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.

Transitional fossils

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.

Warwick Don replies

I deny any fudging on the use of the word “creationist”. I make a clear distinction between young-earth creationism and intelligent design (ID) creationism, at the same time indicating a link between the two. In my article in Investigate magazine (November 2002), I write: “there are several types of anti-evolutionary creationists”, implying that there are also pro-evolutionary creationists. So I object to being accused of bandying the term (creationist) around.

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“Intelligent Design” in the Science Classroom

A critique of “Walking with Beasts”, by Ian Wishart, Investigate Magazine, June 2002

A Prominent English state school, Emmanuel City Technological College, has recently decided to include creationism as a viable alternative to evolution in the science classroom. In the wake of this, Ian Wishart of Investigate magazine has written an article, “Walking With Beasts”, in which he conveys the impression that the status of organic evolution is very fragile indeed. Therefore he asks: “If Darwin’s Theory of Evolution is on such shaky ground in the upper reaches of science, why are New Zealand high school students still being taught the subject without any reference to the many controversies now dogging it?”

The article is a mixture of the old and the new – arguments against evolution which have long been the province of young-earth creationism and some from the most recent version of creationism, Intelligent Design (ID) theory. ID theory has its roots in creation “science”, which probably accounts for the retention of some of the arguments associated with that movement, and in some ways it can be regarded as a more sophisticated version of its predecessor. Most significantly, when examined closely, it turns out to be the old Argument from Design in modern garb. At its core is the view that Darwinian theory is unable to account for life’s complexity – hence an Intelligent Designer must be invoked.

Sound familiar? William Paley’s watch immediately springs to mind. The only real difference between Paley and modern IDers is the incorporation of factors and processes at the biochemical and cellular levels of which Paley, of course, was unaware. Prominent names in the ID movement are Phillip Johnson (Darwin On Trial), Michael Behe (Darwin’s Black Box), Jonathan Wells (Icons of Evolution) and William Dembski (Intelligent Design: The Bridge Between Science and Theology).

A major contention of Wishart’s article is that “scientists are increasingly doubting the theory of evolution”. Unfortunately, he never really distinguishes clearly between the occurrence of evolution and its proposed mechanism, of which natural selection (Darwinism) is generally regarded as the chief agent of change. Consequently, the article switches from one aspect to the other in disconcerting fashion, such that, to the uninitiated, evolution itself appears seriously in doubt. Argument – the sign of a healthy science, not one in decline – now pertains to the “how” of the process.

The idea that evolution is on its last legs will be familiar to those conversant with creationist attacks over the years. The article repeats the hoary and long discounted argument that the fossil record lacks the expected transitional forms. “Nowhere,” writes Wishart, “are there fossils that show a cat-monkey, or a horse-giraffe, or any other of the alleged half-breed species said to have existed.” Setting aside such ludicrous caricatures, excellent examples of transitional forms between major groups do exist (see Evolution: the fossils say YES! NZ Skeptic, Summer 2001).

Somewhat ironically, Wishart sheds extreme doubt on the possibility of modern whales originating from a “carnivorous, cow-like creature about the size of a wolf … in a short period of geological time”. Apart from the “short period” amounting to at least 20 million years, the record of the rocks has revealed a fascinating series of forms, from whales with functional legs and ears like those of land mammals, to amphibious, wading and diving forms. (See Scientific American, May 2002). [Incidentally, based on new fossil evidence, the mantle of whale ancestor has shifted from the mesonychids (alluded to above) to a related group, the artiodactyls, and more specifically to the hippopotami.]

He is equally astray when he refers to “the lack of evidence for human evolution”. Apparently, he is unaware of early ape-like hominids, such as Ardipithecus ramidus, Australopithecus anamensis, and A. afarensis (“Lucy”), let alone later members of Australopithecus and early members of the genus Homo, the genus to which our species belongs. He is similarly dismissive of early bird evolution. Worth noting in this regard is a recent burst of fossil discoveries which has revealed a great diversity of Mesozoic birds; even older finds of feathered dinosaurs have corroborated prediction. Scientists await in keen anticipation further plugging of gaps in these and other transitional phases of vertebrate evolution.

Evolution well-supported

Has evolution occurred? The answer is a resounding “yes”! Darwin himself established this fact, based on an impressive consilience of evidence from several independent lines of inquiry: comparative morphology, embryology and geographical distribution, to name just a few. Since Darwin’s day, new research areas such as genetics, cell biology and molecular biology have only strengthened the level of consilience, as have many significant finds in the fossil record. Contrary to the impression continually being conveyed by anti-evolutionists, the occurrence of evolution is no longer an issue in biological science. The comparatively few scientists who seemingly question its validity are those who seem to have allowed their philosophical and religious beliefs to cloud their scientific judgment, to the extent, in some cases, of even advocating what amounts to the teaching of “theistic science”, and hence threatening the integrity of science in the classroom.

The key reason why ID and other forms of creationism must be kept out of science education is that the former have, as an inherent element, an appeal to an entity which lies outside the scope of science, whereas science deals with that part of reality amenable to empirical inquiry. Alternative explanations must be testable against the natural world. As Eugenie Scott, an American anthropologist and science educationist, has pointed out, science today is based on a necessary methodological materialism, which is not to be confused with philosophical materialism or naturalism, to which scientists and others may or may not adhere. (Wishart, to his credit, does seem to recognise the distinction between acceptance of evolution and non-scientific implications derived from it. Unfortunately, this distinction, like that between the reality of evolution and the “how” of the process, tends to become blurred in the writing.) Scott continually stresses that science neither denies nor opposes the supernatural, but ignores it for methodological reasons. She has expressed this necessary approach in colourful fashion: “You can’t put God in a test tube (or keep it out of one).” (For “God”, in the current context, read “Intelligent Designer”.)

Other points of confusion in the article are the conflation of “the origin of life” and “Big Bang theory” with organic evolution. There is a postulated continuity linking all aspects of an evolutionary universe, but each phase presents its own set of problems and requires its own specialised methodology. The conclusion that evolution has taken place, for example, rests on the evidence for it; the undoubted problems associated with the origin of the universe or with the origin of the very first life forms on this planet are irrelevant as far as organic evolution is concerned.

God of the Gaps

ID proponents tend to focus on such problem areas, which is akin to the God of the Gaps argument of earlier times. This unscientific approach is particularly apparent when a cornerstone (a very unstable one, I might add) of the ID movement is examined, namely, the idea of irreducible complexity, an idea alluded to in Wishart’s article. “By irreducibly complex”, writes Michael Behe, “I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively stop functioning”. He cites as examples of irreducible complexity, blood clotting and the movement of flagella (whiplike structures used by many microscopic organisms as swimming organelles). Such irreducibly complex structures and mechanisms, maintain IDers, could not have evolved in functional steps. The answer: intelligent design.

A Return to Paley

Setting aside the fact that reasonable naturalistic explanations do exist for many of these systems and structures (not yet satisfactorily formulated in other cases, admittedly), readers, I trust, will recognise a return to Paley in the whole idea of irreducible complexity. Drawing a line beyond which science is presumed unable to proceed is antithetical to the spirit of unfettered scientific inquiry. Is this the attitude we would wish to instil in developing and inquiring minds? And, as if this restriction were not enough, IDers would invoke some mysterious outsider as the “answer” to allegedly insoluble problems. (See the reviews of Darwin’s Black Box: Nature 383: 227-228; American Scientist 85: 474-475.)

The use of selective quotations is a favourite ploy of creationists. They are lifted from the evolutionary literature in such a way as to convey meanings not intended by their authors. In his article, Wishart provides several quotations intended to show that all is not well in evolutionary circles. Space restriction allows extended discussion of only two. However, these will serve to illustrate how misleading some selective quotations can be.

Lynn Margulis, Distinguished University Professor of Botany at the University of Massachusetts at Amhurst, is regarded in evolutionary circles as both innovator and maverick. She has been lauded for her work on cellular evolution, but her almost fanatical support of the Gaia hypothesis, considered by many scientists as unscientific, has not met with universal approval. In the article under review, several quotes by Margulis are gleaned from a profile article on her in Science 19 April 1991: 378-381. Here is how two of her statements (in italics for clarity) appear in Wishart’s article: “Darwinists, she goads, wallow in their zoological, capitalistic, competitive, cost-benefit interpretation of Darwin…Neo-Darwinism, which insists on [the slow accrual of mutation] is in a complete funk.”

The Statements in Context

Now let us consider Margulis’ first statement (in italics) in context: “Margulis defends herself and Gaia with the rhetorical verve that has long startled her colleagues. Her critics, she said in 1988, just wallow in their zoological, capitalistic, competitive, cost-benefit interpretation of Darwin – having mistaken him.” Note that Wishart makes no mention of Gaia; yet it is clearly its rejection on this occasion which particularly annoyed her and prompted this tirade. Such verbal salvoes may be grist for the creationist mill (especially when misused), but what really matters in the end is that disputes of this kind are generally resolved by the self-correcting mechanism of science.

The second statement (shown again in italics below) is preceded in the Science article with a brief discussion of Margulis’ valuable contribution to evolutionary change at the bacterial level. The writer then points out that “the controversial part of Margulis’ argument comes after that [with] her insistence that such changes could not have come through the slow buildup of chance mutations, and that therefore neo-Darwinism, which insists on that, is in a complete funk.” Addressing an audience at the University of Massachusetts, Margulis continues: “I have seen no evidence whatsoever that these changes can occur through the accumulation of gradual mutations. There’s no doubt, of course that they exist, but the major source of evolutionary novelty is the acquisition of symbionts – the whole thing then edited by natural selection. It is never just the accumulation of mutations.” [By acquisition of symbionts is meant the incorporation of free-living bacteria (e.g. mitochondria) into other bacteria to form a more complex organism.]

Original Setting Important

The above examples emphasize how vital it is to read selective quotations in creationist writings in their original setting. With reference to the second quotation, Margulis is not jettisoning natural selection entirely, merely playing down its influence as far as the production of evolutionary novelty is concerned. In this she is at odds with prominent evolutionists, a point which is stressed in the Science article. Most significantly, contrary to what might be concluded from Wishart’s article, she is not questioning evolution itself. In spite of differences with her colleagues, she is still very much an evolutionist. It is worth noting that in Wishart’s article the two quotations are linked, even though they were uttered about three years apart!

Hopeful Monsters

Wishart repeats the creationist mantra that the theory of punctuated equilibria “is similar to what became dubbed ‘the hopeful monster theory’ of the 1940s, whereby a dinosaur laid an egg and out of it hatched a bird.” This, continues Wishart, “is tantamount to admitting a miracle – divine intervention – according to creationists”. But, as Stephen Jay Gould, co-author of the punctuated equilibria theory, has observed, “the theory advances no defenses for saltational models of speciation…” (Saltation is postulated abrupt change resulting from a major mutation, that can give rise to a new class or type.)

The writer refers to the “many controversies” within evolutionary theory, which in his opinion receive curt coverage in the science curriculum. Certainly, if it is true that debate at 7th form bursary level is limited to “Darwin vs Lamarck”, then such concern is justified. However, what really concerns Wishart is revealed by the following: “Lamarck was an evolutionist like Darwin with a slightly different spin on the process. He wasn’t a Creationist.” (Emphasis added). Clearly, he wants ID creationism taught alongside evolution as an alternative explanation for biological reality.

People, of course, should be free to believe what they like, but when beliefs which are clearly non-scientific, such as the belief in an intelligent designer, are promoted as legitimate alternatives to evolution in a science curriculum, any opposition to such a move is entirely justified. It surely is the duty of educators and others genuinely concerned with the quality of science education, to resist any such intrusions and so uphold the integrity of science in the classroom.

Evolution: The Fossils Say YES!

The old creationist claim that there are no transitional forms in the fossil record is starting to look a bit tired

A perennial contention of creationists opposed to evolution is that transitions or intermediates between the major groups (classes) of vertebrates (animals with backbones) do not exist. The most persistent critic of the part played by the fossil record in providing evidence for evolution is Dr Duane Gish of the Institute for Creation Research in the United States. His arguments are expressed in two books, Evolution: The Fossils Say No! and the updated version, Evolution: The Challenge of the Fossil Record. The aim of this paper is to show that the above contention is without foundation. A classic example of a transitional form (the ancient bird, Archaeopteryx lithographica) will be examined, as well as an example of evolutionary transformation, the evolution of ear bones in vertebrates.

Discovered in 1860, one year after publication of the Origin, Archaeopteryx is of late Jurassic age. About the size of a magpie, it lived some 150 million years ago. The species is represented by seven skeletons and one isolated feather. Close examination reveals a mixture of reptilian and bird features with many more of the former than the latter. (The table below lists some of the key features). In fact, two specimens in which the feathers were not immediately recognized were initially misidentified as Compsognathus, a small bipedal dinosaur. It is often stated that if it were not for its feathers, Archaeopteryx would be classified as a small dinosaur. A transitional form between major groups is defined as a fossil which possesses a mixture (or a mosaic) of features usually associated with each of the two groups, one set ancestral (“old”), the other derived (“new”). Archaeopteryx fits the bill perfectly. Its reptilian ancestry is patently obvious.

Bird features Reptilian features
Feathers (the defining bird feature) Long bony tail
Toothed jaws
Three functional fingers with grasping claws
Feathered wings Clavicle (wishbone) boomerang-shaped as in some dinosaurs
Pelvis more reptilian in shape than in later birds
Table 1. Characteristics of Archaeopteryx

But not according to the creationists. In spite of the evidence outlined above and more fully discussed in advanced textbooks, they continue to proclaim that “a bird, is a bird, is a bird”. Thus Dr Morris: “The Archaeopteryx is a bird – not a reptile-bird transition.” And Dr Gish: “It was not a half-way bird, it was a bird”. In this regard it should be emphasized that a fossil does not have to be exactly intermediate in its features in order to be considered transitional. A mixture of definitive features, old and new, is sufficient. The period of transition between bony fish and the first amphibians, for example, is characterized by forms in which the mosaic patterns show varying rates of change of specific features in different genera.

Archaeopteryx hit the headlines a few years ago with the allegation that it was a fraud.

This assertion was made by the astronomer, Sir Fred Hoyle. He claimed that a forger had tampered with the fossilized skeleton of Compsognathus, adding impressions of feathers. This prompted scientific testing at the Museum of Natural History in London. Hoyle’s view, which must have been welcomed as grist to the anti-evolutionary mill, was proved groundless. The feather impressions were naturally formed. This early bird is still the de luxe example of a transitional form.

Now to a classic example of evolutionary transformation, a process whereby a structure becomes modified over time and changes in its primary function. Mammals almost certainly arose from a group of reptiles, aptly named the mammal-like reptiles, some 200 million years ago. The more advanced of these reptiles show trends towards the mammals in a number of features, such as improved locomotion by adopting an upright posture and differentiation of the teeth for the efficient exploitation of food sources. Palaeontologists normally are restricted to skeletal features for classifying a fossil. Soft tissues are seldom fossilized. The lower jaw or mandible in mammals is a single bone (the dentary which carries the teeth), in contrast to that of reptiles which comprises several bones. In addition, the middle ear of mammals contains three ear bones; reptiles have but one, the stapes.

The stapes can be traced to the fish stage of vertebrate evolution. (See fig. 1). The first fishes lacked true jaws. Hence many were filter feeders, extracting food from the stream of water entering the mouth and filling the pharynx. The filtered water then passed out through holes (gill slits) in the wall of the pharynx. The regions between the slits were supported by a basket of linked bones forming the branchial or gill arches. Jaws probably arose from a pair of these arches (another example of transformation). The upper element of the arch immediately behind the jaws eventually became transformed from an unspecialized part of a gill arch into a prop (the hyomandibular) to support the jaws at their region of articulation. It was thus ideally positioned, given its upper attachment to that region of the braincase which housed the organs of balance and hearing, to become a specialized sound transmitter, a potential realized later in the amphibians. The stapes (the transformed hyomandibular) greatly improved hearing on land.

The origin of the other two ear bones in mammals is even more intriguing. During the evolution of the mammal-like reptiles, the dentary bone in the lower jaw expanded greatly in order to provide greater surface area for the attachment of more powerful jaw muscles. At the same time the canines enlarged as efficient instruments for capturing and dismembering prey. Fig.2 shows the lower jaw of an advanced mammal-like reptile, Cynognathus For the sake of clarity the articular bone of the lower jaw is shown detached from the quadrate bone of the skull. In life these two bones form the jaw joint of reptiles. The expansion of the dentary involved two regions, the ascending coronoid process and the triangular articular process at the back (not to be confused with the articular bone).

In some mammal-like reptiles the articular process had grown back to the point where it touched the skull itself. This development created the potential for a new jaw joint formed by the dentary of the lower jaw and the squamosal bone of the skull. In fact, there are several examples of varying degrees of development of the “new” jaw joint, from rudimentary to fully functional, perfect examples of transitional stages, making the classification of such forms (reptile or mammal?) difficult. Should we be concerned? Not at all. Such “tricky” forms are to be expected in evolution. There is a continuity here which negates the creationist thesis of there being no transitional forms in the fossil record.

But the story is not yet over. The “new” mammalian jaw joint, once it became fully functional, rendered the “old” reptilian one superfluous. The bones of the “old” joint now relieved from a jaw articulation function were free to assume a new primary role. In this case it was not strictly a change of function but an enhancement of an existing minor function – sound transmission. The articular and quadrate bones were already somewhat inefficient conductors of sound to the inner ear in the early land vertebrates. The two bones underwent transformation to become ear bones and joined the stapes or stirrup in the middle ear to form a trio of efficient sound transmitters, greatly improving the conduction and amplification of sound waves from the outer to the inner ear. The quadrate became the incus (anvil) and the articular became the malleus (hammer). The improvement in hearing is linked to the importance of this faculty (along with smell) in promoting the survival of the first mammals as small nocturnal animals in a world dominated by large and aggressive dinosaurs.

What has Gish to say on the subject? He refers to the “unbridged gap between reptile and mammal” and questions how the “intermediates” managed to hear while the changes described above were going on. He seems to have overlooked the fact that the stapes was still present. In addition, as was pointed out above, the “old” jaw joint bones were already sound conductors. He also expresses concern as to how the animals continued to chew while the changes were in progress. But there was never a time when an “intermediate” was without functional jaws. The sequence of change with respect to jaw joints was: Old > Old + New > New.

Diarthrognathus epitomises the transition from reptile to mammal. In this animal, not only was the “old” reptilian joint between a reduced quadrate and articular present, but also a “new” and fully functional mammalian one. To cite a further example, Probainognathus also possessed a double articulation between skull and jaw. Furthermore, the quadrate bone, now only loosely joined to the rest of the skull, was intimately articulated with the stapes bone of the middle ear.

On the above evidence I rest my case. Transitional fossils between major groups of vertebrates do exist and lend powerful support to the reality of evolution.

Magician Appears

On 8 February 1994, Professor Clyde F. Herreid, Department of Biological Sciences, University of Buffalo, gave a talk in the Department of Zoology, University of Otago entitled “The Magician as Skeptic”. Notices were circulated to zoology staff and senior students, other university departments, and to local skeptics. Some 40 people thoroughly enjoyed the talk. Professor Herreid demonstrated, using a variety of magical tricks, how important it is that a natural explanation should always be sought for an apparently paranormal phenomenon. If such is not immediately forthcoming, any attempt at an explanation should be held in abeyance.