Ever Wonder Why Cold Treats Cause That Zing in Your Teeth? The Answer Lies with This Ancient Armored Fish!

Did you know that our skeletons can be traced back to a jawless fish from over 500 million years ago? Yara Haridy, an evolutionary biologist at the University of Chicago, shares this fascinating fact to highlight our connection to ancient life. According to her, understanding this history helps us appreciate our environment and each other better.

Haridy recently published findings in Nature, revealing that the sensitivity in our teeth is rooted in the exoskeletons of those ancient fish. This sensitivity is why your teeth may ache when you eat something cold or visit the dentist.

So, how did our skeletons develop? Haridy points out that soft tissue relies on a hard framework — a skeleton — which classifies us as vertebrates. But when scientists looked back to find the earliest vertebrate, they stumbled upon Anatolepis, considered a potential ancestor. Haridy’s team used X-ray technology to analyze its fossil, originally thought to have simple armor-like structures.

Surprisingly, she discovered that Anatolepis was actually an invertebrate, more akin to spiders and scorpions than to vertebrates. This pushed the timeline for vertebrate evolution back by 20 to 30 million years. Haridy admits this was disheartening since it challenged her research foundation.

With guidance from her advisor, Neil Shubin, Haridy pivoted her project. They focused on the similarities between the armor of invertebrates and vertebrate teeth. Why do these structures look alike? Haridy explored this question further.

Shubin suggested examining the sensitivity aspect. The armor of ancient fish was not just for defense; it likely served as a sensory mechanism. By looking closely at modern fish, Haridy found that their tooth-like scales contain nerves, similar to our own teeth.

This discovery implies that ancient fish used their armor to sense their environment, which could lead to a greater understanding of how those traits evolved into our current teeth. Haridy emphasizes that these adaptations have persisted through time.

Paleobiologist Joseph Keating, who reviewed the study, believes insights into skeletal evolution could shed light on abnormal growth patterns in humans. He explains that the developmental pathways crucial for bone growth were established in jawless fish 480 million years ago, which are relevant to certain diseases today.

This research not only reveals the origins of tooth sensitivity but also connects us to ancient history. Our teeth, a modern adaptation, are a testament to evolutionary progress from those early armored fish. So, the next time you experience a toothache, remember: it’s part of a much older story stretching back to the depths of the ocean.

For more on evolutionary biology and recent discoveries, check out reputable sources like NPR and Science Daily.

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