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Author Topic: Horizontal vs. Vertical  (Read 5298 times)

Offline Supercryptid

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Horizontal vs. Vertical
« on: 07/04/2005 19:52:36 »
Since there isn't a forum dedicated to biology in general, I suppose this forum will do.

My question concerns the mechanics of jaw structure in animals. If you'll notice, all vertebrates that have jaws possess vertically-clamping jaws (that is, they open and close by moving the mandible up and down against the maxilla), or so far as I know. However, when you look at many arthropods, you find the opposite, in which horizontally-clamping jaws seem to be favored (two mandibles that move side-to-side). Is there any particular reason for these differences?

For instance, is there any particular advantage that vertically-clamping (VC) jaws have for vertebrates that horizontally-clamping (HC)jaws just don't have? If there were a bear with HC jaws instead of VC jaws, would it become a less effective predator? Likewise, are VC jaws inappropiate for a hypothetical arthropods?


 

Offline Ultima

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Re: Horizontal vs. Vertical
« Reply #1 on: 08/04/2005 00:07:45 »
With horizontal don't both parts of the jaw move, but with vertical only the bottom does, wouldn’t the vertical type be better for tearing and pulling? and horizontal would be better for gnawing and gathering...

wOw the world spins?
« Last Edit: 08/04/2005 00:10:36 by Ultima »
 

Offline ADD HAHAHA

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Re: Horizontal vs. Vertical
« Reply #2 on: 08/04/2005 05:54:58 »
it gets even more confusing when u think about thinks like manta rays(grinding plates 4 mouth) or the echina more grinders.

so how do those fit in as well??? :D
 

Offline DoctorBeaver

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Re: Horizontal vs. Vertical
« Reply #3 on: 13/04/2005 13:37:37 »
Do arthropods get lockjaw?
 

Offline rahonavis

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Re: Horizontal vs. Vertical
« Reply #4 on: 01/09/2005 22:53:54 »
All I can think is that a vertically clamping jaw allows for differences in the dentition of each of those jaws without spoiling the animal's bilatteral symmetry(see fig. 1).

fig. 1 :D

Oh, and a dinosaur has recently been found named Nigersaurus taqueti which has a 'hoover-shaped mouth' with latterally oriented teeth, rather than the usual horizontal orientation, giving it the appearance of a hammerhead shark. So there is room for variation on the vertebrates' vertically clamping jaw morphology.
« Last Edit: 02/09/2005 20:15:32 by rahonavis »
 

Offline ukmicky

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Re: Horizontal vs. Vertical
« Reply #5 on: 02/09/2005 20:51:26 »
Evolution chose it as the best compromise for the way we live and feed. Didnt we all come from the sea.
 
Some fish feed from the surface which would require vertical operating jaws, even bottom feeders would be better off with vertical jaws.

Also maybe vertical jaws allows for better streamlining and faster escape speeds in water , and also with vertical jaws the teeth are placed top and bottom making it easier for us to keep our food between our teeth when we chew.
« Last Edit: 02/09/2005 23:55:15 by ukmicky »
 

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Re: Horizontal vs. Vertical
« Reply #5 on: 02/09/2005 20:51:26 »

 

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