SCIENCE
How do teeth help identify people’s origins?
Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Photograph by Joel Sartore, National Geographic
Discussion Ideas
- The Popular Science article says enamel is only found in vertebrate teeth. Do invertebrates even have teeth?
- No. True teeth are only found in vertebrates. Teeth are hard, bone-like structures that are attached, usually in a row or rows, to a vertebrate’s jaw.
- Many invertebrates have structures similar to teeth.
- Mollusks such as limpets, for instance, have a tongue-like, ribbon-like organ called a radula that is barbed with more than a thousand tooth-like structures.
- Arachnids such as funnel-web spiders have complex mouthparts called chelicera that act as “fangs.”
- New research tested scales from both fossils and extant fish with ganoid scales, and compared the scales’ proteins to proteins found in tooth enamel. What are ganoid scales?
- Ganoid scales, one of four major types of fish scales, contain the mineral ganoine. They are hard, solid, diamond-shaped scales found on ancient, weird-looking fishes such as gar, sturgeon, and paddlefish.
- So, how did ganoid fish scales become tooth enamel?
- They didn’t! (Evolution doesn’t work like that.) Research shows that ganoid scales contain enamel matrix proteins and other chemicals linked to enamel development in teeth. So, a better question is: How did proteins get from scales to teeth? Follow the ganoine:
- Some of the very earliest bony fishes had ganoid scales, but no tooth enamel—their teeth were “naked dentine.”
- “Somewhere along the evolutionary line, some of these ancient fish began to incorporate ganoine/enamel into other hard surfaces of their bodies, eventually … evolving with ganoine/enamel on their actual teeth, a trait that has been passed down the evolutionary line to almost all toothed creatures today, from humans to crocodiles.”
- They didn’t! (Evolution doesn’t work like that.) Research shows that ganoid scales contain enamel matrix proteins and other chemicals linked to enamel development in teeth. So, a better question is: How did proteins get from scales to teeth? Follow the ganoine:
TEACHERS TOOLKIT
Popular Science: Your Tooth Enamel Might Have Started As Fish Scales
Nat Geo: Clue to a People’s Origins video
Nat Geo: Limpets Sink Their Teeth In study guide
Nat Geo: Funnel-Web Fangs study guide
Australian Museum: Fish Scales
(extra credit!) Nature: New genomic and fossil data illuminate the origin of enamel