Michael Denton’s new book is out, Evolution: Still A Theory In Crisis.
Denton’s stance is for structuralism and against functionalism, especially as functionalism appears in it’s current form as the modern synthesis or neo-Darwinism (the cumulative selection of small adaptive changes).
Denton argues for the reality of the types, that “there are unique taxon-defining novelties not led up to gradually from some antecedent form” and that the lack of intermediates undermines the Darwinian account of evolution. He also argues that a great deal of organic order appears to be non-adaptive, including “a great number of the taxa-defining Bauplans,” and that this also undermines the Darwinian account of evolution. Evo-devo is also showing us that “Darwinian selection is not the only or even the main factor that determined the shape and main branches of the great tree of life.”
These arguments are first set forth in Chapters 3 through 5 of the book and then defended throughout the subsequent chapters.
Denton provides a list of some of the Type-Defining Homologs:
The Pentadactyl Limb
The Insect Body Plan
The Amniotic Membrane
It is not just the major taxa which are characterized by unique defining homologs or novelties:
Even individual species are often defined by unique novelties (autapomorphies in cladist terminology).
To head off a lot of irrelevant objections and nonsense from people who can’t be bothered to read the book, Denton accepts common descent and doesn’t appeal to “goddidit” as a better explanation.
- If types exist, what does that mean for Darwinian evolution?
- Does the existence of non-adaptive order undermine Darwinism?
- Does anyone think neo-Darwinism is even relevant to modern evolutionary theory?
That is entertaining, and one of the reasons we are all here, but it’s hardly a test of the correctness of evolution.
Sal is implementing the Gish Gallop, asking scatter gun questions in hopes if he shoots them out fast enough, one of them will be missed in rebuttal.
Of course, science isn’t decided or advanced on the internet, and some questions take decades to answer, sometimes centuries.
Not sure which particular claim you mean, but I don’t think large-scale history is really susceptible to direct experiment. It’s inferred. But the inference made by the ‘conventional’ evolutionary theory is that recent common ancestors and recent origins are two completely different things. I see acceptance of that as a major sticking point.
Sigh. OK, I’ll start.
1. MRCA off most species will be indicated to be relatively recent (around 10 million years or less) even using flawed (too slow) molecular clocks published by evolutionary biologists
Now I ask you, since you’ve been reading right along – WHICH MRCA is he talking about? Could it be the MRCA of some unspecified gene (there are about 30,000 gene MRCAs in the human genome)? Or is he talking about a population which branched sometime in the past? You understand, I hope, that any species has MANY common ancestors, even if we’re dealing with populations. Humans have a MRCA with chimps, the two together have a MRCA with gorillas, those three together have a MRCA with gibbons, etc. So what, exactly, is Sal talking about?
And I hope you also note that, absent any definition of what he means, his subsequent questions are not meaningful. His second “prediction” is that different clocks will tick at different rates. But this is not a prediction, this is an observation. And every clock is regarded by evolutionary biologists as having a margin of error of perhaps several orders of magnitude – pretty lousy “clock”.
Next, note that he continues to refer to THE MRCA. We still don’t know what this means.
Finally, it’s important to note that he is careful NOT to say what his predictions (whatever they mean) are intended in support of. Just for the sake of illustration, let’s say we arbitrarily pick some specific MRCA, and let’s say we average out all the various estimates of when that branch took place, and let’s say we get a (perhaps meaningless) number of 10mya. Now, so what? Let’s say we pick a dozen or two MRCAs of any species, do the same averaging, and get a range of 5-300mya. Again, so what?
I’m going to bet that something like this has already been done. Is Sal contesting anything like that? Or is he (rather incoherently) simply regurgitating the results of research with which he’s not familiar? Or what?
The way I read it, Salvador believes every extant species has a most recent common ancestor of that species.
I don’t know where he gets the 10 million year figure though.
Wouldn’t the MRCA’s of most extant species have been the original pairs on Noah’s Ark? It’s this lack of coherence, if not outright contradiction, that most leads me to reject his YEC views.
The ark fable, while entertaining to two-year-olds, is really kind of silly for adults. I doubt ANY “population” of two individuals could survive, because the gene pool would be way too small. Not to mention the thousand and one other thigh-slapping absurdities of that particular tall tale.
But if Sal is in fact talking about an ancestral population that split into two or more populations, I don’t think the historical data exist. For example, we have far better than average fossil evidence of the hominin clade, but we still don’t know how many species ever existed since the common ancestor with chimps, much less which of them belong to which lineages, or how many branchings might have taken place, either in our lineage or any other. We have only a hazy idea of the degree of gene flow between humans, Neandertals, and Denisovans, for example. We don’t know whether those were different species, or whether they vanished by interbreeding or losing a competition.
So would Sal be talking about the most recent ancestral population of two CURRENT species? I think it goes without saying that every extant species has a most recent common ancestor, even if we have no idea what that ancestor was. As someone wrote, if you do a genealogy of your ancestry and find holes, that doesn’t mean those people never existed, only that they left no record you can find.
If you are saying that his drive to find recent origins of all species has a religious motivation, I can only agree.
I can’t find any religious motivation for his figure of 10 million years.
But what do molecular clocks have to do with how long an extant species has been in existence? Salvador seems to be conflating the common ancestor of two or more lineages with the common ancestor of a single species.
We’ve all tried to argue with his points, but he ignores the answers. Nor has Sal so far been willing to admit that he’s trying to support YEC, even though we all know it. That makes it difficult to argue.
Sal doesn’t actually believe in 10 million years. He thinks our estimates of evolutionary rates are too low by a factor of several orders of magnitude. So to him, 10 million years is really a few thousand. You know, like Genesis.
Yes, he’s been told that many times. He never responds.
When you divide 10,000,000 by 175 (which Sal does) you are in YEC territory.
Does the 175 represent the number of arguments against YEC’ism?
I don’t understand his MRCA argument that well at this point but
but this I believe is mitochondrial DNA so the gene count is a fraction of the numbers you mention. If we could take a deeper dive into this argument that would be good.
I don’t think history is the limiter here. It is the ability to model. I don’t see why there can’t be specific experiments, but just my opinion. Let me think a little more about your point here.
Well, you understand that the mitochondrial eve was an individual woman who lived as one of a very large population of people. She certainly was not the first person of our species, she is simply the only person from whom all humans are descended by direct matrilineal descent. She is estimated to have lived sometime between 100,000 and 200,000 years ago. The larger number would place her somewhere near a branching event with whatever species shared that parent, while the smaller number would simply indicate that while there was a large number of humans, their direct matrilineal lines died out.
(And again, I hope you understand that there is nothing magical about mitochondrial DNA. As Joe Felsenstein explained, there is necessarily a MRCA for each gene, and the individuals possessing those genes lived all at different times.)
175 seems to be the multiplier by which the molecular clock is off, according to Sal. If he can get a molecular Adam and Eve for each species within a few million years, he’s got his YE, and perhaps a Flood.
That’s what it looks like. Could be misreading him.
Yes, you can model in very general terms. You can see how population size affects things, whether you get more or less evolution if a population goes through bottlenecks or not, whether you even need bottlenecks to have locus MRCAs, all this kind of thing. But the processes are stochastic, chaotic too, so you won’t get a repeat history in detail.
Still, an awful lot of this ought to be capable of simple descriptive understanding. Cycads for example. There is no conflict between the idea that a particular type is ancient and that species MRCAs of extant genera are recent. A simple illustration would show that: imagine we had two modern species of trilobites, close enough to place in the same genus, but no others. Would this stop trilobites from being ancient?
The main facts I’d like to get some leverage on, an understanding of from Creationists, is that a genetic locus’s MRCA !/= a bottleneck, and that species MRCAs are essentially collections of genetic locus MRCAs; they aren’t the same thing. These can certainly be well illustrated by recourse to models. But hey, I’ve fruitlessly argued geology with Byers, speciation with fifthmonarchyman and selection with phoodoo. I’m a veteran flogger of dead horses! 🙂
If train spotting can be a hobby, why not that?
I agree with your point here. This is why the scientific method is not a good match. To get a good mathematical model you need repeatability. The question in my mind is how reliable is science by inference? Sal has created an inference argument but does this have any meaning?
You can test your inferences. The distinction I draw is between a precise repeat of history in a stochastic process, and the fact that stochastic processes do have repeatable features. If, for example, one constructed various phylogenetic trees, but trees for multiple genes converged on the same tree (within limits), that is a good test of the inference that they are related. There is stochastic variation in the precise tree, but a clear signal of consistency.
You can also test Sal’s inferences. If, for example, he declared that a given range of selection coefficients would inevitably lead to extinction of any population, or that fixation cannot happen without a bottleneck, etc, it would be very easy to write models that tested the range of conditions under which this might hold. Of course, the expectation seems to be that these models should be written by his interlocutors. He’s too busy elsewhere, getting others to refute the C14 ages of coal, the impossibility of whale evolution, or some other project.