as a result of macroevolution

gene flow

movement of alleles from one population to another