Reference no: EM132603834

As is true for many issues in biology, scientists have proposed a number of competing definitions for adaptation (see Harvey and Pagel 1991, Lauder et al. 1993, Reeve and Sherman 1993). For some, the term must be reserved for a characteristic that provides "current utility to the organism and [has] been generated historically through the action of natural selection for its current biological role." What do you think current utility means? If a trait originated for function X and later took on a different, but still adaptive, biological role Y, does that mean it is not an adaptation? Track down the evolutionary history of the flight feathers of modern birds (see Prum and Brush 2002). Where did these feathers come from, and what function did their predecessor feathers exhibit? If you go back far enough in time, will the ancestral form of any current trait have the same function that it does now?