>I'm not a YEC, but I am a skeptic of evolution as creative force in nature,
>if evolution is defined as _natural selection_. One of the fundamental
>characteristics of natural selection is that it cannot foresee the future.
>
>You wrote about the article in _Nature_ "They're obviously not flight
>feathers, but they are a possible preadaptation ready for transformation in
>gliding arboreal dinos or leaping cursorial dinos."
>
>If natural selection cannot operate beyond adaptation to the immediate
>environment how can filaments be foreseen as later bases for feathers?
>Unless they have some immediate adaptive value, the genes expressing them
>would be eliminated from the gene pool.
Preadaptations can be recognized only in retrospect. They are simply
adaptations at the time, and their future utility cannot be anticipated by
the organism. The examination of the fossil record seems to indicate that
the initial appearance of a novel character is associated with a function
unrelated, or only tangentially related, to its eventual function. In this
case, these structures certainly did not have a flight function, but likely
did have some thermoregulatory purpose. Once they exist, they are then
subject to other selective forces that may co-opt them for other purposes.
Keith
Keith B. Miller
Department of Geology
Kansas State University
Manhattan, KS 66506
kbmill@ksu.ksu.edu
http://www-personal.ksu.edu/~kbmill/