I was looking through todays Redeye (Chicago Tribunes mini paper) and saw a picture of the worlds shortest man (He Pingping of China) holding the finger of the worlds tallest man (Sultan Kosen of Turkey) and I thought if a paleoanthropologist dug these two up near each other they would never assign them to the same species. I wonder just how many finds have been misinterpreted and are actually the same species. I have definitely come around to the idea of anagenesis and I wonder if you could squeeze in something about Homo heidelbergensis perhaps in one of your post on Neanderthals or something. Did they evolve into moderns or die out?
Well, H. heidelbergensis is certainly a can of worms.
Here’s a start: If we and Neandertals descend from a single population that lived 350,000 years ago or so, where did that population live? If Africa, what does that make the Sima de los Huesos sample, at 600,000 years old? If Europe + Africa, then why was its genetic variation so low, and how was this continuity maintained? And, if it was, why would we assume modern humans aren’t part of this continuous population?
This is the difficulty.
Meanwhile re: variability – we may be near that point already. Consider that “H. erectus” now includes adult specimens with endocranial volume of 600 ml and others with 1200. That doesn’t exceed the extremes of normal human variation, but it is very unlikely you’d find this amount of difference in an equivalent sample size of humans. Or chimpanzees. Or gorillas.