In the lecture video, I noted two things. One, that humans (Homo sapiens) were almost wiped out 70,000 years ago after the supervolcano Toba erupted, creating a multi-year global winter. Only a small number survived, a few thousand at most, probably much smaller. As a result, humans are not very genetically diverse, compared to other primates. Also, I noted that around 40,000 years ago, there were at least four hominid species around - us (Homo sapiens), the Neanderthals, the Denisovans, and Homo floresiensis. That's how it was for millions of years - the last 18,000 years (after Homo floresiensis died out) is the only time in which there have been only one hominid species. What do think of this? Is it important that we are genetically so similar? What might be different if there were more than one species of humans around?