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Post by dividavi on Mar 1, 2023 19:47:28 GMT
Many Animals, Including the Platypus, Lost Their Stomachs www.smithsonianmag.com/smart-news/many-animals-including-the-platypus-lost-their-stomachs-180948103/Not only did those animals toss their stomachs out with the evolutionary garbage, they burned the genetic instructions, too
Rachel Nuwer December 4, 2013 Image: John Gould via Wikimedia Commons Stomachs evolved some 450 million years ago, but after giving this organ a test drive, on 18 separate occasions ancestors of contemporary animals switched back, reports Ed Yong on National Geographic. A team of scientists at the University of Porto found that platypuses, spiny echidnas and around 25 percent of fish species are among those animals that have returned to a pre-stomach state. Stomachs break down food, and just as the organ originally evolved to digest larger blocks of proteins, its de-evolution was driven by diet, researchers think. Yong explains how this might have transpired: Once an animal loses its stomach, it's unlikely to go back. In all of the stomach-less species the researchers tested (save for pufferfish), the genes that normally code for stomachs were completely missing from their genome. In other words, not only did those animals toss their stomachs out with the evolutionary garbage, they burned the genetic instructions, too. Rachel Nuwer | | READ MORE Rachel Nuwer is a freelance science writer based in Brooklyn.
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