Re: Two more gaps in the fossil record

Cliff Lundberg (cliff@noe.com)
Fri, 15 Oct 1999 19:59:44 -0700

mortongr@flash.net wrote:
>At 10:07 AM 10/15/1999 -0700, Cliff Lundberg wrote:
>>How do we know it's *transitional*? If we know it's transitional, how do we
>>know in which *direction* the transition is occurring? Maybe all we can say
>>is that it's *intermediate* morphologically. If birds generally come later in
>>the fossil record, how do we know they didn't exist as a rare type for a long
>>time, prior to becoming widespread?
>
>We don't. That is one of the things about the fossil record that is little
>known. However, if you are engaged in an exercise of doubt, to see how
>much data you can doubt, then no data will suffice for any conclusion
>whatsoever. What one must deal in is probabilities. It is highly probable
>that birds came after dinosaurs and it is highly probable that hollow boned
>animals were not alive too much earlier than this creature. There is
>selective pressure against hollow bones among land dwellers

As to believing in evolution in general, a few fossils more or less mean
nothing. Being convinced of the reality of evolution, my interest is in
thinking
critically about it, and criticizing those would brush aside problems in the
interest of putting a solid front against anti-evolutionists. A favorite
subject
of doubt for me is the arranging of known animals in supposedly phylogenetic
series, and the hasty popping-in of every new fossil find. I guess if a
scientist
were to say 'This is odd, I don't know how this fits in', there would be no
press
release, no grant, no promotion. And no blow against creationism.

As to the matter of hollow bones, one may wonder which came first, the
light hollow bones that facilitate flight and rapid respiration, or the flight
that brought selection pressure for such bones. There may have been niches
in which lightness and high metabolism was advantageous for a terrestrial
organism. For example, in trees or in dry open country, neither of which are
likely spots for fossilization.
-

--
Cliff Lundberg  ~  San Francisco  ~  cliff@noe.com