Download Speciation Notes - Northwest ISD Moodle

Speciation Notes
1. Speciation
Speciation is..
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So…what is a species?
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 Being reproductively compatible is a key component
2. How do you get a new Species?
Geographic isolation:
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Ecological isolation
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Temporal “time” isolation
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Behavioral isolation
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o
o
o
identifies members of species
attract mates of same species
courtship rituals, mating calls
Mechanical isolation
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3. Other forms of Speciation
Remember: _____________________: Change to gene pool of a population that takes place strictly by random
chance
Two major results can stem from Genetic Drift:
Bottleneck Effect
Founder Effect
4. Bottleneck Effect
Population bottleneck occur when a population’s size is _______________________ for at least one
generation.
Results in reduced _____________________________________________
Example:
Northern Elephant Seals- due excessive hunting in the late 1890’s, the population bottleneck leaving fewer than 20
seals left in the world. Today there are more than 30,000 of these seals BUT still have reduced genetic variation
5. Founder Effect
A founder effect occurs when a new colony is started by a few members of the original population.
This small population size means that the colony may have:
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Example #2- Birds: Which colonies would could result from the Founder Effect?