Semester 2 Final Exam Vocab Review Set 3: Evolution Mrs. K

vestigial structure

structure that is inherited from ancestors but has lost much or all of its original function

comparative embryology

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

homologous structure

body part that is similar in structure on different organisms but performs different functions

natural selection

A natural process resulting in the evolution of organisms best adapted to the environment.

Evolution

Change over time

Fitness

Ability of an organism to survive and reproduce in its environment

Speciation

the formation of new and distinct species in the course of evolution.

analogous structures

structures that do not have a common evolutionary origin but are similar in function

Fossil

The preserved remains or traces of an organism that lived in the past. Also evidence of evolution.

allele frequency

Number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene

Adaptation

inherited characteristic that increases an organism's chance of survival

directional selection

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

stabilizing selection

natural selection that favors average individuals in a population; results in a decline in population variation

disruptive selection

favors individuals at both extremes of the phenotypic range

geographic isolation

form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water

temporal isolation

form of reproductive isolation in which two populations reproduce at different times

hybrid infertility

hybrid offspring are sterile or have low fertility

behavioral isolation

isolation between populations due to differences in courtship or mating behavior

Mechenical Isolation

Mating occurs, but structurally doesn't fit