Dr. Yara Haridi

How do you make your locomotion more efficient?

Sharks, they use the little spikes in their skin, these little teeth on the outside, their odontodes, to help basically with hydrodynamics.

The way that the water flows over their body is more efficient because of the little bumps all over them.

So maybe the early fish did that too.

So that's one other theory.

And then the last theory is that maybe it has something to do with sensation.

That maybe because our modern teeth are sensitive, maybe the outside ones are as well.

They're in the cabinets behind us.

Okay, give me one second.

Or homologous, right?

Because they have the same origin.

So the reason that we know that these odontos on the outside of the mouth are even related to teeth is because they're made of the same thing.

They're made of enamel.

They're made of dentine.

They have pulp cavities.

They have the same blood supply.

So they act very similar to our own teeth in the mouth, except that they don't replace the same way and they don't have a job in that they don't chew.

So how did we get teeth in the mouth?

Or how did you go from odontodes, things that are bumpy outside the head, to things that I can bite other fish with?

So that happened along, we assumed some time in probably the Devonian period,