[In Our Time] The Evolution of Teeth

The Evolution of Teeth

11/04/2019 by BBC Radio 4

Web player: http://podplayer.net/?id=67771621
Episode: http://open.live.bbc.co.uk/mediaselector/6/redir/version/2.0/mediaset/audio-nondrm-download/proto/http/vpid/p07659pk.mp3

Melvyn Bragg and guests discuss theories about the origins of teeth in vertebrates, and what we can learn from sharks in particular and their ancestors. Great white sharks can produce up to 100,000 teeth in their lifetimes. For humans, it is closer to a mere 50 and most of those have to last from childhood. Looking back half a billion years, though, the ancestors of sharks and humans had no teeth in their mouths at all, nor jaws. They were armoured fish, sucking in their food. The theory is that either their tooth-like scales began to appear in mouths as teeth, or some of their taste buds became harder. If we knew more about that, and why sharks can regenerate their teeth, then we might learn how humans could grow new teeth in later lives.

With

Gareth Fraser
Assistant Professor in Biology at the University of Florida

Zerina Johanson
Merit Researcher in the Department of Earth Sciences at the Natural History Museum

and

Philip Donoghue
Professor of Palaeobiology at the University of Bristol

Producer: Simon Tillotson

Listen Date: 2019-03-08

Notes:

  • What a fascinating episode, though such a narrowly focused one. I learned that scales, teeth, and skin-teeth are all probably evolutionarily linked, though nobody knows quite how (or maybe they do but I couldn’t understand).
  • Digression of interest: how some organisms evolved toothlike organs from non-dentene components.
  • Also of interest: how teeth and the jaw both came around at the same time, and helped vertebrates take off like anything. The poor lampreys got left behind.
  • It was amusing hearing the lament of how difficult it was to find fish embryos to study because they were just discharged anyhow into the water and couldn’t be retrieved from their parents.

 

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