Sunday, March 14, 2010

Why do sharks lose more teeth that people?

Because they never stop growing them. Their survival has evolved to depend upon their teeth, so their supply of teeth never ends. They have row after row of teeth, which keep growing back as they are lost. If you lost teeth like a shark did (because yours don't grow back), you'd have dentures by the age of 22.





Good Luck!

Why do sharks lose more teeth that people?
For starters, they have a heck of lot more of them.





Sharks' teeth and jaws are designed to allow them to loose teeth much more easily than humans. Their teeth are set up so that if they loose a tooth, another one can move right up and take the lost one's place (not instantaneously - I'm assuming it takes some time, but the point is, there's one there to replace it).





People on the other hand have to hang onto the teeth they've got. Most of us only get two sets - our baby teeth and our permanent teeth (unless you want to count false teeth!)
Reply:Those are good answers. But there's a different and interesting aspect if you turn your question around.


Most vertebrates have multiple generations of teeth (this is called polyphyodonty), and the teeth are either attached looosely to the jaws, as in sharks, bony fishes, amphibians and many reptiles, or are partially supported by a lateral bony shelf in the jaws. The exceptions are adaptations to particular types of food.


In the particular case of sharks, which are predators, teeth grow on a scroll-like fold of the internal part of the jaw and are 'transported' outward and forward continuously; the outer teeth are the oldest and the ones that are lost. In fact the scales of sharks, which are very similar to teeth, are also replaced continuously.


So why not ask another interesting question: Why do people (or mammals in general) lose less teeth? We have only 2 generations of teeth (diphyodonty), and this mammalian characteristic is related to our ability to chew food efficiently.
Reply:because they have more sharks can have over 1000 teeth and they when they loose one they always grow back even the adult teeth. Unlike people when we loose a tooth if it's a baby one it will grow back, but not our adult teeth and we humans have only 32 adult teeth including our all our molars.



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