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21 terms

AP Biology Chapter 23

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Sympatric
Speciation that occurs within one area - some factor other than geographical separation has prevented free interbreeding between members of the species.
Subspecies
populations of the same species that differ genetically because of adaptations to different living conditions
Gene pools
the combined genetic information of all the members of a particular population
Biological Species Concept
a species concept defining a species as a population or group thereof whose members potentially interbreed and produce fertile offspring
Reproductively isolated
pertaining to groups of organisms that, mainly because of genetic differences, are prevented from mating and producing offspring with members of other groups.
Reproductive Isolating Mechanisms
includes: temporal, behavioral, mechanical, and ecological
Prezygotic Isolating Mechanisms
Occurs before fertilization, prevents reproduction, prevents genotypes from entering gene pools
Postzygotic Isolating Mechanisms
anatomical or physiological difference between 2 species that prevents successful reproduction after mating has taken place
Pheromones
Chemicals secreted by animal species that influence the behavior of other animals of the same species
Temporal Isolation
form of reproductive isolation in which two populations reproduce at different times
Mechanical Isolation
morphological differences can prevent successful mating
Prevention of Gamete Fusion
Gametes of one species function poorly with the gametes of another species or within the reproductive tract of another species.
Allopatric
occurring in separate locations, describes populations that rarely interbreed because they are separated geographically
polyploidy
A chromosomal alteration in which the organism possesses more than two complete chromosome sets.
autopolyploidy
An organism having more than two sets of chromosomes, all of which were derived from the same species (self-fertilization).
allopolyploidy
Extra sets of chromosomes come from different species, arise from hybridization, new chromosomes have no homologues, can create new species if followed by autopolyploidy
adaptive radiation
process by which a single species or small group of species evolves into several different forms that live in different ways
character displacement
The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
gradualism
The theory that evolution occurs slowly but steadily
Punctuated equilibrium
pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
mass extinctions
mass destruction of most species