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Re: origin of bats/suspect trees?
David Peters (firstname.lastname@example.org) wrote:
<You just shot yourself in the foot. Few to no molecular results replicate
morphology. And I did say "using morphology">
Very well. Ignore molecules, which seems easy I guess if you can find
detailed comparative anatomy for every odd, wierd or bizarre mammal one can
possibly fit into their analysis. Some don't exist, but this should be fine.
As for replicating morphology, this is actually not true. There are enough
genes who relevant to a morphological suite are known, such as sonic hedgehog,
which is perfectly capable of being mapped onto a morphological tree to
consider its effect. You can constrain one morph data set to agree with a mol
one, and map a character or gene appearance and determine compatability. Not
that this is hard.
<Blood work is not definitive. Morphology rules.>
I cannot see how this deserves much, if any comment, other than that
morphology more often than not a product of genes, not the other way around.
<Martin and Feduccia have just entered the room. The single character mindset.
Where's the suite Jaime?>
While David is correct in averring that manatees has rounded, oblate ribs, my
argument arose through comparative suites of features. There were comments
which were brought up about correlative features, such as elongated
forelimbs/elongated hindlimbs, elongated metatarsals and an elongated calcaneal
heel. Lower down I mention teeth, and this is even more securely true, and I
even mentioned sloths as an example of this, despite their differences.
Moreover, different animals in similar habitats have similar physiologies,
indicating that we can take a feature or suite of features and note that these
are related to that behavior; there are features tied to fossoriality,
arboreality, cursoriality, perching, brachiating, suspensoriality, opposability
of the hallux/pollex, etc.
<I said pedal, remember?>
Irrelevant. You don't think a constraint in habitat like suspension would
promote elongation of the phalangeal proportions, as it does in brachiating
apes? If not, then there should be even less reason why animals that do not use
the fingers for propuslion should ever have such digital proportions. Bats do
not possess the pedal proportions of brachiators, meaning that walking around
on their feet upside down is not a behavior they engage in in any regular
past-time. They do not, they lack such proportions, and thus one might expect
they lack such constraints any so-called "terrestrial bipeds" possess.
<and yet, there are patterns and suites of patterns. You've got to think about
the whole critter.>
Which is why I mentioned diet. Look at predators: dental anatomy must be
suited to rendering prey, the animal must be capable of processing
proteinaceous material, and the animal must have the energetic regime to
acquire the prey in the fIrst place. Finding a ziphodont crown can tell us that
the animal is suited to cutting flesh. If that crown had denticulations, we
would expect the prey item to possess possible muscular tissue, and likely be
vertebrate in nature. Possession of a jaw full of ziphodont teeth tell you the
animal is a strict carnivore. If the dentition is heterodont, with molariform
or incisiform teeth, then we can expect the diet to vary, and can expect there
to be more generalistic features of the body. This is what you can expect from
a single tooth. And that's just the apex of the crown.
Different animals with different evolutionary histories will convergently
acquire the same dental features given the same dietary avenues.
Jaime A. Headden