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Peacocks have pretty fancy feathers. Why have they
evolved this way? Explain in terms of mate selection.
Alisa, Pratik, Yurie
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Sexual dimorphism
• Sexual dimorphism=
Evolution of
differences between
males and females
• In some species,
males have evolved
exaggerated traits
that advertise their
reproductive worth.
The colorful tail
feathers of peacocks
is a good example of
this.
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Secondary sexual characteristic=
Traits that are peculiar to one sex
or the other but are not part of the
actual reproductive organs.
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Why do male peacocks have
colorful tails?
• Extravagant traits provide an advantage in the competition
for mates.
• Extravagant traits get passed down from one generation to
the next, and through modification, the traits can become
more elaborate and attractive over time.
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Why do male peacocks have
colorful tails?
• The peacock's tail requires a great deal of energy to grow
and maintain, it reduces the bird's agility, and it increases
the animal’s visibility to predators. Yet it has evolved,
indicating that peacocks prioritize reproduction in terms
of survival
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Other Examples

Male deer fight with their antlers.

Blackbird and their singing to attract female
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Bibliography

http://www.slideshare.net/gurustip/e6-further-studies-ofbehaviour-hl

http://www.stanford.edu/group/stanfordbirds/text/essays/S
exual_Selection.html

http://www.thegreatdebate.org.uk/sexualselection.html