[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: silly question
From: Gary Vatnsdal <email@example.com>
> But feathers are another thing. There are
> some coasting mammals like flying squarrels, and some flying mammals like
> the bat and some flying dinosaurs like archaeopteryx. But what strange force
> of nature started the development of these feathers?
A good question, but a simple one to answer.
Feathers originally evolved for *warmth*. That is, the primal,
ancestral, function of feathers was (and still is) insulation
(an important, nay vital, function in small endotherms).
The shift to use in flight was secondary - and only the tail
and wing feathers were significantly altered by that shift.
This sort of shift of a structure's use after it has evolved is
a common theme in evolution.
Now, just exactly what prompted the enlargement of the arm
feathers of the proto-bird into something large enough to be
at least a parachute is still controversial, and very unclear.
> Is there fossil
> record of this happening? Were Dino birds well developed when the K-T
> event took place?
Birds were long established at the K-T boundary. Archaeopteryx,
the oldest established bird, is from the Late Jurassic, about
70 million years prior to the K-T boundary. There is a modest,
if very fragmentary, fossil record of birds from the Cretaceous,
showing a substantial variety of birds by the end of the Cretaceous.
[Even some relatively specialized forms, like ducks and cormorants,
had already evolved by then].
The peace of God be with you.