We’ve had a busy summer–traveling, going to the movies, releasing a book–leaving less time to talk about current research. And there have been several recent stories making the rounds in Christian circles. They touch on questions many of us have about Adam and Eve, Noah, and the early history of the world. So I thought it might be worth a quick round-up of that research and what we’ve learned from it.
Did most animal species originate at the same time? A paper on DNA barcoding of species gained notoriety when it was imprecisely summarized as implying that 90% of animal species are about 200,000 years old. The paper itself does not make that claim, in no small part because the data don’t support that conclusion. What was actually observed was that many species, regardless of their population size, had similar amounts of diversity (numbers of variants & number of mutations between variants) in the sequence of one specific small stretch of DNA. In some reporting, this observation was incorrectly used to reason that these species have all been diversifying for the same amount of time, presumably because of a similar origin time. But this particular stretch of DNA has not been validated for estimating population size and history; it is mitochondrial DNA which has different dynamics than most DNA. And other DNA and fossil evidence that points to different conclusions about species’ histories. So while this is an interesting finding worth following up on, it should not be the basis of any strong conclusions.
What does a Neanderthal-Denisovan hybrid mean? Probably not much, practically speaking? At least, it doesn’t really change the picture with respect to questions Christians care about. We already knew that both Neanderthals and Denisovans were ancestors of some living humans. So other Neanderthal hybrids and Denisovan hybrids with other hominins must have existed in the past. Thus Neanderthal-Denisovan hybrids are not completely unexpected. And this finding doesn’t change anything about our understand of common ancestry with apes or our relationship to other ancestral hominins. My take is that this discovery contributes more to our understanding of our ancestors (and their relatives’) past behavior and social interactions than to our understanding of their biology.
Can we make fossils in a day? Sort of! Or perhaps more precisely, we can reproduce certain features of fossils with laboratory techniques. And that can be very useful for understanding why certain features are preserved when others aren’t, and how that preservation occurs. But it doesn’t mean that all fossils found “in the wild” were created in a short period of time. We already had reasons to think fossils, or features of fossils, could be reproduced in a short period time, and also good reasons to think some fossils really are quite old. So while this technique will be fruitful for research, it’s unlikely to change our timeline of natural history.
Since the fall semester is ramping up, I wanted to take one last chance to call your attention to my request for your input on future directions for my blog posts. Any responses between now and next Wednesday, September 5, 2018 will still be eligible for the book giveaway. Thanks!