As a High-School Biology student in New Zealand, I am not required to know anything about embryology. And so, for the most part, I don’t. In the circumstances it seems that I am far from the only one.
Brian Thomas’ latest article on the Institute for Creation Research’s Daily (pseudo)Science Updates page is called Evolutionary Paradox: Embryos Resist Tinkering. From my experience over the last few months, Mr Thomas has two main ‘arguments’ on the subject of embryology: The first is that DNA is somehow not enough to explain the processes involved – for example in The Theory of Supernatural Embryology?, More Fruit Fly Larvae and the earlier Amber and Embryos – and that all mutations in the instructions for embryo development are lethal or close to – such as in Genetic Stop Sign Halts Evolutionary Explanations. This latest post belongs with the latter. Snails are related this time, rather than being entirely Drosophila related as is more usual, hence the following picture:
Where do I start? For reasons unknown, this article struck a (dis)chord with me, hence the title of this post. In the circumstances, then, the beginning it is.
What steps are required to build a snail? Can natural selection, as described by evolutionary biologists, accomplish any of these steps? These questions were investigated in a recent report by Biola University science philosopher Paul Nelson. His observations clearly show that natural selection is totally inadequate to the task.
Paul Nelson is privileged enough to have a wikipedia page that has ‘(creationist)’ appended to its title. It could be argued that, as a fellow of the Discovery Institute, that should be ‘(intelligent design advocate)’ in line with Jonathan Wells and other such people who also have other ‘famous’ people with the same name, except that he is a Young Earth Creationist, unlike most of the “Disco tute” but like the ICR. And he’s a “science philosopher“. While Intelligent Design is arguably a topic suitable for discussion in that field, he’s as much of an embryologist as I am. Biola University for it’s part is described by WP as “a private, evangelical Christian, liberal arts university located near Los Angeles.” Take from that what you will.
And if natural selection couldn’t build a snail, it couldn’t build any other animal.
Technically that doesn’t follow, but you get his point, no? Let’s see if he can prove his assertion.
Dr. Nelson’s analysis was presented at the Society for Developmental Biology Annual Meeting on July 24.1 He began by reiterating the three essential components that natural selection supposedly needs in order to function, as described in the classic 1986 book Natural Selection in the Wild by population biologist John Endler:
- First, organisms must have trait differences.
- Second, they must leave more offspring with one version of a trait than those with a different version.
- Third, they must transmit the trait versions faithfully each generation.
Nelson asked whether or not these conditions were met in the history of animals such as snails.
The Society for Developmental Biology is, at least, perfectly legitimate. What appears to have happened is that Dr Nelson presented a poster at the meeting on this subject in a hour-and-a-half timeslot concurrently with literally hundreds of other people doing the same thing, although not on the same topic, obviously. Doing that kind of thing and then hyping it after the event seems to be becoming a trend amongst creationists lately, in the circumstances.
Enough with the ad-hominem set up! What’s his point?
As you can see from the bullet list, Dr Nelson is trying to shoot down evolution by attacking the conditions that natural selection needs to work. File under “unnecessary cdesign proponentsists type counter-argument” the fact that evolution, in the form of genetic drift rather than pure natural selection, does not need the second ‘condition’.
His poster presentation described why evolution’s required changes to animal embryos are not possible. When biologists or mutations alter genes or other DNA sequences that are used during embryonic development, the result is catastrophic. In other words, experiments have proven that generating trait variations in animal embryos—which must happen for evolution to build a new life form from an old one—kills the developing animal.2 This means that the first condition for natural selection, trait variations, cannot be met in core embryonic traits.
Cite 2 here is to – you guessed it! – Genetic Stop Sign Halts Evolutionary Explanations, which I have already covered. The point he is trying to make is that Dr Nelson managed to take out the first one – in that all mutations are “catastrophic,” and therefore there can be no variation with regards to embryo development for natural selection to work with (this also cuts out genetic drift, as it can’t drift in such a circumstance).
Now this makes an actual prediction, rare amongst the creationist “literature.” If there can be no variation when it comes to the traits involved in development, careful observation should show that there is no existing variation. Something for the Institute for Creation Research should work on, no?
Now, I would argue that this has probably already been falsified. One candidate for this is the study used in More Fruit Fly Larvae, which is on the subject of a study on the genetic differences that cause one species of the Drosophila fruit-fly genus, D. melanogaster to have hairy larvae, while D. sechellia does not. What was found was that individual mutations required were pretty subtle in effect – as Mr Thomas himself admits, “only subtle DNA changes are needed to produce relevant body alterations” – but perfectly plausible. Nobody is arguing that a large proportion of mutations on the genes that control embryo development aren’t harmful, but they aren’t all. There is (usually) a path, and where there isn’t we don’t find an animal at the end of it.
“There is no evidence that the process of natural selection caused the origin of primary embryonic characters in the Bilateria [a category that includes most animals],” according to Nelson’s critique.3 And if an organism could not have evolved, it had to have been created.
Every new generation of animal is built by an unalterably precise sequence of specified events that could only have been constructed by an intelligent Person. And that Person could only be the God of the Bible.
I always find it funny when creationists declare that if evolution as we currently understand it didn’t happen, the only alternative is creationism, and also when the creator can only be their god. What about aliens? The Discovery Institute is (usually) deliberately vague in that direction for a reason.
In short, if Dr Nelson wants to have any chance of proving his claim, he needs to test if variation does, in fact, exist among animal embryos, in the same way that hair colour, say, varies due to genetics in humans. If it can be found – which is more than likely, I should think – then his claim is falsified there and then. If not, then there might be something to this. But I doubt it.
Cite 1 in Mr Thomas’ article is to the program for the conference, while #3 is to the pdf for Dr Nelson’s poster. I could critique the “critique” beyond what I have already done (which is the stuff that Mr Thomas covered) but I wont through lack of time. For example, Dr Nelson seems to make the incorrect straw man that each and every stage of an embryos development is equivalent to a stage in the animals evolution, which is patently incorrect. I could go on.