Imagine the tree of life. The tip of every branch represents one species, whether you're talking about humans, E. coli, tardigrades, baker's yeast or giant kelp.
If you follow any two branches back through time, you'll hit an intersection. That's the common ancestor of those two species. For example, the common ancestor of humans and chimps lived less than 10 million years ago.
But what if you keep going back in time?
Eventually you'll find the common ancestor for all vertebrates, then all animals and then all eukaryotes. And eventually, for all of life as we know it. That ancestor is called LUCA: the last universal common ancestor.
NPR science correspondent Jonathan Lambert joins Short Wave to talk about LUCA: What we think this single-celled organism may have looked like, when it lived and why a recent study suggests it could be older and more complex than scientists thought.
Click here to read Jon's original article in Quanta Magazine.
Have other questions about ancient biology? Email us at shortwave@npr.org — we'd love to hear from you!
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This episode was produced by Berly McCoy. It was edited by our showrunner, Rebecca Ramirez. The audio engineer was Gilly Moon. Tyler Jones checked the facts.
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