Dean's World

The following is a submission by long-time Dean's World commenter Elizabeth Reid, regarding the "Intelligent Design" textbook Of Pandas and People, which has recently been the subject of a court challenge in Dover Pennsylvania. The strongest criticism of the "Intelligent Design" theorists in my view is their lack of ability to produce falsifiable predictions. Elizabeth thinks she's got an example of one such falsifiable prediction however. Will any of ID's advocates take her up on the challenge? --Dean

I should preface this by acknowledging that not everyone who is an Intelligent Design advocate would feel comfortable with all of the assertions in this book. Behe didn't seem at ease with some of it as displayed during his cross-examination in Dover, and what I'm about to describe has little bearing on his Irreducible Complexity concept.

(1) Although the authors are somewhat cagey about it, ID as presented in the book seems not only to deny that natural selection can account for today's diversity of organisms, but to deny that common descent happened at all.

"Major groups of organisms had their own origins." (pg 78)

"Intelligent design means that various forms of life began abruptly through an intelligent agency, with their distinctive features already intact--fish with fins and scales, birds with feathers, beaks and wings, etc." (pg 99-100)

This is closely linked to their assertion that while natural variation can take place within a group, which they term microevolution, natural processes cannot produce a new type or group or kind (a little shout-out to the faithful there) of animal, which they term macroevolution.

"Minor changes caused by recombination of genes and by mutation may be acted upon by natural selection to fine-tune an organism, enabling it to fit better within its ecological niche. But no amount of fine-tuning of its current body plan will produce a new body plan." (pg 14)

"If we consider the family Felidae (cats), we see many variations, from domesticated Siamese cats to African tigers. However, we can readily distinguish between them and, for, example foxes, weasels, or dogs." (pg 39)

So the assertion is that major groups of organisms are generally readily distinguishable from each other by body plan and have "their own" origins (whether this means they have no common origins at all other than what the Designer chose to reuse is left vague).

The predictive power of this assertion is marred by their failure to define 'group' or 'type' or what kind of change would qualify as the creation of a new group. In fact, they explicitly assert that a definition of group is irrelevant to the claim! Their basis for this is the fact that terms like 'order' and 'family' also do not have strict definitions in conventional science. This is true, but then again conventional biologists recognize these as terms of convenience that represent nodes of common ancestry and don't mean much more than that. If you're going to make a firm claim that descent with modification can't produce new groups, it's not falsifiable without some kind of definition of 'group' for the purpose of the claim. But I digress.

Anyway, let's take this assertion at face value - groups are groups, modification and even speciation can take place within a group, but natural processes like natural selection or selective breeding cannot produce a new type of animal or a new group. The example on page 39 seems to be saying that whatever a 'group' is, canines and felines are in different groups.

(2) Using the example of marsupials, the authors question how conventional biologists interpret homology through the lens of natural selection. Several pages are devoted to similarities between some marsupial animals and their placental counterparts:

"For instance, in skeletal structure, the North American wolf and the now-extinct Tasmanian wolf are very close--in some features, nearly indistinguishable. [...] The marsupial wolf is strikingly similar to the placental wolf in most features, yet it is like the kangaroo in one significant feature. Upon which similarity do we build our classification scheme?" (pg 29)

"Recall the puzzle of the marsupials. According to Darwinian theory, the pattern for wolves, cats, squirrels, ground hogs, anteaters, moles, and mice each evolved twice: once in placental mammals and again, totally independently, in marsupials. This amounts to the astonishing claim that a random, undirected process of mutation and natural selection somehow hit upon identical features in widely separated organisms." (pg 33)

"In [the ID] view, the possession of similar structures implies nothing of evolutionary ancestry." (pg 33)

Again, the facts of this could be questioned (marsupial cats don't strike me as really all that catlike, nor wombats all that groundhog-like) but let's go with it. They're saying that it's only the mistaken assumptions of evolution that make us consider the marsupial method of reproduction a more important marker for taxonomy than the many other features of marsupial and placental animals. Why not use the common sense approach, which would say mice are mice, wolves are wolves?

Integrating this with #1, if each basic group originated (somewhat?) independently and the 'marsupial' grouping is meaningless, then it seems fairly clear that Tasmanian wolves should be classed with the dog-wolf 'group' given its obvious and striking similarities.

(3) Genetic and biochemical similarities between 'related' species are explained from an intelligent design perspective as being unremarkable, indeed expected.

"The classification system that emerges from molecular biology to a large extent confirms classifications traditionally made by taxonomists from anatomy. That is, a horse is more like a cow than it is like a bird not only in obvious appearance by also in the sequence of amino acids of its proteins, and of triplets in its DNA." (pg 35)

"Proponents of intelligent design read similarity in structure as a reflection of similarity in function." (pg 36)

Now for the prediction. It seems to effortlessly follow from the above that genetic comparisons between marsupial and placental mammals of the same 'group' would show them to be more similar than comparisons between the mammals and their alleged relatives under the conventional interpretation. Marsupial wolves ought to be more like placental wolves than marsupial cats and vice versa. So, if they want to prove their point, they should check. If it's not possible to do this test with the existing DNA from Tasmanian wolves, I'd be happy to see it done with any other placental mammal and its marsupial counterpart, as compared to some closely-related but structurally dissimilar control (ocelots, the cat usually mentioned as being most similar to marsupial cats, compared to both marsupial cats and placental wolves would be fine).

Finding out that Tasmanian wolves have a higher degree of genetic similarity to placental wolves than to other marsupials would utterly shake up the whole idea of common descent, so this would be a huge thing. Anyone who's wondering how to shake up my convictions about the correctness of evolutionary theory, this would absolutely do it.