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Biology 11&12 Vocab

Chapter 11 & 12 Vocabulary

TermDefinition
gene pool collection of alleles found in all of the individuals of a population
allele frequency proportion of 1 allele, compared with all the alleles for that trait, in the gene pool
microevolution observable change in the allele frequencies of a population over a few generations
directional selection pathway of natural selection in which one uncommon phenotype is selected over 1 more common
stabilizing selection natural selection where intermediate phenotypes are selected over phenotypes of both extremes
disruptive selection natural selection where 2 opposite, but equally uncommon, phenotypes are selected over the most common one
gene flow physical movement of alleles from one population to another
genetic drift change in allele frequencies, due to chance alone, occurring most commonly in small populations
bottleneck effect genetic drift, results from an event that drastically reduces the size of a population
founder effect genetic drift, occurs after a small number of individuals colonize a new area
sexual selection certain traits enhance mating success , and are therefore passed on to offspring
reproductive isolation last stage in speciation where members of isolated populations are either no longer able to mate or no longer able to produce viable offspring
speciation evolution of 2 or more species from one ancestral species
behavioral isolation isolation between populations due to differences in courtship/mating behavior
geographic isolation isolation of populations die to the physical barriers between them
temporal isolation isolation between populations due to barriers related to time; such as differences in mating periods or time when individuals are most active
convergent evolution evolution towards similar characteristics in unrelated species, because of adaptations to similar environmental conditions
divergent evolution evolution of one or more closely related species into different species, because of adaptations to different environmetal conditions
coevolution process in which 2 or more species evolve in response to changes in each other
punctuated equilibrium the theory that speciation occurs suddenly and rapidly, followed by long periods of little evolutionary change
adaptive radiation 1 species evolves, gives rise to many descendant species that occupy different ecological niches
index fossils fossils of an organism that existed during only specific spans of geologic time across large geographic areas
cyanobacteria bacteria that can carry out photosynthesis
endosymbiosis ecological relationship in which one organism lives within the body of another
Created by: sydneyrs