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Factors Affecting Fitness.notebook
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April 16, 2012
Factors Affecting Fitness
Natura
l Select
ionSelective PressuresEnvironmental
Change
Fecund
ity
Factors Affecting Fitness.notebook
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April 16, 2012
Fitness
The ability to both survive and reproduce
Some traits increase the fitness of an organism. This increases the chance the organism's genes/traits will be passed on to the next generation.
An individual's fitness is manifested through its phenotype
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Natural Selectionhttp://videos.howstuffworks.com/sciencechannel/29786100greatestdiscoveriesnaturalselectionvideo.htm
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Selective Pressure
Selective pressure is any factor that makes it difficult for an organism to survive
Under selection, individuals with advantageous or "adaptive" traits tend to be more successful than their peers reproductively—meaning they contribute more offspring to the succeeding generation than others do
This results in that adaptation being passed on to future generations
Selective pressures may result from any number of biotic or abiotic factors:
Ex: Disease, climatic changes, food availability, or predators
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Environmental ChangeA change or disturbance of the environment by natural ecological processes:
Global warmingVolcano eruptionFloodsEarthquakes
Environmental change is any change in an environment to which an organism must adapt.
Animals must adapt to environmental change. If not, they will eventually die out
Example: The ancestor of penguins closely resembled common birds. As the birds migrated north, they evolved many traits to help them survive the cold climate
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April 16, 2012
Fecundity
The potential reproductive capacity of an individual or population
Examples: sperm count, egg count, number of live offspring produced by an organism
Fecundity is under both genetic and environmental control, and is the major measure of fitness