Re: Origin of feathers

["Tony Canning" <tonyc@foe.co.uk>]

On Apr 8, 10:44pm, Thom Quinn wrote:

> Thom:
> Hey, no one is suggesting that organisms are "wishing" these into
> existence. This is not a neo-larmarkian explanation. Pre-feathers
> obviously came about from some kind of mutation to the dermal surface,
> either via scales, skin, or a new kind of structure. This example is
> totally hypothetical: The red skinned dino does well at attracting
> mates. A mutation occurs. The red skinned dino with the sudden new
> ridges does much better, at least with some mates that like the novel
> "show" of ridges added.
> The "behavior evolve first" hypothesis is one of the main tenets of
> modern zoology. And it is not always untestable! In this case, yes, I
> agree, it is hard to test.
>-- End of excerpt from Thom Quinn

It has been tested with frogs - females (I forget which species) were
found to respond more strongly to artificially constructed male vocal
calls than to those of their own species - the artificial calls were
based on natural calls with added complexity.  Although neither these
frogs nor their ancestors had ever encountered this call, it was immediately
more sucessful at attracting females.  This suggests that sexual selection
may favour elaboration of display structures/behaviour,
maybe accounting for peacock tail-type phenomena.

Therefore, if therapods were already using forearm displays, any chance
mutation which increased the visual stimulus could  be favoured
by sexual selection, if the opposite sex were attracted to the most visually
arresting forearms (or whatever).

Tony Canning
tonyc@foe.co.uk