macroevolution + speciation

macroevolution looks at these 2 processes

speciation and extinction

what defines a species?

cannot breed with each other

reproductive isolation maintains…

differences between groups

biological species concept is like the major…

definition of species

biological species concept states…

a species is a group that doesnt interbreed with other groups

zygote

fertilized egg

reproductive isolating mechanisms do what to gene flow?

decrease

(strong) enough reproductive isolating mechanisms lead to new...

species

2 main types of isolating mechanisms

prezygotic, postzygotic

2 categories of prezygotic isolation mechanisms

premating, mating

3 types of premating isolation

temporal, habitat, behavioral

habitat isolation

different habitat prevents encounters/mating

temporal isolation

species reproduce at different times/seasons

behavioral isolation

females of one species dont recognize males of another species as potential mates

2 types of mating isolation

mechanical, gamete

mechanical isolation

genitalia between species are incompatible

gamete isolation

sperm cannot reach or fertilize egg

3 types of postzygotic isolation

zygote dies, hybrid sterility, f2 fitness

hybrid sterility

hybrid organism survives but cant reproduce

f2 fitness

hybrid can reproduce but has lower fitness

gene flow tends to make species more…

similar

will gene flow prevent or assist speciation?

prevent

allopatric speciation

divergence between geographically isolated populations

allopatric speciation is the most _____ type of speciation

common

what can cause divergence?

natural selection, genetic drift

divergence generates…

mating isolation

reinforcement

the two separate populations come back together

there is a chance for ______ in reinforcement

interbreeding

does reinforcement always happen?

no

if interbreeding happens during reinforcement, what happens to hybrids?

they may not get chosen

_______ mating isolation selects for ________ mating isolation

postzygotic, prezygotic

hybrid zone

where interbreeding occurs

3 possible outcomes when closely related species meet in hybrid zone

reinforcement, fusion, stability

fusion

interbreeding merges the two populations back together

stability

different species still persist

archipelago

group of islands

archipelagoes often _____ populations, so support rapid _______

isolate, speciation

prokaryotes originated around how many years ago?

4 billion

eukaryotes originated around how many years ago?

2 billion