Of course, the natural world is full of adaptations but it is also full of traits that are not adaptations, and recognizing this is important.
Re "Depression Defies the Rush to Find an Evolutionary Upside" (Essay, Jan . 17: Asking if diseases are or are not adaptations is the most elementary mistake in evolutionary medicine.
However, before we examine traits that are not adaptations, it will be useful to specifically define what an adaptation actually is and how we can determine whether or not a trait qualifies as an adaptation.
The four Shakespeare films on BBC1 are not adaptations, or new versions, but 'modern reinterpretations' of Shakespeare plays for television by contemporary playwrights and directors.
"South Pacific" has its merits, but the Minnelli films exist in another dimension: these are not adaptations but original works that embrace all that is unique about the motion picture medium.
Some traits are present and very beneficial, and yet are not the result of natural selection and hence are not adaptations.
A sea turtles forelegs are useful for digging in the sand to bury eggs but they are not adaptations for nest building (Sober 2000, 85).
Ontogenetic adaptations, including any behavior we learn in our lifetimes, can be adaptive to the extent that an organism benefits from them but they are not adaptations in the relevant sense.
The view expressed here that all (or even most) interesting properties of the language faculty are not adaptations conflicts with the basic explanatory strategy of evolutionary psychology found in the neo-Darwinian Essentialist views of Pinker and Bloom.
Note that lag1 is not adaptation by mutation, but rather acclimatization of the cell physiology to new conditions.
