Re: origin of feathers

["John V Jackson" <jjackson@interalpha.co.uk>]

-----Original Message--From: Earl Wood <candles@jps.net>Date: 13 April 1998
23:18

>John V Jackson wrote:
>
>> -----Original Message-----From: Earl Wood Date: 11 April 1998 08:12
>>
>> >        Would someone like to speculate on the possibility that pre
>> >feathers were brought
>> >about by the need to modify the skin in order to prevent serious sun
>> >burn from the sun
>> >or some other source of radiation which was probably very prevalent at
>> >different periods
>> >of time.  $0.02  worth.
>> >         Earl
>>
>> I would imagine early birds would have no greater need for this than
their
>> immediate predecessors, who presumably had the "standard" "reptilian"
>> integument.
>>
>> John V Jackson    jjackson@interalpha.co.uk
>
>     It has been suggested by some that temperature may have been the jolt
>needed tostart the growth of hair or feathers,  My thoughts follow this
idea
>and that over a good deal
>of time radiation ( U V ) might have contributed to the change from scales
to
>hair or feathers for insulation of this sort.
>     Thanks for your thoughts.
>     Earl


I think I'm just going to have to say "maybe" on that one !  Sorry if you
wanted better thoughts than that, but I haven't a confident clue as to why
pre-feathers evolved, only a few ideas.  However, I think UV wouldn't have
posed a very challenging problem to evolution unless the levels were very
diffferent during early bird evolution than now.

JJ