Extinct Humans

Of the several books that I have read recently on paleoanthropology and human evolution, I find this one the most helpful. This is partially because the authors are anatomists, systematists and pragmatists, largely untouched by 'political-correctness' and partially because I agree with them.Human evolution has been characterized by the development of multiple hominid species over the past several million years. These species can be loosely grouped into gracile and robust australopithecines; Homo habilis; H. erectus; H. ergaster; H. heidelbergensis; H. neanderthalensis; H. sapiens and probably a number of others. The authors are open-minded about the Iberian 'Los Huesos' site, but believe these numerous fossils may represent even another separate human species.Part of the problem with a systematic segregation of the various human species has to do with morphologic differences based on sex, age, individual variation and subspecies [racial] variation. The same species also tend to vary with time, which is a form of subspecific variation. The problem is multiplied by the fact that, with the exception of H. neanderthalensis in which DNA has been recovered, species separation is based almost entirely on bony features i.e. soft tissues are long gone. It's a little like separating lions and tigers based strictly on bony features. It would be tough.The authors are tentative about the exact sequence of species that led to H. sapiens and H. neanderthalensis but are convinced that these groups are separate species and cousins rather than descendants one from the other. They believe that early hominid species may have faced sequential extinctions via the usual natural processes but that the extinctions of later human species may have been, directly or indirectly, the consequence of the later and culturally evolved 'varieties' of H. sapiens, which interestingly and quite probably significantly, arose in Europe.H. sapiens and H. neanderthals overlapped timewise and geographically in Europe and Western Asia. It also seems true that H. sapiens overlapped in a similar way with H. erectus in southeast Asia. In both cases the outcome was the same with only H. sapiens remaining.I was fascinated by the authors' descriptions of possible early H. sapiens and H. neanderthal interactions in Israel. They seemed to overlap for tens of thousands of years, a time when both groups used similar stone technologies. When sapiens developed more sophisticated technologies, Neanderthals mysteriously disappeared. Something similar may have happened in Europe. At virtually the same time that sapiens was producing magnificent art, Neanderthals disappeared from the surface of the Earth. This doesn't mean that Sapiens and Neanderthals lived in peaceful coexistence at any time but it is entirely conceivable that there was an ancient 'balance of power' as long as both groups had similar technologies. Once Sapiens graduated to superior technologies and techniques, Neanderthals seem to have--perhaps very gradually--disappeared.The authors postulate that something happened rather suddenly to sapiens' populations that caused them to produce superior weapons and art. They don't know what this may have been but it may have been complex language, something the Neanderthals may have lacked.Because of the date of this book, the authors don't include recent information about the fascinating H. florensis find although I would be interested in their take. For the same reason they don't include the very recent information about the supposed presence of Neanderthal genetic material in our, Sapiens, genome. I would comment, though, that because of recent common ancestor, we will share more--probably far more--than 99% of our DNA with Neanderthal. Interpretation of data of interbreeding following the full development of Sapiens and Neanderthals must be cautious. It also must be confirmed by multiple laboratories. It is not impossible, at least, even if the two species were terrified of one another. It is not inconceivable that, either by predation or combat, a Neanderthal infant may have been 'captured' by Sapiens hunters and given to a woman who had recently lost a child. If such a Neanderthal were raised up in such a tribe, it might very well have been accepted and interbreeding would then be a real possibility.One thing I want to mention, in hopes that the authors will read this. Much has been made about early--and later--hominid meat scavenging. It may very well have occurred but there is an important proviso. I'll give a personal experience. I was raising quail and pheasants and began to have an unusual die off. I autopsied a bird and found the crop full of maggots. I knew instantly what happened--the birds had died of botulism. Birds and many mammals have Clostrium botulinum [bacteria] in their guts. Under anaerobic conditions, such as following death, these bacteria produce a potent toxin. A bird or two had died of other causes and I hadn't noticed them. Clostridia in their guts produced deadly poison. Flies laid eggs on the dead birds and the developing fly larvae [maggots] became contaminated with the same botulism poison. Healthy birds came by, pecked at the maggots and poisoned themselves--much like taking poison pills. More birds died and the process continued....Human beings [H. sapiens] are exquisitely sensitive to botulism poisoning. Most scavengers, rather understandably, aren't. A turkey vulture, for example, was 10,000 times the tolerance for botulism toxin as does a human. It is even conceivable that the foul odor we detect on rotting meat is nature's way of telling us to 'stay away.' Natural selection.Most of the carnivora are very much meat scavengers. A wolf, African lion or leopard will eat things that smell so bad as to turn your stomach. Predictably they will have a high tolerance for botulism toxin. So what are the possibilities:1. some species of early hominids were highly botulism tolerant [unlikely in my opinion].2. hominids, both early and late, would scavenge only from fresh carcasses [this, no doubt, did occur but is attended by the considerable danger from the carnivores that had brought the dead animal down].3. hominids, both early and late, didn't depend much on scavenging. They killed most of their own meat.Comments?

Paleoanthropologists are a little sensitive about their field of study and how it is overshadowed by genetics and evolutionary biology. As such we can forgive Ian Tatersall for the parts of the book where advocacy for his position becomes a bit strident.The basic argument of EXTINCT HUMANS is that throughout the evolutionary history of hominids there have been at least 15 species of humans, some of which coexisted. All but Homo sapiens are extinct. Naturally there is no argument about the extinction of other hominids, but other aspects of this position are not universally accepted. There are many other scientists that argue for a linear descent of man from Ardipithecus ramidus through Australiopithicus, Homo habilis and Homo erectus to us. These opposing camps are called "splitters" and "lumpers". Splitters see a great number of less variable species wheras lumpers see few species with greater variation. Ian Tattersall is one of the better known spokepersons for the splitters. As Jerry Seinfeld would say 'not that there's anything wrong with that', and we should applaud the use of these names by scientists as a good sign of their not taking themselves too seriously. That's on the surface though because beneath the cute names are some very strongly argued positions.What seems to bother Mr Tattersall and what comes through in his book is that the linear descent lumper theory owes a lot to two scientists who were not even paleontologists. He frequently refers to Ernst Mayr and Theodosius Dobzhansky as the source of this misguided theory and in explaining why the splitters have historically been rejected he says: "how could anyone, much less a bunch of paleoanthropologists who were not equipped with the supposedly more biologically informed backgrounds of Mayr and Dobzhansky, disagree with them?" He says that "No one could. Or, at least, no one would who didn't want to be accused of being anti-evolutionary."There is too much of this washing of paleontological dirty laundry here and it is in fact rather unnecessary as recent fossil finds are much more supportive of Tattersall's views. The recent discovery of Kenyanthropus platyops by Meave Leakey - the 3rd generation of that family of Kenyan hominid hunters has shown that there are in fact not only previously unknown human species but this one might also be a new genus.Where this book excells is in it's portraying and explaining the fossil record of humans. There are numerous figures, charts, maps and photos. The chapters are thorough with their explanations of the different stages of our evolutionary history. Chapter 6 subtitled the "Great Diaspora" looks at theories of how and when Europe was colonized. Such discussions naturally look at the "African Eve" theory of hominid origins and this book spends sufficient time on it. In summary you could say Mr Tattersall takes an extreme taxonomic view of human evolution; somewhat like a compulsive compiler of lists or an obsession with putting each thing in it's proper place. This is best illustrated with his species classification of Homo fossils as follows: erectus (Asians), antecessor (Europeans) and ergaster (Africans).Critics point out that humans are more variable morphologically than any other primate species but this variation is within group. Geneticists argue also that genetic variation is much less than morphological variation. Together this seems to say, Kenyanthropus platyops notwithstanding, lumpers with their arguments in favor of fewer and more variable species still have a point.The irony with science writing is that for every interpretation offered and truth discovered there is always another opinion. It certainly applies here and it means we cant be satisfied with the single view that EXTINCT HUMANS offers. It makes for some further interesting reading.

No matter how much you know, or how little, this is the book you have to read. Both of the authors know what they are talking about, explain in great detail what we know and how, don't talk down to you, don't go on tales of fantasy. They look at the fossil evidence, checking out the original material with their own eyes, and give us the facts, with a touch of imagination and humor.

just what i needed and wanted

I think after the Scientific American review, I was expecting a sort of magisterial overview of the state of the art. Instead, this is a lucid and even entertaining argument for what appears from the text to be a rather extreme (minority) position along the lumper vs splitter spectrum.Tattersall and Schwartz's basic premise seems to be that hominid evolution should be just as bushy as the evolution of all other animals. Their hobbyhorse is the way that notions of the Ascent Of Man (the Great Chain Of Being) have hobbled paleoanthropology and caused it to lump far too many of our extinct cousins under the more emotionally resonant Ancestor rubric. So far so unexceptional to any reader of Gould et al, and they certainly make a good case for assigning various specimens to their own species, but all too often they present not even a strawman version of the opposition's reasoning.This is a shame, because the book is well written, beautifully produced, and accompanied by fine photographs and drawings. But it's not at all cheap, and for the money I'd rather have a survey, not a screed. Borrow this one from the library.