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Rob Sheldon: How we know the 558 mya animal Dickinsonia remains really contained fats

Recently, some readers asked whether the recent Dickinsonia fossil “fats” find from 558 mya featured cholesterol. Our physics color commentator Rob Sheldon explains further: Cholesterol was not found by these researchers, nor did they make announcements of soft tissue in a fossil. What they did find were the breakdown products of cholesterol called “sterols”. Plants make phytols that break down similarly. There might be hundreds to thousands of breakdown products of these biochemicals. When these materials are run through a mass spectrometer, the device sorts them by chemical weight. Really good mass specs (like the ones I used to design for NASA) can even separate isotopes of carbon and hydrogen. Then a simple molecule like CH4 might have four or five Read More ›