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27 Cards in this Set

  • Front
  • Back
biological species concept
able to breed with one another to produce fertile offspring
reproductive isolating mechanisms
prevent interbreeding b/t 2 diffrent species whose ranges overlap. gene flow is prevented
prezygotic barriers
reproductive isolating mechanisms that prevent fertilization
5 types of prezygotic barriers
temporal isolation
similar species mate @ diffrent times
habitat isolation
similar species mate in diffrent habitats
behavioral isolation
similar species have diffrent courtship behaviors
gametic isolation
gametes in similar species are chemically incompatible
postzygotic barriers
fertilization occurs however these barriers increase the likelihood of reproductive failure
3 types of postzygotic barriers
hybrid inviability
hybrid sterility
hybrid breakdown
hybrid inviability
interspecific hybrid dies at the embryonic stage.

genes from parents don't interact properly for normal development
hybrid sterility
interspecific hybrid survives but is sterile.

2 causes:
(1) hybrid animals may exhibit courtship incompatible with those of parental species
(2) gametes are abnormal in meiosis (can't pair properly in prophase)
hybrid breakdown
offspring of interspecific hybrid are unable to reproduce
evolution of new species
2 ways of speciation occuring
allopatrick and sympatrick
allopatric speciation
1 pop becomes geographically seperated and evolves by natural selection and/or genetic drift
sympatric speciation
new species evolves within the same geographical area. this occurs when reproductive isolating mechanisms evolve at the start of speciation
contains multiple sets of chromosomes from 2 or more species
sexual reprodction b/t individuals from closely related species
can self-fertilize or find likes of themselves
2 models of evolutionary rate
punctuated equilibrium
punctuated equilibrium
suggests that fossil record actually reflects evolution

long periods of stasis (little or no evolutionary change) are punctuated or interrupted by short periods of rapid speciation, triggered by environment.

speciation proceeds in spurts
evolution proceeds continously over long periods. rarely observed in fossil record b/c record is incomplete
large-scale phenotypic changes in populations
adaptive radiation
evolutionary diversification. "divergent evolution"
adaptive zones
ecological areas on the islands that were not already occupied by other pop. which brings about competition
last member of species dies. frees adaptive zones.