EvolutionMechanisms160-page16

EvolutionMechanisms160-page16 - Some examples of disruptive...

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Evolutionary Mechanisms - 16 Pesticide resistance Industrial Melanism Disruptive Selection In disruptive selection extremes are favored at the expense of intermediate forms of a trait, so that the frequencies of phenotypes at the extremes increase. A patchy environmental condition promotes disruptive selection Polymorphism is a common result of disruptive selection. Adaptive radiation is also a form of disruptive selection. It's possible to have polymorphism within a single habitat, if there are balances that favor more than one type. This is called balanced polymorphism, and the morphs that are adaptive are stable phenotypes.
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Unformatted text preview: Some examples of disruptive selection include the balanced polymorphism of sickle-cell anemia with malaria in Africa, populations of swallowtail butterflies that have different predators and the Galapagos and African finches with beaks suited to different food sources. African Finch Beaks Sickle-cell Anemia and Malaria Adaptive Radiation is a term that is often used when a single ancestral type eventually evolves into many similar species, each with specific differences, such as the Galapagos finches studied by Darwin and discussed previously....
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