Reply to Gibbons on Human Evolution

I had mentioned in a previous post that I was skipping William Gibbons' claims on human evolution for the time being because I was hoping that Jim Foley would weigh in with his thoughts. He has done so now and I will post it below. Jim chose not to do a line by line response, but instead to focus on the challenge he had laid out to Gibbons concerning certain specific hominid skulls. So I am posting the line by line response that I prepared, followed by Jim's response.

Human Evolution

Here Gibbons is still counting on old Lord Zuckerman to do his work for him. The problem is that Zuckerman's work was nearly 50 years ago and he lost the debate with Wilfred Le Gros Clark at the time. And as usual, Gibbons still has his facts completely wrong:

You stated that Zuckerman's work was carried out before Lucy was discovered. This is true, but you missed my point. Zuckerman's research established conclusively that the australopithecines were nothing but knuckle-walking apes, was performed on fossils that were younger than Lucy. Even if Lucy was bipedal and still adept to tree climbing, this still does not make her our ancestor, no matter how much you want an ape to be part of your family tree (pardon the pun). Although Zuckerman was an evolutionist, he never accepted the australopithecines as being directly ancestral to man. Other evolutionists did not accept his findings because he dared to put the australopithecines where they belonged - in the trees. So, my previous statement may have have been inaccurate, but it was not the "lie" you claim it to be.

Your previous statement was inaccurate and this one is scarcely any better. First, remember what he was claiming in his previous posting:

Charles Oxnard and Lord Zuckerman conducted a fifteen-year study of A. aferensis and concluded that they did not walk upright in a human manner (at least not habitually) and were certainly not our ancestors.

This is completely false. Oxnard and Zuckerman did not do a study together, their work was nearly a quarter of a century apart. And Zuckerman's work was not on A. afarensis at all, it was two decades before that species was even discovered. Zuckerman's work was on A. africanus and A. robustus, which were later species in the Australopithicene genus. As for the claim that Zuckerman's work "established conclusively that the australopithicenes were nothing but knuckle-walking apes", I can only laugh at this. It's such a standard creationist tactic to find an area where scientists had a disagreement decades ago, point to the one who supports their position and claim that they conclusively proved that the consensus is wrong, all while A) not actually citing any substantive reason why that person's views are correct, B) ignoring the fact that those views were rejected by all of their fellow scientists at the time, and C) more recent evidence confirms the consensus rather than the lone voice that the creationists are championing.

Was Zuckerman right? The evidence says no. When Zuckerman was doing his work in the early 50s, the question of whether australopithicenes were just extinct apes or were intermediate between humans and apes was still an open question. We only had two species of australopithicenes found at the time. Zuckerman's views were contrasted with the views of Wilfred Le Gros Clark, but Clark's views won the day because the evidence supported them. In particular, Clark performed a morphological study using 11 traits that distinguished between humans and apes. On all 11 traits, they were more humanlike than apelike. And when A. afarensis, an older australopithicene, was found and the study repeated using the same 11 key distinguishing traits, it falls somewhat closer to apelike, as would be expected since it was closer to apes than A. africanus and A. robustus.

On Hominid Fossils Overlapping

This is truly the place where Gibbons' argument just runs completely off the tracks. He keeps saying that if one species overlaps another in time, if they existed at the same time, then one could not possibly have evolved from the other. Folks, this is about 8th grade level biology, if that. It's total nonsense. Here is what I said in my last reply to this argument:

ED: No kidding. And this is a problem for evolution why? Of course they overlapped one another. You and your parents also overlapped one another and existed at the same time. Because creationists are so ignorant of what evolutionary theory actually says, they actually believe that an entire species turns into a new species as a group and that the ancestral species immediately ceases to exist when the new one evolves. But this is nonsense, a cartoonish caricature of evolution with no basis in reality. New species split off from already existing species, usually when they become isolated from the rest of the group by some environmental event. The reproductive isolation allows independent evolution of new traits. But the ancestral species and the daughter species both continue to exist until one or both of them become extinct. This argument is like saying that the people in Australia could not have come from England because there are still people in England. Pure stupidity.

And in his latest reply, Gibbons continues to make the same stupid claim. But this time, he's quoting another creationist making it too:

Homo erectus individuals have lived side by side with other categories of humans for the past two million years (according to evolutionist chronology). This fact eliminates the possibility that Homo erectus evolved into Homo sapiens. ...On the far end of the Homo erectus time continuum, Homo erectus is contemporary with Homo habilis for 500,000 years. In fact, Homo erectus overlaps the entire Homo habilis population.... Thus, the almost universally accepted view that Homo habilis evolved into Homo erectus becomes impossible.... Homo habilis could not be the evolutionary ancestor of Homo erectus because the two groups lived at the same time as contemporaries. (Lubenow, Marvin (1992), Bones of Contention (Grand Rapids, MI: Baker).

The fact that Lubenow is as clueless about the predominately allopatric nature of speciation as you are doesn't make the argument any less ridiculous. New species split off from already existing species; the old species does not just immediately die off the moment a new species splits off (though often at some point later the new species drives the old one to extinction through competition for resources and land, but this is typically some time later; thus, they will inevitably co-exist for at least some period of time). Again, this is not some incredibly complex piece of minutae, this is very basic evolutionary biology. If a kid in a 10th grade biology class said something this stupid on a test, he'd be flunked. But here we have our resident "PhD in creation science apologetics" demonstrating that he doesn't understand even the most basic elements of the theory he is claiming to have disproven.

Over 6,000 or so hominid fossils exist, but the problem for the evolutionist is that the majority of the fossils that make up our alleged evolutionary ancestry is fragmented with very few complete fossil remains. They were either fully humans - or they were apes. There are simply no transitions. In site of the imaginary reconstructions and alleged the "family tree" found within the textbooks, paleontologists are still divided over the exact sequence of which fossils go where.

Actually, we are blessed with something of an embarrassment of riches. We now have so many different paleo-species that overlap each other in all of the key ways that the problem is determining exactly which ancestral relationships were direct and which were evolutionary cousins or sidelines that died out. There are lots of fascinating questions in paleo-anthropology. Is Homo ergaster a separate species, or just a variation of Homo erectus? How about Homo antecessor or Homo heidelbergensis? There are now so many different fossils that all fall into the same exact pattern of development that it's mostly academic how you classify them and where exactly you draw the line between species. Because there are so many and there is so much overlapping, there will inevitably be disputes over how to classify them.

But here is what we do know for certain: there is a remarkable series of fossil species that go from the miocene primates to modern humans. If you lay these species out sequentially, you can practically watch Homo sapiens evolve. You can trace the gradual adaptation and development of all of the key diagnostic traits of humans - brain size, dentition patterns, bipedality, use of tools, signs of cultural sophistication, and so on. They appear in exactly the right anatomical and temporal sequence that evolution would predict. Let me list a few of them for you, in order, starting with the Australopithicenes:

Australopithecus afarensis: 3.9 to 3.0 million years ago. Brain size 375 to 550 cc. Bipedal, but still retained adaptations for arboreal life and more adapted for walking than for running. Canine teeth smaller than apes but larger than humans.

Australopithecus africanus: 3.0 to 2.0 million years ago. Brain size 420 to 550 cc. Bipedal, like afarensis, but the body size is larger. The teeth are more like modern humans than afarensis and the jaw structure is much more human than afarensis.

I'm skipping over the robust australopithecenes (A. robustus, A. boisei and A. aeithiopicus) because they are almost certainly not ancestral to humans and are more likely a sideline that died out.

Homo habilis: 2.4 to 1.5 million years ago. Brain size 500-800 cc, average 650. Face more human like than africanus, teeth smaller and more humanlike. Brain shape is more humanlike and there is a bulging Broca's area of the brain that suggests they were capable of rudimentary speech. Bipedal adaptation pretty much complete. Produced rudimentary stone tools.

Homo erectus: 1.8 million year to 300,000 years ago. Brain size 750 to 1225 cc, with early specimens averaging about 900 cc and later specimens averaging about 1100 cc. Dentition patterns more modern than habilis, facial structure more modern, and brain shape more modern. Stone tools were more sophisticated and there is evidence that they used fire.

Homo heidelbergensis (or archaic Homo sapiens): 500,000 to 200,000 years ago. Brain size average 1200 cc, in between erectus and modern humans. Dentition also intermediate between the two. Skeleton less robust than erectus but more robust than modern humans.

There are about a dozen more species as well that fit in between these and are probably sidelines or evolutionary cousins that died out. The pattern is so obvious that it becomes purely academic where you draw the line between species, which is why there is so much argument over specific classifications. Gibbons says that all of these were either "fully human" or "fully ape", but he doesn't tell us which is which. Creationists, in fact, have had a devil of a time deciding which ones were human and which were ape. Jim Foley has a wonderful comparison of creationist opinions on various hominid skulls that proves that this divide between apes and humans obviously isn't as wide as creationists want to pretend. Of the 6 creationists referenced, including Lubenow who is cited by Gibbons, 3 classified Peking Man (a Homo erectus specimen) as "ape" and 3 classified it as "human". They were also split 3-3 on ER-1470, a Homo habilis specimen. And split 4-2 on the Java specimens, which are also Homo erectus. Surely if all of these specimens were either "fully human" or "fully ape", they should be able to tell the difference between them easily.

More importantly, back to the same question that has thus far gone unanswered: what is the creationist explanation for this clear pattern of development? Was God practicing? Was he working his way up, making an almost-almost-human, then an almost-human, then finally a human? Did he create all these other species in just the right temporal and anatomical sequence to mimic evolution and thereby test our faith?

Jim Foley's Response

For those who don't know, Jim Foley is the man responsible for the TalkOrigins Hominids FAQ, an excellent resource for information about human evolution. This is his response to Gibbons on human evolution:

In the comments to an entry on this blog, I made the following challenge to William Gibbons:

Glad you could use some of my material, Ed. I'm disappointed that Gibson [sic] didn't choose to discuss all those 'early Homo', but not surprised because all creationists seem to develop blind spots concerning them. Mr. Gibson, please do a bit of research and come back and tell us what ER 1470, OH 24, ER 1813, ER 3733 and the Dmanisi skulls are.

Gibbons responded to my challenge later on the same page (inside a long comment which also responded to others):

The name is Gibbons, Mr. Foley. And no, creationists certainly do not have a "blind spot" concerning hominid fossils. Have you ever read Bones of Contention by Marvin L. Lubenow (Baker: 1998). However, to answer your questions: ER 1470 H. Erectus; OH 24 H. Erectus; ER 1813 Uncertain, but possibly H. Habilis; ER 3733 H. Erectus Dmanisi skulls: H. Georgicus, possibly within H.Erectus family.

Following is my detailed response to Mr. Gibbons:

The name is Gibbons, Mr. Foley.

My mistake, I fused a synapse and mixed you up with science-fiction writer William Gibson.

And no, creationists certainly do not have a "blind spot" concerning hominid fossils. Have you ever read Bones of Contention by Marvin L. Lubenow (Baker: 1998).

Sure have, many times. In fact, if you google "marvin lubenow", you'll find my review of that book near the top of the results list. By the way, I didn't say they had a blind spot with "hominid fossils", but with "early Homo".

However, to answer your questions: ER 1470 H. Erectus;

So you would you explain the anatomical differences from modern humans, some of which are listed at (just after the phrase "Although 1470 is usually placed in the genus Homo, it is definitely not a modern human").

OH 24 H. Erectus;

Have you read Lubenow's book? Because in it, on p. 164 (1992 edition) he says that OH 24, with a brain size of 590cc, is "far too small to be considered human". So what did you base that judgement on? Or was it just a guess you pulled out of your, uh, hat?

ER 1813 Uncertain, but possibly H. Habilis;

Yes, either H. habilis or something closely related. Which means, for Lubenow and I assume yourself as well, that it's an ape. And yet it looks similar to ER 1470 which you claim is erectus and human. ER 1813 is just smaller. If 1813 was 20% longer in every dimension, it would have a larger brain than ER 1470. And if I showed you unscaled photographs of both of them, I doubt you could tell me which one was the ape and which one was the human.

ER 3733 H. Erectus

Yep, it's erectus all right, which makes it human by your reckoning I assume. But look at the picture of it. Have you ever seen anyone with a shelf of bone like that sticking out above their eyes like that? (And, by the way, that's confidently thought to be the skull of a female...)

Dmanisi skulls: H. Georgicus, possibly within H.Erectus family.

I'd be fascinated to hear your anatomical justification for this. The smallest two of these skulls have brain sizes of 650cc and 600cc, and you'll recall from the Marvin Lubenow quote that you gave above that that's "far too small to be considered human". Lubenow's solution is to call the biggest one H. erectus (and hence human) and the smallest two habilis (and hence apes). But the biggest skull is very similar to the smallest two ones, far more similar to them than it is to any modern human. So answer me this: if you have a 'human' skull which resembles an 'ape' skull far more closely than it does modern human skulls, wouldn't that make it a good transitional form? And if not, why not? (Good luck getting any answers from Lubenow; as I've discussed earlier, he avoided any discussion of these fossils in the latest edition of his book.)

As for my statement about creationists having a 'blind spot' on early Homo, I'll point out that the first edition of Lubenow's book devoted about 12 pages to Homo habilis, out of about 260. Not exactly extensive coverage. And in the second edition, that dropped to less than 4 pages devoted to habilis, out of more than 330 pages of text. Homo habilis isn't even in the index. ER 1470 gets about 1.5 of those pages. There are no pictures, no descriptions of any of them. A few other habiline fossils get a couple of lines of text on them if they're lucky; most are merely mentioned in the tables of fossils. So, don't expect to run off and find answers to any of the above in Lubenow; you won't.

More like this

Once again, creationists assume that the saltationists, which were refuted by Darwin, speak for all evolutionists in asking why monkeys still exist.

Also, Gibbons' claims about Oxnard's work is incorrect. Oxnard's work found that Lucy walked upright.

One wonders why creationists don't bother to correspond with Oxnard. One wonders why they don't read his stuff.

By Ed Darrell (not verified) on 05 Sep 2005 #permalink