Midterm 2 - Chapter 3, 20, 40

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24 Mar 2012
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3.2 selections
occurs when some force or phenomenon affects the survival of individual
organisms
Occurs when a large population of individuals is exposed to a lethal factor
and only resistant individuals survive and reproduce
Key factors behind selection are a selective force (pressure) and the
capacity for explosive population grown
Selection is the major force responsible for evolution and biodiversity
40.11) sexual selection
Sexual dimorphism: one gender is larger or more colourful than the other
can be an outcome of sexual selection
Why do females choose males with exaggerated structures?
Because a males large size, bright feathers or large horns indicate that he is
particularly healthy
He can harvest resources efficiently or simply that he has managed to
survive to an advanced age.
The features are signals of male quality and if they reflect a males
genetic makeup he is likely to fertilize a females eggs with sperm
containing successful alleles.
20.8) Evolutionary development biology
Asks how evolutionary changes in genes regulating embryonic development can
lead to changes in body shape and from.
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