Criteria of Calling Something Adaptive
If and only if a trait fulfills the following criteria will evolutionary biologists in general declare the trait an adaptation:
- The trait is a variation of an earlier form.
- The trait is heritable through the transmission of genes.
- The trait enhances reproductive success.
Adaptationists too agree with these rules, but their opponents maintain adaptationists are sometimes too eager to take an imaginative leap where the evidence is spotty or ambiguous.
Evolution cannot form perfect organisms for numerous reasons. Foremost is that some elements of an organism's physiology are subject to constraints that environmental pressure cannot alter.
Read more about this topic: Adaptationism
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