Transcript Patterns of Evolution

Patterns of Evolution
Extinction
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More than 99% of all species that have
ever lived are now extinct
Reasons for extinction
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Competition for resources
Environmental change
Some species adapt and survive
(others do not)
Divergent Evolution
(Adaptive Radiation)
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Many diverse species evolved from a
similar, common ancestor
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Ex: Galapagos finches
Occurs due to natural selection, etc.
Adaptive Radiation
Convergent Evolution
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Unrelated organisms come to
resemble one another
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Ex: shark and dolphin
Coevolution
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Two or more species evolve in response to
changes in each other over time
Often occurs with organisms that are closely
connected with one another
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Symbiotic relationships!
Ex: Many flowering plants can reproduce only if the
shape, color and odor of their flowers to attract
specific pollinators
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Bees are attracted to certain types of plants and butterflies
are attracted to certain types of plants (some may be the
same, others may be different)
Punctuated Equilibrium
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Long stable periods are interrupted by
brief periods of more rapid change