Human evolution: bushier than ever (Introduction)

by David Turell , Saturday, December 04, 2021, 02:24 (1083 days ago) @ David Turell

One new opinion:

https://www.realclearscience.com/2021/12/03/there_are_a_lot_more_human_species_out_ther...

"Everything that’s been called Homo sapiens, isn’t.

In my opinion, far too many species have been lumped together into this one taxonomic category. The truth of the human story is far more complicated, with more species and even more genera than have been named, and more dead ends on the branches of the human family tree than have been recognized.

***

"I’ve continued to document the human fossil record with detailed descriptions and lots of photographs. And the more specimens I study, the more I realize that most of the species designations don’t make sense. If hominin fossils were treated the same way as nonhuman primates, specimens currently lumped into the same group would be allocated to different ones. We need to go back to taxonomic basics.

"Having studied so many human fossils is both a blessing and a curse. The “blessing” is that I can apply my theoretical and comparative background to virtually the entire human fossil record. The “curse”: I don’t always see eye to eye with other paleoanthropologists, who often focus on one or two “species,” a geographic area, or a period of time.

"We humans are the only surviving species of our immediate evolutionary group. This often leads people, including researchers, to make an intuitive but not necessarily correct assumption: The closer one gets to the present, the fewer contemporary species there should be.

***

"From my decadeslong study of recent human skulls from all continents, I’d say H. sapiens has a few key physical features. There is no continuous brow above the orbital sockets and across the nasal region. Our lower face is vertical and a lot narrower across than our cheekbones; you can feel this yourself. Most importantly, we’re the only living mammal with a true chin: not just a bulge but an upside-down T shape that often becomes triangular as a person grows older.

***

"All European Upper Paleolithic humans, on the other hand, such as from Cro-Magnon, do have all of these features, so they’re H. sapiens. I would say the oldest collected specimen of H. sapiens is from Border Cave, South Africa, which is perhaps as old as 174,000 years.

"In my view, the pot currently labeled H. sapiens contains specimens representing at least a few species, and these species are our closest extinct relatives. Even closer than Neanderthals and the recently described “Dragon Man,” proposed as Homo longi, from China.

"Many people think that DNA accurately reveals the picture of human evolution. But this isn’t true.

"First of all, DNA has only been successfully extracted from a handful of fossils, including some Neanderthals, some Upper Paleolithic and near-recent humans, a partial finger bone from Denisova Cave, and two bones from Sima de los Huesos, Spain. Since DNA usually degrades within 100,000 years, we’ll only ever have DNA from a minuscule fraction of fossils; DNA analyses are missing most of the pieces of the puzzle. And there are circular arguments: DNA is identified as, say, Neanderthal because the fossil was identified as such, and then it is used to identify other fossils as Neanderthal, even if they don’t look Neanderthal-like.

"While certain similarities between our DNA and Neanderthal DNA have been interpreted as evidence of the two species interbreeding, these similarities could just be run-of-the-mill features of the genome, common to many species.

"In the crush to embrace interbreeding as the source of human-Neanderthal molecular similarity, people sometimes forget to ask the question: If humans and Neanderthals actually crossed paths as often as molecular anthropologists claim—which is not supported by archaeological or paleontological evidence—would they have recognized each other as potential mates? I don’t think so: They looked too different. Even present-day hunter-gatherer groups have been observed to engage in violence when they encounter each other. And there is evidence from the 49,000-year-old site El Sidrón, that Neanderthals cannabilized other Neanderthals.

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"To me, however, all of human evolution, even well after our own species first emerged, is a mess of branches and dead ends. Our evolutionary history is complicated, and we should embrace that."

Comment: Argumentative voices add to our thoughts. I think the dhw theory is right on, but I come with a slightly different twist. God didn't want a free-for-all. God is too purposeful for that. Recognizing mistakes will happen in a free-flowing human living system as it is developed. many humanlike types scattered into many environments will naturally adapt many good attributes which will contribute to the final H. sapiens product.