Darwin’s Doubt – Chapter 2 – Part 4
Once again we delve into the mysteries of the Cambrian and Meyer’s interpretation of it. The piece we’re talking about begins on page 31.
Meyer makes a curious statement. He will “use these conventional categories of classification” instead of phylogenetic classification. He is going to stick with the Linnean system. He does this because it’s good for his argument.
Here’s the thing. Phylogenetics ties names to clades, which are groups consisting of an ancestor and all it’s descendants. This can be a trivial task or an impossible one. For example, every scottish fold cat on the planet can be traced to the first cat with folded ears, who was named Susie, who was born in Scotland circa 1961. Susie and all of her descendants are a clade (a very tiny one). But it’s easily traceable.
It’s nearly impossible to do for fossils. We have no idea what specific organism resulted in any other specific organism. But we can look at trends in anatomy and physiology. For example, in phylogenetics, all birds are a subset of dinosaurs. They are a special case of reptile. Just like the president is a special case of US citizen.
The Linnean system is fine, as far as it goes. But we (and Meyer) must remember that it’s a completely made up system. Everything above species is totally arbitrary, based on a type (which is an individual organism) and a diagnosis (which is a statement that tells the unique characters of the type differing from other groups). In the Linnean system, birds and reptiles have the same rank… they are both classes. But, again, phylogenetically, members of aves are specialized reptiles.
Meyer talks about how the phylum is the highest grouping of organisms within each kingdom and is based on some unique feature that is represented throughout the group. Like all chordates have a notocord in at least part of their life cycle.
I explain why, in detail, that the sudden appearance of a phylum isn’t important here. Short version is that the only thing that happens is the evolution of new species. Because only new species are formed, occasionally one will form that has a unique trait… maybe a pre-notocord. Finally, an organism existed with a notocord AND was fossilized.
To the simple-minded researcher, this would appear as if an organism with a noto-cord popped out of no where. Of course, it didn’t. That would require magic which has never been shown to exist. What this shows is that the organism with a notocord (or pre-notocord) was successful and many, many offspring. Phylogenetically, we (meaning all vertebrates) are in a clade with that organism.
The concept of a phyla is completely artificial and no amount of exclamations that phyla ‘appeared’ in the Cambrian will change that.
On page 32, Meyer claims that using the phylogenetic approach “does not minimize the mystery of the Cambrian explosion”. He’s wrong, because there’s no real mystery.
Meyer is taking a made-up categorization scheme and trying to use it describe some great mystery of how the universe works.
Meyer, instead of discussing this claim properly, puts it in a large endnote. Neither the claim in the main text, nor the endnote contain any references. Even though Meyer states he talked to a “proponent of the rank-free approach” and quotes the person, we have no idea who the person is.
His endnote is almost amusing in a way. There’s something of a joke among people who have been dealing with creationists for a while. I can’t say if it actually happened, but I think it possible.
A creationist is saying that there are no transitional fossils between two groups of organisms. His opponent says, yes there is and whips out a paper describing an intermediate between the two groups. “Ah ha!” the creationist exclaims. “Now you have two missing transitionals!”
I’m not going to type out the entire argument here. But it is 100% a matter of semantics. This unknown researcher (hey, at least I actually exist), asks why aren’t clams and squid their own phyla instead of both being molluscs? Why? Because no one has made a case for it and had it accepted yet.
Yes, it really is that simple. I hate to harp on this constantly, but the base cause of this entire “mystery” is that things like phyla are completely made up. If this unknown researcher thinks that there is a case for squid to be their own phyla, then he needs to write it up, submit it, and see if it becomes accepted. If so, then we have a new phyla. That’s actually how it works.
I’ve been struggling to come up with an analogy that is both reasonable and accurate to the mistakes that Meyer makes in this regard. The best that I can come up with is the creation of the modern-fantasy novels. Most fantasy novels have been set on other worlds or way in the past of this world. But some authors wondered how cool would it be to live in this world AND have magic and fairies and dragons and vampires. The best of this (IMO) is Jim Butcher: The Dresden Files. So we created a new category: the modern fantasy.
This ‘sudden appearance’ of phyla is exactly the same thing. It’s an artifact of the fossil record and how the concept of taxonomy works. That’s all.