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Speciation
The formation of a new species
Speciation- occurs in isolated populations
Geographic isolation leads to
reproductive isolation
Once the population is geographically isolated,
they adapt to their unique environment.
If they can no longer breed with the original
larger population they are considered a
separate species.
Ex: Galapagos Finches
1. Finches on the mainland migrate along the
coast
2. Blown off course, they landed on the
Galapagos Islands.
3. With lots of food an no predators their
population increased.
4. They spread to the other islands.
5. They adapted to the conditions on the
separate islands. (mutations caused different
bills)
6. The Finches became separate species once
they no longer reproduced with those whose
bill was different.
Ex: Death Valley Fish
1. Once a large lake filled the valley, with one
large fish population.
2. As the climate changed the lake dried up.
3. The fish became isolated in separate ponds
and adapted to local conditions.
4. They are now separate species.
Devil’s Hole
Pupfish
Salt Creek
Pupfish
Divergent evolution:
One species becomes many
Ex: Darwin’s
Finches
also called:
adaptive
radiation
Convergent evolution:
unrelated species become similar
because they adapt to the same habitat
placental mammal
white tail deer
vs
marsupial
kangaroo