24 terms

Ch 13: How Populations Evolve

natural selection
process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are individuals with other characteristics
a group of individuals of the same species living in the same place at the same time, changes over generations
evolutionary adaptation
a population's increase in the frequency of traits suited to the environment
a change in the genetic composition of a population over time
remains of organisms that lived in the past
the study of the geographic distribution of species
fossil record
ordered sequence of fossils as they appear in rock layers
comparative anatomy
comparison of body structures between difference species
similar structures due to common ancestry
vestigial structures
remnants of features that served important functions in an organism's ancestors and not have no functions
modern synthesis
genetics with evolutionary biology
gene pool
the total collection of alleles in a population at any one time
Hardy-Weinberg equilibrium
if met the population is NOT evolving
generation to generation change in a population's frequencies of alleles
genetic drift
change in the gene pool of a small population due to chance
bottleneck effect
reduced population size, decreases genetic variability, and adaptability
founder effect
when a few individuals colonize an isolated habitat
gene flow
genetic exchange with another population which may lead to a gain or loss of alleles and decreases genetic differences between populations
relative fitness
the contribution an individual makes to the gene pool of the next generation
directional selection
shifts the overall makeup of a population by selecting in favor of one extreme phenotype
disruptive selection
leads to a balance between two or more contrasting phenotypes
stabilizing selection
favors intermediate phenotypes, occurs in stable populations
sexual selection
individuals with certain traits are more likely than others to obtain mates
sexual dimorphism
distinction in appearance between males and females not associated with reproduction or survival