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Ch 25

Terms in this set (19)

What are the natural biological barrier types?
Prezygotic, postzygotic
What are the different types of prezygotic barriers?
Habitat isolation, Temporal Isolation, Behavioral isolation, mechanical isolation, Gametic isolation
What are the different kinds of postzygotic barriers?
Reduced Hybrid Viability, Hybrid Breakdown,
What is Habitat isolation? Example?
Isolation due to different living environments; ie: a wood mouse never goes into the fields because it is bright and scary, and a field mouse never goes into the woods because it is dark and scary. They never meet, so they never mate.
Temporal Isolation
Sexually active at different times of the year
Behavioral Isolation
Courtship behavior related to reproduction: blue footed boobies have a courtship dance where they lift their feet up to show other blue footed boobies the color of their feet. This helps the females to distinguish between the blue and red footed males.
Mechanical isolation
Unsuccessful mating attempts; lovebugs where the male genetalia are the wrong "key" to the female's "lock" and they, mechanically, cannot physically reproduce
Gametic Isolation
ie: a lily and jasmine: wrong pollen: pollen tube won't grow to reach egg. This is a chemical reaction or signal that doesn't work. In mammals: If two mammals of the wrong species mate, there are actually chemicals in the female tract that can reject the sperm if the male is the "wrong" species.
Reduced Hybrid Viability
Embryo fails or is too weak; EX: two different species of salamanders that spawn a hybrid species, but the spawn is weak
Reduced hybrid fertility
Hybrdi survives but is sterile; ie: a horse and a donkey crossing to create a mule. Mule is strong but can't reproduce.
Hybrid breakdown
Hybrids are feeble or sterile
Speciation
increases diversity of life
Does microevolution make more species on its own?
Nope.
Punctuated equilibrium
a slow divergence as new species form, different variations of each species eventually evolve into a new species, but it is hard to tell when it actually becomes that new species definitively
Allopatric Speciation
With separation
Sympatric Speciation
Without separation
Which is more important for animals, allopatric or sympatric speciation?
Allopatric
Which type of speciation is more common in plants than in animals?
Sympatric
Two species of fish are in a lake with no barrier between them. In normal lighting, females always choose males of the same species. In lighting that does not allow the fishes' natural color to show, males were chosen at random. What type of selection is isolating these populations?
Behavioral sexual selection
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