April 1 is a terrible time to announce that we might have gotten two major steps in human evolution completely wrong, and that we have to start a new search for the various missing links that make up our ancestors. But this isn’t a joke; a lot about what we thought we knew about early human evolution might just be a crock.
It starts with Lucy, an Australopithecus afarensis fossil, which is, or rather was, the earliest known fossil of a human predecessor, dated to 3.6 million years ago. Discovered forty years ago, Lucy is an enormous find and important to our understanding of the past. Little Foot, another Australopithecus fossil and major link in the chain of human evolution, was first uncovered in 1994, and was dated to roughly 2.2 million years ago.
That is, until yesterday, when researchers at Purdue announced that, using isochron burial dating, an incredibly precise method, they found that Little Foot was actually 3.6 million years old. In other words, Little Foot didn’t descend from Lucy or some theoretical competing hominid, Little Foot was a contemporary of Lucy, and those “competing hominids” are no longer theoretical.
Not only do both have potential claim to being the true human ancestor, it indicates that there may have been multiple species of hominids running around millions of years ago that we don’t know about yet and who might also be the ancestor of humans. This both shakes up the accepted timeline of human evolution, and it means we’re going to have to go back through the fossil record and see what links up where.
There are a few caveats, here. Lucy hasn’t been subjected to the above dating method, and that might be a tricky prospect as it requires rock samples from around the fossil. We might learn she’s even older than we thought, for example, and that would raise still more questions. Either way, though, it’s an exciting discovery that shows we have far more to learn about where we came from as a species.
Source: Purdue University