[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Copeing with mammals



John Bois (jbois@umd5.umd.edu) wrote:

> > Which clearly shows that they never competed.
 
<I took some time to superimpose the two graphs.  There is some overlap on
the temporal axis...but very little.  Rather than a replacement of extinct
species, it looks like a classic case of competition/predation.>

  I follow David in taking little time to see the hole in this argument
(at least as present): if two species have any form of overlap, be they
both herbivores, omnivores, or carnivores, but show they were adapted for
different foods, they cannot, _cannot_ have competed. In the example,
hesperocyonines being small, relatively opportunistic dogs whereas
borophagines, even the smaller ones being more robust crackers, would have
distinct niche separation, they cannot have competed one another to cause
the former to be "eliminated" by the latter. What the study suggests is
that, however, any event of nature can cause a group to dissapear or die
off because of hyper-specialization: if you can't change with the times,
you're erased from history. The data shows a trend in dog groups to large
size, showing that groups were becoming specialized: when the borophagines
first appear, they are small, and the hesperocyons large ... at which
point does the smaller dog manage to outcompete and eliminate its larger
contemporary?

David Marjanovic wrote:

<<Nothing dead or alive can compete with a pteranodontid or azhdarchid.>>

John Bois replied:

<Albatrosses.  It is conceivable that their juveniles are better than
pteros at avoiding long range aerial predators (e.g., frigate birds?). If
so, they are better competitors.>

  No one can say this without knowing an azhdarchid or pteranodont
juvenile. It can be thought of, but it becomes a fantasy when one
introduces such "facts" without there being anything to base them off of.
Similarly, the dead giant pterosaurs apparently fed at the water's surface
of a massive inland sea, "scooping" and "skimming," and this is a distinct
contract from albatross adults. Prove it otherwise. With proof.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
__________________________________ 
Do you Yahoo!? 
Meet the all-new My Yahoo! - Try it today! 
http://my.yahoo.com