“Furthermore, we find that the fossils are distributed mostly on the terminal branches of the phylogenetic trees, but they lack mostly for the internal branches and for the nodes where they should be found according to the theory.”
Unless I’m very much mistaken, phylogenetic trees are generated by connecting organisms, living or fossil, by branches that meet at nodes. Newly discovered or analysed organisms are added as additional side branches rather than being placed on existing branches or nodes because it’s impossible to know whether a fossil species is a direct ancestor of another species. So organisms, living or fossil, will always be on the terminal branches because that’s how the algorithm works.
Anyone claiming expertise in evolutionary biology, zoology, palaeontology, cladistics or related fields should have this so deeply ingrained that voicing the above criticism is either a confession of incompetence, or a deliberate deception showing contempt for one’s audience.
You can see the criticism being made here, but I’d advocate trying to guess the profession and perhaps identity of the speaker before looking.
Yes, this is pretty hilarious. It’s very common for people unacquainted with phylogenetics to mistake cladograms for “family trees,” but it’s inexcusable for someone who thinks he’s got a well-developed critique to be that ignorant.
I haven’t clicked the link yet. Profession and identity? Hmmm. I’m going to guess Professional Swindler/Jon Wells.
EDIT: Now I’ve looked. Oh, my goodness. Even as low as my estimate of that person was, it has now fallen.
Yes. I believe the basic assumption is really just derived from the observation of the biosphere, that at any given moment there are almost always lots of similar species found all over the globe which are cousins of each other.
So if almost all of them go extinct eventually, and since only very few of them leave fossils, it’s going to be rather unlikely that you happen to get fossils from the one or few lineages that survived. So a priori the probability that any fossil species is directly ancestral to some extant species is rather low. Some of them really might be, but it’s just more reasonable to assume it probably isn’t.
So that’s how the algorithms generally work+hey’re made to put organisms on terminal branches because this is really just the most honest assessment of the likely relationships of fossils to each other and to extant life.
But a man with a long career in paleontology couldn’t find within himself the ability to recall this, to work it out, or to explain that to his audience.
Exactly. A nice example is evolution of whales, where there are all these earlier forms known only from fossils, but they are placed on side branches every time. They are meanwhile useful as proxies to the stages of evolution leading to modern whales.
The analogy is, suppose you are of German ancestry, and you are involved in an archeological dig of a bronze age grave in Germany. You uncover a skeleton. Now what are the odds that this person is one of your direct ancestors?
This goes to an issue which seems to come up all the time for me. I am often told that it is unfair to accuse creationists of dishonesty. Perhaps, it is said, they are merely mistaken, and one should always give them the benefit of the doubt.
Now, one of the things I very much doubt is whether creationists should be given the benefit of the doubt. But in cases like this, it seems downright insane to insist that this is anything other than outright dishonesty. How dim would he have to be, given his training and work, to not get this? The notion that assuming that he really is that dim is the more charitable assumption is very questionable to begin with, but even so, why would anyone ever assume such a thing?
Here you have all the ingredients. He must know that his audience is too slack-jawed and hopelessly ignorant to know the difference between a family tree and a cladogram, or to know anything at all about the concepts and methods of phylogeny. And so it is PERFECT as a lie. To anyone looking at a cladogram as a family tree, the first question that comes to mind is: “why are there no creatures anywhere in the branches? Why are they ALL at the tips?” If you’re looking to mislead, the very best practice is to exploit existing ignorance and expand it, and that’s what he does here: straight from the Liar’s Handbook.
And yet, say that these people are dishonest, and you get all this hesitancy from people who ought to know better: all this “oooh, we should never presume dishonesty.” Well, first, nobody’s presuming it; it’s the only plausible inference from compelling evidence. But, second: how the hell you do explain something like this without dishonesty? It cannot reasonably be done.
It may, somewhere and in front of some audience, be impolitic to say that the DI crew are, to the last man, a pack of outrageous, willful liars. But it is clear that this is true, and one ought never to be afraid to say what is true.
Good explanation. I’d add that in the case of very well-studied groups of fairly-recent fossils, we may be in the opposite situation. Homo ergaster in Africa, 1.5 million years ago, is very likely to actually be ancestral to later humans. There is no really viable alternative; if there was we would have found it by now, so I suspect that we shouldn’t automatically put it on the end of its own branch of the hominin tree.
A simpler assumption: we have no way of telling whether a given species is ancestral to another, so a phylogenetic algorithm should make no such assumption. So there’s always a branch separating every species from the ancestral node. However, when the algorithm estimates the lengths of branches, it’s possible for the estimated length of the branch separating a species from the ancestral node to be zero. You could, if you wanted, consider such a species to be ancestral. But there’s always uncertainty in the branch length estimate, including the possibility of unrecognized homoplasy on the tree; a reversal of character state between ancestor and descendant could leave the ancestor with an apparent autapomorphy. And of course there are also cryptic species, especially if many sorts of data that might differentiate species are unavailable, as is the case with fossils. This means it’s not possible to recognize ancestors even if you find a zero-length branch.