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Original Message by Philidor
Sunday, 22 December 2002 13:56
> Beaks have been described as having advantages in weight/balance,
Certainly exists. But how big it is, not compared to the monstrous teeth of
pretty much any mammal but to those of *Sinornis* or *Yanornis*, has never
Obviously depends on the diet.
> and ease of replacement.
Hm. On the one hand, you need lots of calcium and phosphate for teeth. On the
other, you need lots of protein for a beak... should therefore depend on the
diet and the geographical location of the animal that evolves a beak or
Hey. All wrong. Who says teeth and beaks are mutually exclusive? Why
shouldn't Ichthyornithidae, Hesperornithiformes and lots of pterosaurs have
had both -- assuming a beak is homologous to the gums rather than to lips?
> I'd add defense: better to stab with something sharp
> than to have the musculature and take the strain necessary for a bite.
If that were enough, we'd see a lot more beaks in amniotes, I think.
> Particularly with the bone structure getting lighter for flight.
The jaws of specialised carnivorous birds aren't that light, are they?
> Also, a beak makes selective capture of small items easier, whether animals
> or seeds.
This sounds best. Apparently it's also easier to lose teeth than to evolve
teeth with a complex shape to crack seeds.
> Like feathers, though, one wonders what provided the raw material for a
> beak to develop.
> Is there any known appurtenance made of beak-like material?
Yes, the egg tooth. There was a paper in Evolutionary Theory some years ago
that suggested that its absence in placentals and severe reduction in
marsupials has to do with the absence of beaks in both groups.
- RE: Beaks
- From: "Daniel Bensen" <firstname.lastname@example.org>
- Re: Beaks
- From: David Marjanovic <email@example.com>
- Re: Beaks
- From: "Philidor" <firstname.lastname@example.org>