How Vertebrates Got Teeth... And Lost Them Again

As revolutionary as teeth were, they would go on to disappear in some groups of vertebrates. But why?

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Produced by Complexly for Digital Studios

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[MargoMB]

'which came first, teeth on skin or teeth in mouth' is a question I never could've imagined would need to be asked and it's really weird and strange to think about but this is exactly why I love this channel so much! So many topics I had no idea even existed but I always come away feeling like I definitely needed to learn about it. I'm a little disappointed the video didn't go into more depth on 'teeth on skin' though, what were the advantages to that, why did it develop, etc.

[andrearivera]

I think it would be interesting a video about ears, the outer part of them, when they first show up in the fossil record and why (I think) only terrestial mammals have them.

[rycolligan]

The Ballistic Tongues is definitely a solid band name if ever there was one.

[rolfhansen]

Really enjoy kallie’s story telling. Her passion for the subject is evident. Thank you

[MidnightWonko]

I think I read somewhere once that having beaks instead of teeth also helped drive down the amount of time between when a bird lays an egg and when that egg hatches. That seems to me like that would be beneficial for creatures living in the aftermath of the K–T extinction.

[aeddonmckaba]

One of my biology teachers explained part of the reason birds lost teeth was because enamel is the densest material in our bodies, and it helped conserve weight for the same reason that female birds have only one functioning ovary. I wasn't sure how founded that would be, but it was something that stuck out to me.

[ShaunCKennedyAuthor]

"Why would you prefer a beak to teeth?"

"Ummm... I guess you've never had a toothache."

[pavelmusiol]

I enjoy every episode, but it is evident that the speaker matters as much as the content. If not more. This lady´s genuine enthusiasm is infectious. Her colleague´s humour is refreshing. I hope to see more of this duo.

[spheresong]

Something occurred to me watching this, we get lots of content about the fist land vertebrates but do we know much about when arthropods moved onto land? Was there a single major movement by arthropods or had their subphyla already split off and had separate events leading them to become partially or fully land dwelling.

[jcortese]

I just want to say that the concept of a "ballistic tongue" is one of the cooler ones in biology.

[sussekind]

In the early stages of chicken embryo development, the embryo does indeed grow teeth in it's proto-beak (for lack of a better term). However, they are then reabsorbed a short time thereafter. It does show however, that at one point, the chicken's ancestors, did indeed have teeth (T. Rex certainly fits that description).

[robhacklblumstein]

I think it's a great illustration of the way evolution works that several lineages of birds, including waterfowl and the Pelagornathids, have evolved beak structures that function like teeth. Natural selection can only work with the biology an animal already has.

[filmboyultimate]

Tungsenia: allow me to introduce you a new innovation, teeth!

*millions of years later*

Most animal groups: these teeth get in the way, let’s ditch them for something less biologically expensive

[roastchestnut]

Another evolutionary "cost" of teeth could also be that they can get infected - you don't have that risk with a beak. They are also more easily damaged in general.

[BigBossMan]

I love how full of information PBS Eons videos are while being quick and easy to watch. Perfect for work breaks

[Smiler]

Hey! I was wondering if you could do a video about how insects evolved out of the oceans. We all know how fish first walked onto land, but how did bugs get onto land?

[adityamohan]

Beautiful video.
1. Though amphibians use tongues for feeding, the tongues cannot completely replace the teeth. Frogs actually push their eyes down to bring the food into their tract.
2. Also seeing grass in Permian era illustrations irks me a bit.

[Magmafrost]

The idea that no land vertebrates were eating plants until about 300 MYA is absolutely wild, how have I never heard about this before?

[nicnac.]

So excited for this episode! I remember asking for the evolution of teeth. Didn't think it was important enough to get its own episode

[duybear]

Same thing happened to eyes. Animals needing great eyesight evolved them. Animals not needing great eyesight lost them. Even when they evolved from predecessors previously having acute vision. (You should do an episode on the evolution of eyes)