Time for a better taxonomy.

Despite what is shown on the silver screen scientists are humans when all is said and done. And just like all other humans, scientists can be grouped according to such observed differences in behavior as their tendancy to oversimplify or to overcomplicate. From this we get lumpers and splitters. Although this sounds sophomoric, it has a certain utility. In addition to being in the lumper or splitter group, scientists can often be found in family groupings. So you might find a prominent person in a field of science who made discoveries of note, formulated a philosophy of the field he or she was in, and trained acolytes who followed up leads and made break throughs and went on to publish more work in the field and head departments of that discipline and eventually earn prizes, too. Look at Enrico Fermi and the physicists who surrounded and succeeded him in Chicago. Examine other fields, some of them somewhat dubious science--the "dismal science" of economics, for example. Look at Nobel prizes awarded to persons in science fields and you will see a number of family groupings. These prominent scientists and their families influence the thinking of their fellow scientists strongly and sometimes disproportionately. Take anthropology as a case in point. Splitters have dominated the fields of paleoanthropology and physical anthropology for a long time. (Just as we had too numerous to count sub atomic particles in physics for a long time--splitters hard at work, literally and figuratively--so we have two dozen, give or take a couple, different species of predecessor humans and subhumans back in time to an ancestor in common with our closest living relations on this planet.) But you know what comes next: pendula of all sorts swing to the right and then back to the left, so splitters eventually yield to lumpers and we arrive at a new understanding. This new understanding might arrive without any new data. But here I want to give an example of the opposite: new data arriving without any new understanding. Check out this abstract of a recent paper in molecular biology studies.



Curnoe D, Thorne A.
Department of Archaeology and Natural History, Research School of Pacific and Asian Studies, Australian National University, Canberra ACT 0200, Australia. d.curnoe@unsw.edu.au
Despite the remarkable developments in molecular biology over the past three decades, anthropological genetics has had only limited impact on systematics in human evolution. Genetics offers the opportunity to objectively test taxonomies based on morphology and may be used to supplement conventional approaches to hominid systematics. Our analyses, examining chromosomes and 46 estimates of genetic distance, indicate there may have been only around 4 species on the direct line to modern humans and 5 species in total. This contrasts with current taxonomies recognising up to 23 species. The genetic proximity of humans and chimpanzees has been used to suggest these species are congeneric. Our analysis of genetic distances between them is consistent with this proposal. It is time that chimpanzees, living humans and all fossil humans be classified in Homo. The creation of new genera can no longer be a solution to the complexities of fossil morphologies. Published genetic distances between common chimpanzees and bonobos, along with evidence for interbreeding, suggest they should be assigned to a single species. The short distance between humans and chimpanzees also places a strict limit on the number of possible evolutionary 'side branches' that might be recognised on the human lineage. All fossil taxa were genetically very close to each other and likely to have been below congeneric genetic distances seen for many mammals. Our estimates of genetic divergence suggest that periods of around 2 million years are required to produce sufficient genetic distance to represent speciation. Therefore, Neanderthals and so-called H. erectus were genetically so close to contemporary H. sapiens they were unlikely to have been separate species. Thus, it is likely there was only one species of human (H. sapiens) for most of the last 2 million years. We estimate the divergence time of H. sapiens from 16 genetic distances to be around 1.7 Ma which is consistent with evidence for the earliest migration out of Africa. These findings call into question the mitochondrial "African Eve" hypothesis based on a far more recent origin for H. sapiens and show that humans did not go through a bottleneck in their recent evolutionary history. Given the large offset in evolutionary rates of molecules and morphology seen in human evolution, Homo species are likely to be characterised by high levels of morphological variation and low levels of genetic variability. Thus, molecular data suggest the limits for intraspecific morphological variation used by many palaeoanthropologists have been set too low. The role of phenotypic plasticity has been greatly underestimated in human evolution. We call into question the use of mtDNA for studies of human evolution. This DNA is under strong selection, which violates the assumption of selective neutrality. This issue should be addressed by geneticists, including a reassessment of its use for molecular clocks. There is a need for greater cooperation between palaeoanthropologists and anthropological geneticists to better understand human evolution and to bring palaeoanthropology into the mainstream of evolutionary biology.
PMID: 12733395 [PubMed - indexed for MEDLINE]


Here scientists used the same technology as law and order investigators, paternity dispute family law practitioners, population geneticists, and state-of-the-art genealogists to look at our (human) molecular make up and compare us with others currently considered non human. To go with the law and order train of thought, killing a chimpanzee or a bonobo ape is not homicide. (For those who are not scientists but are nonetheless trying to follow all this: Homo is the genus and sapiens is the species. Killing another of the same genus as our own would be by definition Homo cide, or homicide.) But if you will read the abstract of Curnoe and Thorne's article again, you will see that these authors consider humans and chimpanzees to be in the same genus, or "congeneric." So, we should either join the chimps in their genus or they in ours. Better we keep ours and raise them up, so to speak. The ultimate "Old Boys' Club" of genus Homo is about to be opened up to the untermenschen. Literally and figuratively untermenschen, I should add. Just waiting for the lumpers to rise to the occasion.

A second point to be made is less practical but is even more revolutionary than the first. Just as the hundreds of identified sub atomic particles coalesced into a handful of pieces in the Standard Model of modern physics, we might soon observe some serious lumping of our two dozen or so ancestor species leaving us with but a handful. After all, if present day chimpanzees are congeneric with Homo sapiens it stands to reason that neandertals, and the various and sundry pre humans of the last million years were likely all in our species, or we in theirs. That's a lot of phenotypic variation for a minimum of genotypic variance. These rapid changes in our Homo sapiens structure and function came about with little or no change in our genetic make up. This spells ooparts. Chimpanzees and bonobo apes and a million years--one group on one side of the river and the other on the other side, and few observable differences in them now or in the past. Same species (in the new understanding but not yet in orthodox taxonomy) and nearly the identical genetic coding. Neandertals and us and five hundred thousand years--the former extinct for failure to adapt to climate change and us proliferating across five continents from ice age to global warming. With a paltry 30,000 genes we are managing our survival very well. (Some might say too well for what we have to work with.) Does anyone wonder whether we received outside help? Maybe this is not enough to warrant the existence of an omniscient, omnipresent, all loving Creator God whose special project we are; but an objective observer might consider the possibility that we modern humans received a genetic "uplift" sometime in the past 100,000 years. This would be within the scientific and technological capability of gods who knew then a bit more than we humans know now. (And these gods would almost certainly have uplifted our ancestor species, their untermenschen, for the gods' advantage, not for ours. This means that the Garden of Eden was likely a slave plantation producing food and wine for the gods, not the paradise lost of Adam and Eve.) Time to read those ancient cuneiform tablets from what is now our war zone and reread the second hand account in Genesis--now that humankind's own technological and scientific abilities are sufficient to allow an understanding of what is written in them.

I doubt any school or family of physical anthropologists or paleoanthropologists is going to switch en masse from splitter to lumper on the basis of current molecular biological data. But sooner or later you can bet it will happen. We will look at things differently with or without additional data. And just as a young couple expecting a baby turn to thinking of names, paleoanthropologists and physical anthropologists might start thinking of names for their (new and improved) taxonomy.