ABSTRACT
When addressing the specific ways in which an organism’s evolutionary past can influence its contemporary nature, biological scientists often invoke the concept of adaptation (Amundson, 1996; W. J. Bock, 1980). Although adaptations can be defined in many ways, most biologists consider adaptations to be those attributes of an organism that show evidence of “special design” for the purpose of increasing fitness (M. R. Rose & Lauder, 1996; Williams, 1966). Evidence of special design can come from showing that an attribute is extremely efficient, subtly complex, incredibly specialized, and emerges reliably in all members of a species. Evidence of functionality can come from showing that an attribute enhances fitness and leads to differential reproductive success relative to same-sex conspecifics (or at least would have done so in the ancestral past; see Crawford, 1998).
