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22 Cards in this Set

  • Front
  • Back
Prezygotic barriers
prevent mating between species before formation of zygote
habitat isolation
two species live in same area occupy different habitats
temporal isolation
2 species breed @ different times
behavioral isolation
courtship rituals and behavorial signals are specie soecific
mechanical isolation
anatomical incompatiblity
gametic isolation
gametes fail to fuse, sperm cannot penetrate membrane of egg
postzygotic barriers
prevent from developing viable fertiel adult
reduced hybrid viability
zygote fails to survive embryonic development
reduced hybrid fertility
hybrid individual is sterile, inability to produce normal gametes in meiosis. horses and mule make sterile donkey.
hybrid breakdown
hybrids are viable and fertile, but offspring are feeble or sterile. grasses are weaker.
physical characteristics
how to identify species?
based on morphological, paleontological, ecological, phylogenetic, pluralistic. different definitions
the rold organisms play and resourves they use in specific environments. chain.
evolutionaray lineages, molecular sequences.
biological species concept
popuation who has potential to interbreed and produce viable, fertile offspring. reproductively compatible. hardest to determine.
allopatric speciation
geographic isolation interrupts gene flow. rivers change course, water level lowered, crack in mountain. different mutations and pressures for selection arise.
sympatric speciation
speciation in geographically overlapping populations.
extra set of chromosomes, mutations from meosis. autopolyplod maybe sterile but can reproduce asexually. wheat, grass, tobacco, put in extra, desired chromosomes.
evolution of reproductive barriers example
starch and maltose flies cannot interbreed. breed with same kind.
adaptive radiation
diversely adapted species from common ancestor when introduced to new environment and challenges. galapogos and hawaiian islands.
punctuated equilibrium
leaves no fossil record. species appear suddenly
phyletic gradualism
speciation occurs gradually. can trace divergence points.