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Warm Up 7
3/11
What is genetic equilibrium?
What does the Hardy Weinberg principle state?
Under what 5 conditions does Hardy Weinberg hold true for NO evolution to occur?
Can there be evolution without natural selection?
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2. Hardy Weinberg Principle: states that allele frequencies in a population will remain constant unless one or more factors cause those frequencies to change
Genetic equilibrium- situation in which allele frequencies remain constant
Must be random mating
Population must be very large
No movement into or out of the population
No mutations
No natural selection

3. 16-3 The Process of Speciation
Photo credit: ©MURRAY, PATTI/Animals Animals Enterprises
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4. 16-3 The Process of Speciation
Natural selection and chance events can change the relative frequencies of alleles in a population and lead to speciation.
-Speciation is the formation of new species.
-Species is a group of organisms that breed with one another and produce fertile offspring.
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5. True or False
Individuals in different species can have the same gene pool.

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Isolating Mechanisms
False
What factors are involved in the formation of new species?
The gene pools of two populations must become separated for them to become new species.
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Isolating Mechanisms
Isolating Mechanisms
As new species evolve, populations become reproductively isolated from each other.
reproductive isolation- members of two populations cannot interbreed and produce fertile offspring
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Reproductive Isolation
1. Behavioral isolation
2. Geographic isolation
3. Temporal isolation
Steps to Speciation
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Isolating Mechanisms
1. Behavioral Isolation 
Behavioral isolation- two populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior.
Eastern Meadowlark
And
Western Meadowlark
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Isolating Mechanisms
2. Geographic Isolation 
Geographic isolation- two populations are separated by geographic barriers (rivers or mountains).
Kaibab
Abert
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Isolating Mechanisms
3. Temporal Isolation  
Temporal isolation- when 2 or more species reproduce at different times.
Eastern spotted mates in Spring
Western spotted mates in Fall
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12. What are the 3 types of reproductive isolation?

13. Speciation in Darwin's Finches
STEPS OF SPECIATION
founding of a new population
geographic isolation
changes in new population's gene pool
reproductive isolation
ecological competition
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14. Speciation in Darwin's Finches
1. Founders Arrive 
A few finches—species A—travel from South America to one of the Galápagos Islands.
Speciation in the Galápagos finches occurred by founding of new populations, geographic isolation, gene pool changes, reproductive isolation, and ecological competition. Small groups of finches moved from one island to another, became reproductively isolated, and evolved into new species.
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15. Speciation in Darwin's Finches
2. Geographic Isolation
Some birds from species A cross to a second island.
Birds are separated by water.
Speciation in the Galápagos finches occurred by founding of new populations, geographic isolation, gene pool changes, reproductive isolation, and ecological competition. Small groups of finches moved from one island to another, became reproductively isolated, and evolved into new species.
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16. Speciation in Darwin's Finches
3. Changes in the Gene Pool
Seed sizes on the second island favor birds with large beaks.
The population on the second island evolves into population B, with larger beaks.
Speciation in the Galápagos finches occurred by founding of new populations, geographic isolation, gene pool changes, reproductive isolation, and ecological competition. Small groups of finches moved from one island to another, became reproductively isolated, and evolved into new species.
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17. Speciation in Darwin's Finches
4. Reproductive Isolation
If population B birds cross back to the first island, they will not mate with birds from population A.
Populations A and B are separate species.
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18. 5. Ecological Competition
As species A & B live together in same environment, they compete with each other for available seeds
Species evolve in a way that increases the differences between them

19. 6. Continued Evolution Process repeats itself
13 different finch species today

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16-3
When two species do not reproduce because of differences in mating rituals, the situation is referred to as
temporal isolation.
geographic isolation.
behavioral isolation.
reproductive isolation.
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16-3
The most important factor involved in the evolution of the Kaibab and Abert squirrels of the American Southwest appears to be
temporal isolation.
geographic isolation.
behavioral isolation.
different food sources.
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16-3
All of the following played a role in speciation of Galápagos finches EXCEPT
no changes in the gene pool.
separation of populations.
reproductive isolation.
natural selection.
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16-3
List the steps of speciation.
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24. Testing Natural Selection in Nature
Studies showing natural selection in action involve descendants of the finches that Darwin observed in the Galápagos Islands.
The finches Darwin saw were different, but he hypothesized that they had descended from a common ancestor.
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25. Testing Natural Selection in Nature
Detailed genetic studies have shown that these finches evolved from a species with a more-or-less general-purpose beak. 
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26. Testing Natural Selection in Nature
Detailed genetic studies have shown that these finches evolved from a species with a more-or-less general-purpose beak. 
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27. Testing Natural Selection in Nature
Peter and Rosemary Grant tested Darwin’s hypothesis, which relied on two testable assumptions:
For beak size and shape to evolve, there must be enough heritable variation in those traits to provide raw material for natural selection.
Differences in beak size and shape must produce differences in fitness, causing natural selection to occur.
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28. Testing Natural Selection in Nature
When food was scarce, individuals with large beaks were more likely to survive.
This graph shows the survival rate of one species of ground-feeding finches, the medium ground finch. 
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