Speciation
name:__________________________
Species: A group of organisms capable of interbreeding
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1)______________________________________________________________________
2)______________________________________________________________________
Two Reproductive Isolation Mechanisms:
1) Prezygotic Isolating Mechanisms:_______________________________________________________
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Eg._____________________________________________________________________
2)Postzygotic Reproductive Isolation:_____________________________________________________
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Eg.1)___________________________________________________________________________________________
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Eg.2)___________________________________________________________________________________________
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Causes of Reproductive Isolation Mechanisms:
Prezygotic
Isolation
Habitat
Isolation
Temporal
Isolation
Behavioral
Isolation
Mechanical
Isolation
Definition
Example
Postzygotic
Isolation
Definition
Example
Gamete
Isolation
Zygote
Isolation
Hybrid
Sterility
F2 Fitness
Process of Speciation
Speciation:____________________________________________________________________________________
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Allopatric Speciation:________________________________________________________________________
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Sympatric Speciation:________________________________________________________________________
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Eg._____________________________________________________________________________________________
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Pace of Speciation:
2 Hypothesis that address the pace of speciation
1) Phyletic Gradualism Model:
2) Punctuated Equilibrium:
How do Both Models Explain the lack of Transition Fossils in the Fossil Record?
Phyletic Gradualism:_________________________________________________________________________
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Punctuated Equilibrium:____________________________________________________________________
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Questions:
1) Compare and Contrast the way gradualism and punctuated equilibrium happen.
2) How do punctuated equilibrium and gradualism explain the lack of transition
fossils in the fossil record.
3) Compare and contrast between allopatric and sympatric speciation.
5) Which type of reproductive isolation is depicted in the following
Example of Reproductive Isolation
1) An inlet is closed and the salt water
slowly turns into freshwater. The
population of crabs slowly adapts to
freshwater. They can no longer travel over
to the saltwater population to interbreed.
2) A liger is a cross between a lion and
tiger. Ligers are sterile animals.
3) A flowering plant is crossed with a
different species to form a reproductive
hybrid. When the reproductive hybrids are
crossed together they form a sterile plant.
4) A purple ringed topsnail spawns at the
same time as another species of topsnail.
Although the eggs are fertilized and the
embryo starts to develop it dies shortly
after fertilization.
5) One population of frogs have a low pitch
breeding call. A mutation in one spawn
produces offspring with a high pitch call.
This call is not recognized by the original
population creating two isolated
populations
6) Several species of coral mass spawn in
one night. One species produces a thick
shelled egg. The sperm of another species
tries to enter the egg but cannot pass
through the egg’s shell.
7) Rednecked duck eggs were placed in a
canvas back ducks nest. The rednecked
ducks learned the mating dance of the
canvas back not his own species. Although
they performed the canvas mating dance
well they were not able to impress the
rednecked females.
Prezygotic or
Postzygotic
Isolation
Type of Isolation
Prezygotic or
Postzygotic Isolation