There’s a philosophical quandary breeding in your mouth. Ever since Aristotle, philosophers and scientists have searched for the right way to classify living things. We call living things with feathers “birds,” but we can also divide birds up into smaller groups, like pigeons and storks. We can drill down even further, to different species of pigeons. But it doesn’t feel right to classify birds all the way down to every individual feathered creature on Earth. The fundamental unit of life’s biodiversity has long been the species. Charles Darwin named his book The Origin of Species for a reason.

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I love writing about evolution’s great transitions–from water to land, from ground to air, and so on. For our species, one of the biggest of those transitions happened when our invertebrate ancestors became vertebrates–complete with our distinctive backbone, muscles, mouths, noses, and eyes. For fifteen years, I’ve been writing about this transition, and it’s been exciting to see more fossils come to light that help us understand how our inner fish got its start.  For mynew “Matter” column in the New York Times, I take a look at one of the most interesting of these fossils–what one scientist has dubbed a benchmark for our understanding of the first vertebrates. It’s called Metaspriggina, and here’s a video of an animated reconstruction. Get the rest of the story here.

Continue reading “Hello, Great-Great-Great-Aunt!” →