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Re: primers



Mike Lovejoy (michael@palaeoproductions.fsnet.co.uk) wrote:

<If these animals' characters had been listed purely from skeletal
material, the way we have to with dinosaurs, would the results still be
the same?>

and David Marjanovic (david.marjanovic@gmx.at) wrote in reply:

<This is actually slightly unfair. Hardly any two Mesozoic dinosaurs are
as  closely related as breeds of dogs.>

  Well, a small correlation to this is that for the most part, pelage and
size variation in breeds are often the only variations noted between them.
There are breed groups, such as hounds, "hunters," terriers, mastiffs,
etc. that are instantly recognizable by variation in the skull, but some
variation, such as the American bulldog's (pitbull, not to be confused
with the British bulldog, which we'd call a mastiff) underbite are an
example of arrested development of the snout and exaggeration of the
dental development. There is NO evolutionary advantage to pug's noses
being so short, and it is, but for Human involvement, to the dogs'
disadvantage to have such a snout. Otherwise, selective breeding, as put
forward by Darwin himself (and others like Elliot Smith) is _artificial_,
not natural. Such variation can be considered ill to apply in a general
framework. So true for cat breeds, pigeon breeds, chicken breeds....

  Additionally, several studies of various species groups of snakes,
lizarsds, mice, various plentiful and tiny birds (small ecological area,
therefore great competition for niche space and thus great drive to adapt
and vary, perhaps, explaining why smaller species are more plentiful than
larger ones) are based almost entirely on geography or coloration and
size, and veyr, very little to do with morphology. In some cases, a unique
morphology of a muscle or a dimple in a bone may be used to set species
apart, but traditionally most species groups (and this is especially true
for some coleopterans) are not always based on morphology. Now, more about
coleopterans: I can only say this with a little reservation, since I am
aware that coleopterans often vary a lot in exoskeletal morphology, but
not extremely so, and apparently not always with "specific" differences,
i.e., they only vary randomly among their own subspecies or variants [I
don't know of any hybridists or breeders of beetles, so this term may not
apply].

  Thus, it is possible that *Diplodocus longus* and *Triceratops horridus*
and *Tyrannosaurus rex* represent groups of extensive subspecific
variation, simply by expansion and habitat and time these species were
around spawn such variation in living animals, even large species (for
example, the varieties of orca, distinct populations [by sight and
morphology!] of African elephant, and so forth).

  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)


                
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