So scientists were grappling both with how life might have originated on earth, but they were also trying to figure out where life had originated on earth. And there are three competing ideas right at the moment. One is that life may have evolved in hydrothermal vents in the bottom of the ocean. One is that life may have evolved in little ponds on the surface of the ocean. So Charles Darwin actually first proposed this, and there's some evidence that this could've happened. And then there's other groups that are speculating that maybe life originated outside earth and landed on earth, maybe on a meteor, and the evidence for this is that the rate of genetic change is too slow to account for life having originated only three and a half billion years ago. So I'm going to show you three videos that discuss each of these ideas. The prevailing theory right now probably the best supported one is that life evolved in hydrothermal vents, and the reason that this is the theory that people like -- and I should say hypothesis. It's not yet a theory. The reason this is the hypothesis that people are looking at most carefully right now is that when you analyze genes that appear to be associated with the last universal common ancestor, or LUCA, all 355 of those genes, based on doing detailed analysis, we think were present at the very beginning. So looking at the last universal common ancestor, this would be the very first organism or organisms on earth. When you look at these genes, they seem to be very consistent with having originated in an organism that was living in a deep sea hydrothermal vent. So there was a paper published in Natural Microbiology in 2016. So this is what people are thinking right now. But I'm going to show you three videos that goes through each of these ideas. I think they're all very provocative and interesting.