The Greatest Show on Earth

Home > Nonfiction > The Greatest Show on Earth > Page 20
The Greatest Show on Earth Page 20

by Richard Dawkins


  Hold in your head the hypothetical notion that we might, by some fluke, have been blessed with a continuous fossil record of all evolutionary change, with no links missing at all. Now look at the four Latin names that have been applied to 1470. On the face of it, the change from habilis to rudolfensis would seem to be a smaller change than the one from Australopithecus to Homo. Two species within a genus are more like each other than two genera. Aren’t they? Isn’t that the whole basis for the distinction between the genus level (say Homo or Pan as alternative genera of African apes) and the species level (say troglodytes or paniscus within the chimpanzees) in the hierarchy of classification? Well, yes, that is right when we are classifying modern animals, which can be thought of as the tips of the twigs on the evolutionary tree, with their antecedents on the inside of the tree’s crown all comfortably dead and out of the way. Naturally, those twigs that join each other further back (further into the interior of the tree’s crown) will tend to be less alike than those whose junction (more recent common ancestor) is nearer the tips. The system works, as long as we don’t try to classify the dead antecedents. But as soon as we include our hypothetically complete fossil record, all the neat separations break down. Discrete names become, as a general rule, impossible to apply. We can easily see this if we walk steadily backwards through time, much as we did with the rabbits in Chapter 2.

  As we trace the ancestry of modern Homo sapiens backwards, there must come a time when the difference from living people is sufficiently great to deserve a different specific name, say Homo ergaster. Yet, every step of the way, individuals were presumably sufficiently similar to their parents and their children to be placed in the same species. Now we go back further, tracing the ancestry of Homo ergaster, and there must come a time when we reach individuals who are sufficiently different from ‘mainstream’ ergaster to deserve a different specific name, say Homo habilis. And now we come to the point of this argument. As we go back further still, at some point we must start to hit individuals sufficiently different from modern Homo sapiens to deserve a different genus name: say Australopithecus. The trouble is, ‘sufficiently different from modern Homo sapiens’ is another matter entirely from ‘sufficiently different from the earliest Homo’, here designated Homo habilis. Think about the first specimen of Homo habilis to be born. Her parents were Australopithecus. She belonged to a different genus from her parents? That’s just dopey! Yes it certainly is. But it is not reality that’s at fault, it’s our human insistence on shoving everything into a named category. In reality, there was no such creature as the first specimen of Homo habilis. There was no first specimen of any species or any genus or any order or any class or any phylum. Every creature that has ever been born would have been classified – had there been a zoologist around to do the classifying – as belonging to exactly the same species as its parents and its children. Yet, with the hindsight of modernity, and with the benefit – yes, in this one paradoxical sense benefit – of the fact that most of the links are missing, classification into distinct species, genera, families, orders, classes and phyla becomes possible.

  I wish we really did have a complete and unbroken trail of fossils, a cinematic record of all evolutionary change as it happened. I wish it, not least because I’d love to see the egg all over the faces of those zoologists and anthropologists who engage in lifelong feuds with each other over whether such and such a fossil belongs to this species or that, this genus or that. Gentlemen – I wonder why it never seems to be ladies – you are arguing about words, not reality. As Darwin himself said, in The Descent of Man, ‘In a series of forms graduating insensibly from some apelike creature to man as he now exists, it would be impossible to fix on any definite point where the term “man” ought to be used.’

  Let’s move on through the fossils, and look at some more recent links among those that are no longer missing, although they were missing in Darwin’s time. What intermediates can we find between ourselves and the various creatures like 1470 and Twiggy, who are sometimes called Homo and sometimes called Australopithecus? We’ve already met some of them, as Java Man and Peking Man, normally classified as Homo erectus. But those two lived in Asia, and there’s good evidence that most of our human evolution took place in Africa. Java Man and Peking Man and their kind were emigrants from the mother continent of Africa. Within Africa itself, their equivalents are nowadays usually classified as Homo ergaster, although for many years they were all called Homo erectus – yet another illustration of the fickleness of our naming procedures. The most famous specimen of Homo ergaster, and one of the most complete pre-human fossils ever found, is the Turkana Boy, or Nariokotome Boy, discovered by Kamoya Kimeu, star fossil-finder of Richard Leakey’s team of palaeontologists.

  Homo erectus

  The Turkana Boy lived approximately 1.6 million years ago and died at the age of about eleven. There are indications that he would have grown to a height of 6 feet if he had lived to adulthood. His projected adult brain volume would have been about 900 cubic centimetres (cc). This was typical of Homo ergaster/erectus brains, which varied around 1,000 cc. It is significantly smaller than modern human brains, which vary around 1,300 or 1,400 cc, but larger than Homo habilis (around 600 cc) which in turn was larger than Australopithecus (around 400 cc) and chimpanzees (around the same). You’ll remember we concluded that our ancestor of three million years ago had the brain of a chimpanzee but walked on its hind legs. From this we might presume that the second half of the story, from 3 million years ago to recent times, would be a tale of increasing brain size. And so, indeed, it proves.

  Homo ergaster/erectus, of which we have many fossil specimens, is a very persuasive halfway link, no longer missing, between Homo sapiens today and Homo habilis two million years ago, which is in turn a beautiful link back to Australopithecus three million years ago, which, as we saw, could pretty well be described as an upright-walking chimpanzee. How many links do you need, before you concede that they are no longer ‘missing’? And can we also bridge the gap between Homo ergaster and modern Homo sapiens? Yes: we have a rich lode of fossils, covering the last few hundred thousand years, which are intermediate between them. Some have been given species names, like Homo heidelbergensis, Homo rhodesiensis and Homo neanderthalensis. Others (and sometimes the same ones) are called ‘archaic’ Homo sapiens. But, as I keep repeating, names don’t matter. What matters is that the links are no longer missing. Intermediates abound.

  JUST GO AND LOOK

  So, we have fine fossil documentation of gradual change, all the way from Lucy, the ‘upright-walking chimp’ of three million years ago, to ourselves today. How do history-deniers cope with this evidence? Some by literal denial. I encountered this in an interview I did for the Channel Four television documentary The Genius of Charles Darwin in 2008. I was interviewing Wendy Wright, President of ‘Concerned Women for America’. Her opinion that ‘The morning-after pill is a pedophile’s best friend’ gives a fair idea of her powers of reasoning, and she fully lived up to expectation during our interview. Only a very small part of the interview was used for the television documentary. What follows is a much fuller transcript, but obviously for the purposes of this chapter I have confined myself to those places where we discussed the fossil record of human ancestry.

  Wendy: What I go back to is the evolutionists are still lacking the science to back it up. But instead what happens is science that doesn’t bolster the case for evolution gets censored out. Such as there is no evidence of evolution from going from one species to another species. If that, if evolution had occurred then surely whether it’s going from birds to mammals or, or, even beyond that surely there’d be at least one evidence.

  Richard: There’s a massive amount of evidence. I’m sorry but you people keep repeating that like a kind of mantra because you, you, just listen to each other. I mean, if only you would just open your eyes and look at the evidence.

  Wendy: Show it to me, show me the, show me the bones, show me the carcass, show me th
e evidence of the in-between stages from one species to another.

  Richard: Every time a fossil is found which is in between one species and another you guys say, ‘Ah, now we’ve got two gaps where there, where previously there was only one.’ I mean almost every fossil you find is intermediate between something and something else.

  Wendy [laughs]: If that were the case, the Smithsonian Natural History Museum would be filled with these examples but it isn’t.

  Richard: It is, it is . . . in the case of humans, since Darwin’s time there’s now an enormous amount of evidence about intermediates in human fossils and you’ve got various species of Australopithecus for example, and . . . then you’ve got Homo habilis – these are intermediates between Australopithecus which was an older species and Homo sapiens which is a younger species. I mean, why don’t you see those as intermediates?

  Wendy: . . . if evolution has had the actual evidence then it would be displayed in museums not just in illustrations.

  Richard: I just told you about Australopithecus, Homo habilis, Homo erectus, Homo sapiens – archaic Homo sapiens and then modern Homo sapiens – that’s a beautiful series of intermediates.

  Wendy: You’re still lacking the material evidence so . . .

  Richard: The material evidence is there. Go to the museum and look at it . . . I don’t have them here obviously, but you can go to any museum and you can see Australopithecus, you can see Homo habilis, you can see Homo erectus, you can see archaic Homo sapiens and modern Homo sapiens. A beautiful series of intermediates. Why do you keep saying ‘Present me with the evidence’ when I’ve done so? Go to the museum and look.

  Wendy: And I have. I have gone to the museums and there are so many of us who still are not convinced . . .

  Richard: Have you seen, have you seen Homo erectus?

  Wendy: And I think there’s this effort, this rather aggressive effort to try and talk over us and to censor us. It seems to come out of a frustration that so many people still don’t believe in evolution. Now if evolutionists were so confident in their beliefs there wouldn’t be the effort to censor out information. It shows that evolution is still lacking and is questionable.

  Richard: I am . . . I confess to being frustrated. It’s not about suppression, it’s about the fact that I have told you about four or five fossils . . . [Wendy laughs] . . . and you seem to simply be ignoring what I’m saying . . . Why don’t you go and look at those fossils?

  Wendy: . . . If they were in the museums which I’ve been to many times, then I would look at them objectively, but what I go back to is . . .

  Richard: They are in the museum.

  Wendy: What I go back to is that the philosophy of evolution can lead to ideologies that have been so destructive to the human race . . .

  Richard: Yes, but wouldn’t it be a good idea, instead of pointing to misperceptions of Darwinism, which have been hideously misused politically, if you tried to understand Darwinism, then you’d be in a position to counteract these horrible misunderstandings.

  Wendy: Well actually we are so often forced by the aggressiveness of those who favour evolution. It’s not as if we are hidden from this information that you keep presenting. It’s not as if it is unknown to us, because we can’t get away from it. It’s pushed on us all the time. But I think your frustration comes from the fact that so many of us who have seen your information still don’t buy into your ideology.

  Richard: Have you seen Homo erectus? Have you seen Homo habilis? Have you seen Australopithecus? I’ve asked you that question.

  Wendy: What I’ve seen is that in the museums and in the textbooks whenever they claim to show the evolutionary differences from one species to another, it relies on illustrations and drawings . . . not any material evidence.

  Richard: Well, you might have to go to the Nairobi Museum to see the original fossils but you can see casts of fossils – exact copies of these fossils in any major museum you care to look at.

  Wendy: Well, let me ask you why you are so aggressive? Why is it so important to you that everyone believes like you believe?

  Richard: I’m not talking about belief, I’m talking about facts. I’ve told you about certain fossils, and every time I ask you about them you evade the question and turn to something else.

  Wendy: . . . There should be overwhelming tons of material evidence not just an isolated thing, but again, there is not evidence.

  Richard: I happened to pick hominid fossils because I thought you’d be most interested in them, but you can find similar fossils from any vertebrate group you care to name.

  Wendy: But I guess I go back to why is it so important to you that everyone believes in evolution . . .

  Richard: I don’t like the word belief. I prefer to just ask people to look at the evidence, and I’m asking you to look at the evidence . . . I want you to go to museums and look at the facts and don’t believe what you have been told that there is no evidence. Just go and look at the evidence.

  Wendy [laughs]: And yes, and what I would say . . .

  Richard: It’s not funny. I mean, really go, go. I’ve told you about hominid fossils, and you can go and see the evolution of the horse, you can go and look at the evolution of the early mammals, you can go and look at the evolution of fish, you can go and look at the transition from fish to land-living amphibians and reptiles. Any of those things you will find in any good museum. Just open your eyes and look at the facts.

  Wendy: And I would say open your eyes and see the communities that have been built by those who believe in a loving God who created each one of us . . .

  It might seem, in that exchange, that I was being needlessly obstinate in hammering home the request that she should go to a museum and look, but I really meant it. These people have been coached to say, ‘There are no fossils, show me the evidence, show me just one fossil . . .’ and they say it so often that they come to believe it. So I tried the experiment of mentioning three or four fossils to this woman and not letting her get away with simply ignoring them. The results are depressing, and a good example of the commonest tactic used by history-deniers when confronted with the evidence of history – namely, just ignore it and repeat the mantra: ‘Show me the fossils. Where are the fossils? There are no fossils. Just show me one intermediate fossil, that’s all I ask . . .’

  Others befuddle themselves with names, and the inevitable tendency names have to make false divisions where there are none. Every fossil that might potentially be intermediate is always classified as either Homo or Australopithecus. None is ever classified as intermediate. Therefore there are no intermediates. But, as I have explained above, this is an inevitable consequence of the conventions of zoological nomenclature, not a fact about the real world. The most perfect intermediate you could possibly imagine would still find itself shoehorned into either Homo or Australopithecus. In fact, it would probably be called Homo by half the palaeontologists and Australopithecus by the other half. And unfortunately, instead of getting together to agree that ambiguously intermediate fossils are exactly what we should expect on the evolution theory, the palaeontologists could probably be relied upon to give an entirely false impression by seeming almost to come to blows over their terminological disagreement.

  It’s a bit like the legal distinction between an adult and a minor. For legal purposes, and for deciding whether a young person is old enough to vote or join the army, it is necessary to make an absolute distinction. In 1969 the legal voting age in Britain was lowered from twenty-one to eighteen (in 1971 the same change was made in the USA). Now there’s talk of lowering it to sixteen. But, whatever the legal voting age may be, nobody seriously thinks the stroke of midnight on the eighteenth (or twenty-first, or sixteenth) birthday actually turns you into a different kind of person. Nobody seriously believes there are two kinds of people, children and adults, with ‘no intermediates’. Obviously we all understand that the whole period of growing up is one long exercise in intermediacy. Some of us, it might be said, have never really
grown up. Similarly, human evolution, from something like Australopithecus afarensis to Homo sapiens, consisted of an unbroken series of parents giving birth to children who would certainly have been placed, by a contemporary taxonomist, in the same species as their parents. With hindsight, and for reasons that are not far from legalistic, modern taxonomists insist on tying a label around each fossil, which must say something like Australopithecus or Homo. Museum labels are positively not allowed to say ‘halfway between Australopithecus africanus and Homo habilis’. History-deniers seize upon this naming convention as though it were evidence of a lack of intermediates in the real world. You might as well say there is no such thing as an adolescent because every single person you look at turns out to be either a voting adult (eighteen or over) or a non-voting child (under eighteen). It’s tantamount to saying that the legal necessity for a voting age threshold proves that adolescents don’t exist.

  Back to the fossils again. If the creationist apologists are right, Australopithecus is ‘just an ape’, so its own predecessors are irrelevant to the search for ‘missing links’. Nevertheless, we may as well look at them. There are a few, albeit rather fragmentary, traces. Ardipithecus, which lived 4–5 million years ago, is known mainly from teeth, but enough cranial and foot bones have been found to suggest, at least to most anatomists who have attended to it, that it walked upright. Much the same conclusion has been drawn by the respective discoverers of two even older fossils, Orrorin (‘Millennium Man’) and Sahelanthropus (‘Toumai’, below).

 

‹ Prev