A: To vary and evolve are two entirely different things. Species “do not evolve,” said Pierre-Paul Grasse in Traite de Zoologie, who, I might add, also argued that selection acts to conserve the genotype, rather than transform it or modify it or transmute it. Variation is not at all a sign of evolutionary progress, quite the contrary, variation does not allow for evolution beyond the species limit. Let’s go back to those Israeli specimens at Skhul, OK? Now the Neanderthal people normally look pretty much alike, right? But at the Mt. Carmel caves, there is tremendous variation, a sign of race mixing. Not evolution. Those different races overlapped in time and space; they “exchanged genes,” as it is politely said.
POE: Or they simply represent a highly variable population.
A: Variable? No, not a variable population, but more than one race or strain.
HIGGLEDY-PIGGLEDY
POE: Honestly, I find the discussion of speciation a bit troublesome. The only good hominid evidence is Neanderthal’s gradual separation from other populations, the process showing intermediate forms.
A: Or showing exogamous mating, which produced the chaos of races in the Stone Age, none of which are intermediate types, and many of which are indeed anachronisms, proving evolution impossible, because reversals don’t really happen. But retrobreeding does. Just think of all the embarrassing reversals in the record, reversals in skull thickness and brow size. Devolution? I don’t think so. Only mixing with lower types: back breeding. Pure and simple.
Neanderthal, who was the only hominid known in Darwin’s time, looked like a good candidate for human evolution (as Professors Schaaffhausen, Hrdlicka, Weidenreich, Coon, and Brace believed). But Neanderthal man was not only too recent a creature to have been our all-purpose ancestor, he was very much the contemporary—not the antecedent—of the modern Cro-Magnon people in China, Denmark, Portugal, and Israel. What’s more, Neanderthal mated with these Cro-Magnon neighbors, producing hybrid children of every imaginable blend.
Not our antecessor after all, Neanderthal man was then consigned to the dustbin of evolution—what else could be done with him?—and labeled an irrelevant side branch, dead end, extinct country cousin, whatever. He was not a forerunner of modern man, though it was still argued (to keep evolution alive) that the two share a “common ancestor.” But even this face-saving strategy, making the two types divergent offshoots of a shared parent, hardly solves the riddle. If Neanderthal and mods merely branched off from the same stem, how did the former get so “uncouth and repellent” and the latter so elegant and worldly—and in no time at all! Scientists, after all, say it takes up to five million years to speciate,*61 in which case we must admit there was not nearly enough time either for Au to turn into H. erectus or H.erectus to turn into Neanderthal—or for Neanderthal to turn into anything else. Even the “cousin” idea for Neanderthal took a beating at stratified sites where diggers found archaic H. sapiens at levels below Neanderthal—as in France, Israel, South Africa, Borneo, Australia.†62 A similar out sequence was also observed at Steinheim, Swanscombe, Ehringsdorf, Krapina, and other sites where the more gracile Neanderthal actually preceded the more extreme, chimpanzee-like one.
POE: We do find a general sequence of improvement in Africa from Au. afarensis to H. habilis to H. erectus to H. sapiens to H. sapiens sapiens.
A: Au. afarensis? Even Johanson, who figured Lucy was ancestral to later australopiths, admits that these descendants actually “became more and more exaggerated . . . [with] bigger back teeth, a dish-faced profile, a very large jaw.”6 But consider this: Even when we do find a reasonable progressive sequence, it is not at all clear whether one form led to the more advanced one. Has any form ever been found that is transitional between the quadrupedal primates and the bipedal ones? No; in every case the divisions between the classes, such as reptiles and mammals, are absolutely clear, with nothing indicating one type of organism converting gradually into another.
POE: Oh, I can think of many instances of transitional forms and behaviors, many intermediate lineages—between, say, the four-toed extinct horse and the single-toed modern one. Or even the chimpanzee, our closest relative among the primates, who spends a lot of time walking upright. Gibbons also walk on their hind legs.
A: Big deal. Birds are bipedal, too, for Pete’s sake. So were dinosaurs and the cursorial lizards who ran about on two feet. It’s like Dr. John B. Newbrough’s commentary on evolution in 1882, the year of Darwin’s death:
He chased the origin of man a little further back, and there left him. He failed utterly to grapple with the cause of different species. No real connecting link has ever been found between fishes and amphibians, amphibians and reptiles, reptiles and mammals, or monkeys and men. Darwin changed the word “creation” into “evolution” and there left it. The origin of life he left where it had always been. The doctrine of one species of animal being changed into another is easily squelched.
Figure 4.5. Dr. John B. Newbrough.
Protests, upon release of Darwin’s Origins, included England’s David Livingstone, Thomas Carlyle, John Stuart Mill, and America’s John B. Newbrough. Mathematician and physicist Lord William Thomson Kelvin disbelieved Darwin’s theory to the end of his life. Charles Lyell, a close associate of Darwin, also held out, not fully convinced of mutability or descent from “brutes”: “grand speculation” he called it (in Life, Letters and Journals, II). Sir John Herschel dismissed Darwin’s natural selection (which works at random) as the “law of higgledy-piggledy.”*63 Louis Agassiz, the founder of American paleontology, who led the study of natural history in nineteenth-century America, viewed all species as created by the Almighty Intellect, ruling out the possibility of recent species descending from earlier ones. Richard Owen, biologist, paleontologist, and Britain’s most influential anatomist, who coined the word dinosaur in 1842, did not believe man evolved from a monkey. William Whewell (the celebrated philosopher of science who coined the word scientist), said that we have a choice: accept the doctrine of transmutation or frankly recognize “the miraculous nature of creation.” He himself chose the second.
THE ISOLATION CARD
A: All mammals share a number of specific, defining, and diagnostic characteristics—hair or fur, mammaries, a diaphragm; no other class possesses these. All mammals have characteristics that are absolutely unique to mammals. All felines have characteristics that are absolutely unique to felines. All birds have characteristics that are absolutely unique to birds. The fishes of the Paleozoic Age are in no respect the ancestors of the reptiles of the Secondary Age, nor has it ever been shown that man “descends” from lower primates.
POE: But we do see microevolution, new species arising from preexisting ones, involving a gradual accumulation of small genetic changes. This was Darwin’s “insensibly fine gradations.”
A: Yes, the success of his theory is limited to microevolution—minutiae, like color changes in moths. But extrapolating from micro to macro, as did Darwin, is a hearty jump. If there is progression, why do breeders often encounter reversion to original traits? Back to square one.
POE: That’s artificial breeding; but in nature, the tendency to random variation was seen by Darwin as having unlimited potential, given enough generations, with no significant tendency to go back.
Varieties have strict limits . . . beyond which each species cannot pass . . . in any number of generations.
CHARLES LYELL, PRINCIPLES OF GEOLOGY
A: Are there no limits? Darwin’s critical error was assuming there were no limits to variations; bears, he surmised, could, given enough time, turn into whales. But change does not go on indefinitely. The species barrier, in the words of Arthur Koestler, entails “a restricted mutation spectrum.”7
Even Ernst Mayr, one of the leading twentieth-century voices of biological evolution, had to warn his colleagues that “every genotype seems to have limits to its capacity for change.” This he called genetic homeostasis, effectively a natural barrier beyond which selective breeding cannot pass. Indee
d, there are “severe limits . . . No bird can ever evolve into a mammal, nor a beetle into a butterfly . . . [because] a given species can tolerate only a limited amount of variation.”8
POE: Given nature’s tendency to continued progression, varieties move in very slight degrees, farther and farther from the original type, and there appears no reason to assign any definite limits—
A: To modifications, perhaps, but what about transmutation into a totally different animal? I don’t think so. This is why breeders say, if you get too far from the essential sheep, things break down, and eventually sheepishness reasserts itself. Beyond a certain point, further change is impossible.
POE: But in nature, over millions of years . . .
A: You get horizontal changes. But macroevolution (vertical), no. How will your advocates of continuity explain away the gaps, the missing hundreds of types shading imperceptibly one into the next? Paleontologists openly admit that the transitional forms required by Darwinism have never been found. Here lies cognitive dissonance. Split mind. Sustaining the paradigm—even though it has been checkmated.
POE: It is only because the process is poorly understood. One must take into account small populations and geological isolation—two indispensable features of evolution. It was isolation that led to morphological change in Drosophila (Hawaiian fruit flies) and also in the Galapagos finches. It is precisely such small isolated populations that give us the mechanism of change, because in large central populations, the gene flow (of any upgraded mutation) would get lost, diluted, swamped. But if that population is small and remote, the new trait can take hold. These peripheral isolates are the crux of speciation. This is how it happens. After a long period of isolation, the group diverges so far from the ancestral type that it becomes a new species, particularly when selection is strong enough to maintain genetic differences on the two sides of the mountain, desert, canyon, river, whatever. A demographic “bottleneck” sees development of new alleles under long periods of separation: the rise of a new population from a few individuals. The bottleneck is then followed by population growth.
A: As I understand it, such small isolated groups tend to die out. Moreover, such long-term inbreeding as you describe is not very likely to give any evolutionary advance.
POE: Let me offer Neanderthal as an example of peripheral development during isolation, which can then explain the coarse features of classic Neanderthal: arrival of the Wurm glaciation drove them into regions where they adapted to more Arctic conditions. Neanderthals were stuck in Europe during this long glacial period, separated from contact with others until the Upper Paleolithic. And this resulted in their unique, rugged, characteristics: bulbous nose, hatchet face, and so on. As a further example, arid conditions in Africa (brought on by an ice age beginning 186,000 years ago) may have forced humans into isolated pockets that contain enough water for survival. Then, with the return of lusher conditions 120,000 years ago, H. sapiens finally appeared—explaining the frustrating gap between archaic robust H. sapiens and more modern ones. Genetically isolated, the inhabitants would have developed the distinctive traits we view as modern—good chin, high forehead, and so forth.
A: How is it, then, that animal species often arise in places where isolation is impossible, as in certain lake systems. I dare say, the more isolating, the more they stay the same—rather than evolve. Take the long-isolated Australian Aborigines as an example—a people remarkably uniform in physical traits. I’d also like to mention that the Paleolithic landscape offers little support to any notion of separation, showing few signs of these cul-de-sacs. What can you point to on the map to prove the isolation mechanism? Such populations, in France, for example, lived close together in small areas, without any signs of a geographical barrier. In fact, I think the opposite is the case: plenty of crowding, overlap, and interbreeding.
POE: But you can’t get speciation without isolation. Without it, novelties would simply be swamped. The necessary variations would be lost in crossbreeding—unless preserved by isolation.
A: Your system of isolation seems to assume plenty of Lebensraum and meager population levels—which I believe is deeply flawed. Your reasoning probably also contradicts evolution’s fierce competition for resources (i.e., crowding).
POE: Only consider the Andes barrier, which clearly produced different animal species on the mountain’s eastern and western slopes; ditto on the two sides of the Amazon river. And look at hobbit: those folks on that island (Flores) were tiny—obviously subject to isolation and shrinking. Island dwarfing. The phenomenon is well known in the animal kingdom.
A: But not in the primates; even Peter Brown—of hobbit fame—owns that Homo floresiensis might well have arrived on the island already small bodied. So much for island dwarfing. Other Negrito groups have been isolated for tens of thousands of years and have not changed one jot or tittle or become a different race. No matter how long the pygmies and Polynesians live isolated from one another, in separate geographic locales, they are still the same species—Homo sapiens! And what about the opposite case, where sudden big changes are in evidence? How does that work with Darwin’s “insensibly fine gradations” over immense spans of time?
LEAPS AND BOUNDS
POE: Yes, in contrast to slow and gradual evolution, we know there is saltation, which is to say, abrupt jumps or rapid branching of species. Lamarck thought the evolution of a species could occur within a few generations or even one. But he was incorrect.
A: So at least we can agree that the fossil record does show the sudden appearance of life-forms—such as the true mammals in the Mesozoic. Baron Georges Cuvier, the great French paleontologist, while working in the deposits of the Paris Basin, saw sudden changes in geology and fauna; organisms would appear suddenly, remain unchanged for long periods, then disappear in a flash. Even dinosaur and mastodon appeared suddenly. Evolution? I don’t think so.
POE: Genetic recombination is one source of quick work, especially when large populations interact with much smaller ones. Plus DNA research now allows for quantum jumps in the record. But when paleontological science says sudden, you must realize the term is relative. It may actually mean thousands if not tens of thousands of years, even hundreds of thousands.
Genetic recombination can give rise to variations that are within the range for each species: a finch with a beak a little bigger than before, or a cow that yields more milk. . . . What it does not mean is that genetic variation is capable of explaining . . . entirely novel characteristics. It does not explain the appearance of a wing where before there was only an arm.
RICHARD MILTON, SHATTERING THE MYTHS OF DARWINISM
A: Why then were no ancestors ever found for the creatures of the famous Cambrian explosion 500 million years ago? The strata under the Cambrian are almost empty of animal fossils; we just can’t find the forerunners of starfish, octopus, sea urchin, clams, or snails, only bacteria, worms, and primitive organisms like algae. The story is the same for flowering plants and chordates (the precursor of vertebrates), which appeared suddenly, not to mention sudden new species at the Triassic-Jurassic boundary.
POE: Perhaps the mutation rate was upped by something like cosmic rays or a vast change in world ecology. But as for the absence of pre-Cambrian fossils, that is because they were extremely tiny and soft bodied, no skeletons.
A: All right, but what about such important and abrupt human milestones as Homo erectus, Cro-Magnon man, and Neanderthal? Didn’t H. erectus appear suddenly because hybridized? Isn’t it the same for Neanderthal? Sudden, because a hybrid? Keith, who said Europe’s Neanderthals appeared suddenly, also saw in Australia a “sudden transition from one type of mankind to another,” not due to any transformation, but because a new type of man simply appeared.
Homo erectus seems to have appeared almost abruptly.
WILLIAM HOWELLS, GETTING HERE
And why the quickening of pace as the stages of evolution proceed? Does it make sense that simple species took millions of years to evolve
but H. sapiens, the most advanced, managed in only a few thousand years? Doesn’t that bother you?
POE: No, we must only suppose that in some cases evolution has proceeded at a faster pace for reasons yet to be discovered.
A: Well, what about the rapid jump from australopith’s tiny brain (500 cc) to H. erectus’s 800 to 1,100 cc? This is evolutionarily inconceivable.
POE: Homo habilis is the missing link here; he had a distinctly bigger brain than Australopithecus. But this does not necessarily mean it happened gradually. Evolution in the Homo lineage may not have been gradual at all. Within a relatively brief period, man acquired the modern brain, pointing to surprisingly rapid development.
A: Sir Arthur Keith asked: How could the extraordinarily complex human brain have expanded in the relatively brief course of the Pleistocene? How, he asked, could the brain of Pithecanthropus (Homo erectus) “have evolved into the modern human form? I cannot credit such a rapid rate of evolution.”9 Bottom line: the way to account for this is crossbreeding with a more advanced type; after all, there is no increase in H. erectus cranial capacity (after the initial 50 percent increase from Au) during the next half million years: it stayed around 1,000 cc, until they were upgraded by crossbreeding with the mods in their midst.
POE: Have you seen the reports on Au. sedipa? These early hominids cast serious doubt on the long-standing belief that brains evolved gradually; rather, Au. sedipa’s brain must have increased in size—or rather shape—relatively quickly. That happened again, circa 600,000 years ago, another spurt in brain growth, a “punctuational” event. Think also of the breakthrough in Africa about 50,000 years ago: some fortuitous mutation in the genes spurred cultural advances, some radical reorganization, a neurological change that allowed man to develop culture, sophisticated behavior—some sort of intellectually advantageous mutation promoting the fully modern mind.
Mysterious Origins of Hybrid Man Page 15
