Evolution – What the Fossils Say and Why It Matters. Donald R Prothero, Columbia University Press. Reviewed by Louette McInnes.Continue reading
Eve bites off too much
Ian Wishart is one of New Zealand’s more prominent creationists. In a recent book he takes on evolutionary biology, a task for which he seems ill-equipped.
In his latest book, Eve’s Bite (2007), Investigate magazine managing editor Ian Wishart has a chapter titled The Beagle Boys (sub-titled Darwinism’s last stand). In it he again attacks the well established edifice of organic evolution. He heads the chapter with a quote from Ann Coulter’s Godless: The Church of Liberalism, which is worthwhile reproducing here in full because it clearly reflects the key elements of Wishart’s (false) assessment of the scientific status of evolution:
Liberal’s creation myth is Charles Darwin’s theory of evolution, which is about one notch above Scientology in scientific rigor. It’s a make-believe story, based on a theory that is a tautology, with no proof in the scientist’s laboratory or the fossil record – and that’s after 150 years of very determined looking. We wouldn’t still be talking about it but for the fact that liberals think evolution disproves God.
Are Ann Coulter and Ian Wishart right? Is evolution a myth based on a tautology (the theory of natural selection)? Does evolution lack proof in the laboratory or in the fossil record? Does it disprove God?
The theory of natural selection (defined as “survival of the fittest”), claim anti-evolutionists, is a tautology because it is merely saying those who are fittest are the ones that survive. However, this is not how most biologists now view the term ‘fittest’. In brief, the fittest organisms are the ones possessing heritable features that enable them to leave the most offspring in a particular environment, physical and biological. In other words, there are criteria of fitness that are independent of survival.
Much of the confusion perpetrated by anti-evolutionists emanates from a too-simplistic notion of natural selection. “Survival of the fittest” is best regarded as a shorthand for a complex process. (Incidentally, it is Herbert Spencer’s phrase, not Darwin’s, although Darwin did eventually incorporate it into later editions of the Origin.) In fact, the theory of natural selection is far from being tautologous. For example, it can lead to testable hypotheses (predictions) relating to particular traits. As one evolutionist, Jason Rosenhouse, has observed, “there is nothing tautological about saying…that moths possessing dark coloration will be less visible than light colored moths to predatory birds when resting on dark-colored trees.” If the theory of natural selection is a mere tautology, supplementary testable hypotheses such as this one would be non-existent. Most importantly, regardless of how evolution has occurred, the evidence for it is overwhelming.
Evidence for the process, derived from laboratory observations and experiments, emanates from several fields of research, such as comparative anatomy (from an examination of fossil and extant organisms), embryology, molecular biology and genetics.
As for the fossil record, it is a treasure trove of evidence that evolution has occurred. Not only does it reveal morphological and other details of numerous creatures from the past, it also shows an overall pattern of similarity pointing to the reality of descent with modification. In addition, numerous transitional forms have been discovered (see below).
Does evolution disprove God? It is important to realise, in the current context, that biologists in doing science are practising methodological naturalism, so that supernatural explanations, because they are empirically non-testable, can have no role to play in science; they are scientifically worthless. Therefore the accusation by anti-evolutionists that evolutionists are deliberately atheistic (that in promoting evolution they are intentionally promoting atheism) is unwarranted. In fact, not all evolutionists are atheists.
It comes as no surprise, given her take on evolution, that Coulter, a lawyer and a conservative columnist, has drawn on what she calls “the generous tutoring” of intelligent design (ID) luminaries, Michael Behe, David Berlinski and William Dembski. If she genuinely wishes to learn something about evolution, the last people she should seek help from are ID proponents. In quoting Coulter, Wishart has set the tone and the level of argument of his chapter attacking evolution.
Wishart has adopted a familiar strategy used by anti-evolutionists in general – quoting eminent scientists purporting to be demonstrating that evolution itself is in crisis. It’s not, of course, but let’s see how he tries to convince his readers that it is, and that intelligent design is the only logical successor to an apparently discredited scientific theory.
But first, a point of clarification. It is necessary to distinguish between Darwin’s theory of descent with modification, establishing the reality of the process, and his theory of natural selection. The distinction is important because, almost invariably, scientists are quoted by anti-evolutionists questioning aspects of theories relating to the mechanism(s) of evolution. But it suits Wishart (and others) to convey the impression that evolution itself is in serious doubt in scientific circles (hence his subheading: “Darwinism’s last stand”).
A passage by Niles Eldridge (American Museum of Natural History), a prominent opponent of ID creationism, extracted from his 1995 book, Reinventing Darwin (p. 95), according to Wishart, is supposed to demonstrate “the lack of fossil support” for evolution. It reads in part as follows:
No wonder paleontologists shied away from evolution for so long. It never seems to happen. Assiduous collecting yields…the very slight accumulation of change-over millions of years, at a rate too slow to really account for all the prodigious change that has occurred in evolutionary history. When we do see the introduction of evolutionary novelty, it usually shows up with a bang, and often with no firm evidence that the organisms did not evolve elsewhere! Yet that’s how the fossil record has struck many a forlorn paleontologist looking to learn something about evolution.
On the face of it, pretty damning comment surely? To understand what really concerns Eldridge we need to consider the above passage in context. It appears in a chapter devoted to a discussion of the Eldridge/Gould concept of punctuated equilibria which, as Eldridge himself describes it, “is a melding, in essence, of the pattern of stasis [as revealed in the fossil record] with the recognition that most evolutionary change seems bound up with the origin of new species-the process of speciation.” By ‘stasis’ is meant the tendency for species not to change very much, often over millions of years. Long periods of stasis (or stability) are punctuated by shorter periods of comparatively rapid change, the process of speciation. Because of its somewhat short duration (geologically speaking) in small populations on the outskirts of an ancestral species’ range, the chance of recording a speciation ‘event’ in the record of the rocks is substantially reduced.
Two points to note here. Eldridge is not denying the reality of evolutionary change-that new species and groups arise over time through the influence, essentially, of natural selection. What Eldridge and Gould have brought to the attention of fellow evolutionists is that it is possible to reconcile what palaeontologists have observed in the fossil record, in Eldridge’s words “its gappiness, and uncertainties about where its fossilized animals and plants might have come from”, with how species originate over time. This reconciliatory theory brings into question the view of gradual (imperceptible) change over eons of time in the production of new species. Most importantly, the theory of punctuated equilibria is very much concerned with rates of change, the tempo of evolution.
To repeat, what it does not bring into question is the reality of evolution itself. This is not the place, nor is it necessary, to discuss the merits or otherwise of punctuated equilibria theory or of phyletic gradualism. What the theory has done (going back to Eldredge’s statement quoted above) is show that palaeontologists do have a role to play in the elucidation of the mechanisms and patterns of evolutionary change. And we should not overlook the role long played by palaeontologists in the discovery and painstaking excavation and preparation of numerous fossils that have provided such a rich lode of evidence for the ‘fact’ of evolution.
Which brings us to Wishart’s take on the subject of transitional fossils as evidence for evolution. There aren’t any, he contends, among the 250,000 fossil species now identified and catalogued: “Nowhere, are there fossils that show a weasel-cat, or a deer-giraffe, or any other of the alleged half-breed species said to have existed. In fact, a search of the literature on giraffe evolution has failed to find a single example of a short-necked giraffe at all. The long ones just suddenly appeared.”
Let’s briefly examine each of these examples. First the ‘weasel-cat’. Weasels and cats belong to different families within the mammalian Order Carnivora (Mustelidae and Felidae respectively). Should we expect these two families to be linked by a transitional ‘weasel-cat’? Well, no. The fossil and morphological evidence together point to separate ancestral groups among the earlier carnivores. What about a deer-giraffe link? Such a link between the Cervidae and Giraffidae is conceivable, but the inter-relationships of these two families are not firmly established. The apparent absence of such a link in the fossil record does not, of course, rule out a possible future discovery.
Is Wishart correct? Is there no example of a short-necked giraffe fossil? Here Wishart really comes to grief. He couldn’t have searched very far. Here is what Prothero (New Scientist, 1 March 2008) has to say: “Most fossil giraffes looked more like the short-necked okapi, a shy white-and-brown-striped denizen of the African rain forests, and the only other living giraffid.” More recently, a fossil giraffe has been described from the late Miocene and early Pliocene. “Its neck is a perfect intermediate between the short-neck ancestors and their long-neck descendants.”
Wishart somewhat sarcastically refers to “half-breeds”. However, “half-breed” is best regarded as an offensive term pertaining to a person whose parents are of different ‘races’. The term has nothing whatever to do with transitional or intermediate forms. In fact, the fossil record contains numerous examples of transitional forms, between species and between higher groups.
Before we leave the subject of transitional fossils, a brief word about whale evolution. Wishart continues to ignore the impressive fossil evidence-a series of forms beginning with a semi-aquatic predator (Pakicetus), probably derived from the hippo-pig lineage of artiodactyls, and ending with modern whales.
The Cambrian Explosion
He again raises what is colloquially called the Cambrian explosion. The Cambrian period saw the first appearance in the fossil record of many of the major phyla of multi-cellular animals. Naturally, creationists like to take ‘explosion’ literally, depicting this period as a time of sudden or instant creation, and hence supporting the creationist scenario. (The fact that many groups preceded them, and many have arisen subsequently, seems not to concern them!) It was nothing of the sort. In brief, new groups appeared in the Cambrian over tens of millions of years. One of the chief reasons for the variety of new fossils during this period is clearly the arrival of hard-shelled invertebrates conducive to fossilisation.
There are many more examples of misconceptions and distortions about evolution in Wishart’s chapter, too numerous to expose here. The key message to take away from this critique: if you decide to read Ian Wishart or Ann Coulter on evolution, or any other ID proponent on the same subject, keep a salt cellar handy!
For previous critiques of Ian Wishart on evolution, see NZ Skeptic, winter 2002; summer 2003.
Recommended additional reading: Donald R. Prothero (2007). Evolution. What the Fossils Say and Why It Matters. Columbia University Press, New York.
Dream triggers: of shapely rocks and shapes in rocks
Research scientist Hamish Campbell spoke of his experiences as Te Papas museum geologist at the 2005 NZ Skeptics conference.Continue reading
Noah’s ark tests negative
A New Zealanders quest to find Noah’s Ark has suffered a double blow, with two samples he gathered in Turkey turning out to be rock, not petrified timber. Ross Patterson delivered the samples to crown research institute Geological and Nuclear Sciences (GNS) in Wellington. Senior geologist Hamish Campbell, who examined the samples, said they were not wood or fossil material, but volcanic rock. One of the samples had “a lovely platey fabric” and Dr Campbell said he could see why Mr Patterson thought they might be fossil wood. “I’m all for somebody chasing something like this — it makes life interesting. GNS offers a service and we are very happy to sample rock in this way.”Continue reading
Peter Lange mentions in his review a common creationist claim — the lack of intermediate fossil forms. Someone whose name I’ve lost, recently wrote the following on sci.skeptic about the subject:
We have fossil records of transitional forms out the wazoo [i.e., there are lots of them – translator]. The reason that this fact hardly causes a creationist neuron to fire is that they play a little game with an unfalsifiability engine, sometimes called Gish’s Law.
It goes a little bit like this:
E: A evolved into B.
C: Hah! There is no transitional form between A and B.
E: Sure there is. It’s called A1.
C: Hah! There is no transitional form between A and A1.
E: Sure there is. It’s called A1a.
C: Hah! There is no transitional form between A and A1a.
and so on.
There are three termination conditions to this game:
- The subdivision goes on to the point where, by random chance, there is no corresponding form in the fossil record. The creationist wins.
- The subdivision goes on to the point where the two forms being compared are close enough for the creationist to decide that they are the same “kind”. The creationist wins.
- The evolutionist decides that the creationist is an insufferable blithering idiot and gives up. The creationist wins.