speciation Flashcards
how does a new species form
1-geographic isolation
2-divergent evolution - 1 species evolves into two extremes
3- convergent evolution- species not closely related evolve similar traits (like dolphins and fish both have fins)
4-reproduction isolation- inability to exchange genes among a species
5- adaptive radiation-divergent evolution and adaptations of species to differerent roles and new habitats
how does reproductive isolation work in animals
the sperm cant fertilize the egg (the eg has aprotective layer the sperm has to break down first before attaching and it needs special enzymes to work. so diff species may not be able to break down the protective layer)
inability to fertilize can lead to
a prezygotic
what does prezygotic mean
no baby is made
what is a postzygotic
an unhelathy, sterile baby is made
how does reproductive isolation work in plants
pollenation times are different
what is temporal reproductive isolation
mating season is different (animals in heat/ plants in pollen season)
what is geographic reproductive isolation
geographic isolated
what is allopatric speciation
when a popualtion forms a new species while geographically isolated from parent population
what is th most common speciation?
allopatric speciation
what is sympatric speciation
a small population becomes a new species while still in th parent population
(selective breeding)
gradualism
the tempo of speciation is steady change
puntuated equilibrium
the tempo of speciation is puntuated by short events of rapid evolution
