Multiplication of Species
p. 112-115
Speciation
? A branch point on the evolutionary tree means ________________________________________
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? According to Darwin, the __________________________________________________________ between geographically separated populations provides the material for new species to develop.
? Biological species concept
? 1) ______________________________________________________________________
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? 2) ______________________________________________________________________
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? 3) ______________________________________________________________________
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Reproductive Barriers
? ______________________________________________________________________________
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? ________________________________________ isolation is the most common.
? Diverging populations must be _________________________________ separated from each other for long periods of time (10,000-100,000 y)
? ____________________________ Isolation
? ____________________________ Isolation
Allopatric Speciation
? Allopatric populations occupy ______________________________________________________
? They don’t interbreed because they can’t get to each other, but if they could, they would.
? Allopatric speciation results from ___________________________________________________
_______________________________________ between geographically separated populations.
? Begins when a species splits into 2 or more geographically separated populations.
? ___________________________ speciation – climatic or geological changes fragment a species’ habitat
? Does not induce genetic change by ____________________________________, or by ___________________________________________ to an unfamiliar area
? May fragment several different species simultaneously
? Founder event – __________________________________________________________
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Hybridization
? Mating between ____________________________________ populations
? By studying the genetics of hybrid populations, we can _________________________________
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Sibling Species
? Different species that are ______________________________________________ in organismal appearance
? Have premating barriers
? ____________________________________________________
? ____________________________________________________
Nonallopatric Speciation
? Sympatric speciation
? Individuals become specialized for occupying ________________________ components of the environment
? By having specific habitats in a single geographic area, populations achieve sufficient ________________________________ and ____________________________________ separation to evolve reproductive barriers
Adaptive Radiation
? Production of ecologically diverse species from a ______________________________________
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? Galápagos finches (13 sp.)
? Closely related, but each species differs in _______________________________
_____________ and in ______________________________________________