Stephen E. Jones

Creation/Evolution Articles

Colin Patterson's address to the American Museum of Natural History, New York City, 1981, pages 6-10:

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SECOND PARABLE

Now I'd like to go on to the second parable and return again to this same diagram but I'd like you now to think of the way in which it was previously used by Ernst Mayr in his 1969 book with his 1974 paper on "Systematics." At that time it looked like this:

15%
10%
70%

Now, that's how Mayr tried to put some precision into evolutionary systematics. Then he said, "Let A be the common ancestor of BCD and suppose the genome of B is diverged from the ancestral genome by l5%, that of C diverged by 10%, and D has moved off rapidly into some new adaptive zone diverged by 70%." Then he said we should be quite wrong to classify C with D which appears towards its nearest relative by common ancestry because relationship means inferred amount of shared genotype not the inferred recency of common ancestry. Here is the very simple sum:

B and C share 75% of the ancestral genotype
C and D share only 30%

..... show the kind of mistakes that might be made, Mayr said that systematists might group crocodiles with birds rather than other reptiles or might group African ape with man rather than with the orangutan. So Mayr in his knowledge of evolution is making predictions about the genotype of crocodiles and African apes.

In the first example crocodiles, birds, and reptiles, he predicts that the proportion of genotypes shared by C, the crocodile and B, another reptile be greater than proportion shared by C, the crocodile and D, the bird. He predicts that in some shared genotypes BC will be greater than CD.

Now next is Mayr ..... demonstrating the explanatory power here of a hypothesis of common ancestry, something that I've [said] scarcely had zero explanatory power. He is also demonstrating a knowledge of evolution, writes a theory, makes a prediction and is going to test it.

Last month in Ann Arbor, a student of Morris Goodman gave me the amino acid sequences for alpha and beta hemoglobin of 3 crocodilians: a caiman, a Nile crocodile the Mississippi alligator. We already knew the alpha and beta hemoglobin sequences of 2 birds, a chicken and a goose but the problem is finding another reptile. As far as I know the only other reptile available at the moment is the alpha hemoglobin sequence of a snake, the viper. Alpha hemoglobin is 143 amino acids long so there 3 times that or 429 nucleotides long. That is a very small part of the genotype but at least it is worth checking. The prediction is that the amino acids common to B the viper, C the crocodile and D the chicken, that BC would be greater than CD. And here of course are his findings:

(Patterson C., "Evolutionism and Creationism," Transcript of Address at the American Museum of Natural History, New York NY, November 5, 1981, p.6) [Top of page]

Here we are. The theory makes a prediction, we've tested it and the prediction is falsified precisely. CD far outweighs BC so something is wrong with the prediction. Something is wrong with the theory. But, of course, we know that falsification is never absolute, for you're never sure what it is you have falsified.

And here we see only three possibilities. First, we've falsified the data; there is something wrong with alpha hemoglobin. Second, we've falsified the diagram; there is something wrong about the physical relationships of the snake, bird and crocodile. And third, we've falsified Mayr's knowledge of evolution, either the particular stuff about rates and adaptive zones or something more general.

We can check one of those pieces of data by taking another sample of the genome: a crocodile, bird including chicken and two other reptiles a lizard and turtle. Myoglobin is 153 amino acids long.

This time the BC proportion of the genotype is larger than the CD, slightly larger, as Mayr predicted. What happened here? What fits BD? It ought to be by far the smallest proportion of the genome, yet it is exactly the same as the BC. Something has gone wrong again. Again there are 3 possibilities: data, diagram or the theory

In fact, when you think about the diagram and this data but yet a different diagram BC same as BD, and possibility of dichotomy, like that. Perhaps the diagram is wrong.

Let's check again with the turtle, turtle myoglobin. B is the turtle (terrapin as I remember), C is crocodile and D is chicken.

Now we're getting closer to what Mayr expected. BC is much larger than BD here. Again there is another problem. The BD portion (turtle-bird) should be tiny [but] is larger than the CD. Again, something is wrong. This data suggests a different diagram like this where BC go together, D is separate.

So it seems with these three examples, either we get the right diagram as we did with the first sample .... with the viper and alpha hemoglobin but we had the wrong proportion, or we get the right proportions as here but the wrong diagram or we get a set of data that is just agnostic that gives us a trichotomy. So what is it we are falsifying? There aren't any more lizard sequences available, no more reptile sequences.

Two things we might do: One is to accept Mayr's assumption that reptiles are a group and to sum up the data and take averages. You add together 3 kinds of beings: the turtle, viper or the lizard; 3 kinds of crocodiles; 3 kinds of chickens - when you do that, the 3 summations are for BC you get 27.9, for CD you get 30.9 and BD 26.9. They are virtually identical...

(Patterson C., "Evolutionism and Creationism," Transcript of Address at the American Museum of Natural History, New York NY, November 5, 1981, p.7) [Top of page]

The creationist makes one assumption - that there are some groups in a set of data. The evolutionist, I think, has to make another assumption - that there some groups in there and that the groupings tell us something about the history of groups.

Someone from audience says: "Which creationist?"

Patterson: "Alright, me."

Audience member: "You don't mean Duane Gish?'

Patterson: "No, I don't. I mean a creationist systematist."

Audience member: "Duane Gish doesn't make any assumptions."

Other member: "Oh, yes he does."

Patterson continues lecture

I think I am able to treat that DNA .... data, taking all of it as saying something, but I only find two signals in it. In order to get a tree out of it, you have to infer that some of it is good data - the stuff that gives you that (at board) and some of at is bad data - the stuff that gives you that (at board). Sounds like [in] this case the stuff that gives you BC and AB is more than twice as numerous as the stuff that gives you BC is inferred. Now what is it that is being paired here? These are all identities at the nucleotide level, the ones that gives you AB are identities. The ones that give you .... - they are all identities at the nucleotide level. Yet somehow you'll have to say that some of those identities are ...... the same. Some of them are not the same, because the theory demands that. It seems to me somehow nonsensical.

There is one more problem with homology at the DNA level and that is this business of plurality, or inferred duplication. There is a similar problem coming in beside ...A. A couple of weeks ago Roger Lewin had a piece in Science (Oct. 23, 1981) on globin genes and in it he touched on a model of DNA that is now factual among molecular geneticists. He called it the "Vesuvian" model and a simple description of it by Roger Lewin and others is that every gene is constantly bombarding the rest of the genome with pseudogenes which are more or less perfect copies of itself. Now if this is so, and the model does have empirical support, then the problem of plurality of duplication of DNA is even more pressing.

In order to do DNA sequencing, you mix up the genome and clothe [clone?] a bit that you think is right that you can get out. If there really are all these bombarding pseudogenes lying, around I see no possible way of knowing whether you've got the right one or not.

Well, I'm sorry to have on so long about that and the point of it is that I think it has something to say about evolution because of all the discussion in the last few years whether evolution is tastable, and by evolution here I mean the general theory, the descent with modification, that species are mutable and related by descent rather than a specific theory about mechanisms.

If the general theory of evolution is testable, it must have some function ...... that can be confronted with reality. In other words, it must make

(Patterson C., "Evolutionism and Creationism," Transcript of Address at the American Museum of Natural History, New York NY, November 5, 1981, p.8) [Top of page]

some predictions. As far as I know only one sensible prediction has been offered. Niles Eldredge put it like this in a letter to Science.

"If evolution is descent with modification, the hierarchical array of organisms defined by nested sets of evolutionary novelties must result. This is evolution's grand prediction."

Then Niles went on to say that whatever organism you look at, whatever aspect of it you study, you find the same hierarchy. I've heard this same point made repeatedly, at meetings. There really is a hierarchy and there can be no hierarchy without history and therefore the prediction of evolution is met.

The first thing that strikes me about this is that it seeps [steps?] inside of evolution as a deductive inference from the systematic hierarchy. The people like Cuvier, Linneus, Hooker and a thousand other pre- Darwinians were merely fore- thinkers but they failed to see the necessary...

The second thing concerns the prediction of whatever aspect of organisms you look at, you find the same hierarchy. Not everyone wants to agree with that. Here's Ernst Mayr again in Science. Different types of characters: morphological characters, chromosomal differences, enzyme genes, regulating genes, and DNA matching made these a rather different groupings. Different stages in life cycles result in different groupings.

Here's Arnold ...... with the conclusion of his cladistic study of apes and men. His study denotes a clear lack of congruence between molecular and other more traditional kinds of data. Notice they are both saying the same. Mayr is saying that molecular data or whatever level you look at it, it doesn't seem to matter, morphology and Arnold are saying the same thing.

Now, the prediction. of evolution, according to Niles is that hierarchy and congruent hierarchy is what we'll find no matter what aspect of the species you look at. ...... the experience of Mayr and Arnold that there is no such thing as congruence. In particular, molecular data are incongruent with morphology.

Well, is that so? I'm not sure but I think there are other signs of it among protein sequences. For example, that cladogram that I was building up earlier is one of the congruents with everything that we know about morphology. Now there are published cladograms that have bird with sister group of mammals, Nile crocodiles, snakes and sister groups of all other amniotes. Never mind the details of it.

Let me put the question at the most basic level. How is it you recognize a hierarchy? At the level of the phenotype I think you have no real problem. We have a fairly rational concept of homology and I agree with Gary that the organizing principle is ontogeny and Von Baer's* law in particular. And as Gary suggested we can analyze phenotypification that way and get a hierarchy by a method that has no evolutionary implication at all. There is a history ahead but the history is on the genetics. The history is a what gives you the direction in Von Baer's law. We don't have to infer anything more about the geological [genealogical?] history, for example.

So what about this molecular level or the level of protein and DNA sequences? How do we recognize a hierarchy there? First of all, the concept of homology is

* Note: the original has "Conbear's"

(Patterson C., "Evolutionism and Creationism," Transcript of Address at the American Museum of Natural History, New York NY, November 5, 1981, p.9) [Top of page]

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