Monday, 10 June 2013

Understanding God's Word through His Creation - 6

Evolution - More than "Just a Theory"

The considerable fossil evidence for human evolution is a topic many Christians prefer to pretend does not exist. Geologist and evangelical Christian Davis Young observes:
The modern evangelical church is extremely sensitive about open discussion of scientific issues that bear on Genesis 1-11. Enough Christians are so afraid of what might turn up in such discussions that anyone who does try to explore the issues is in ecclesiastical jeopardy. The prevailing atmosphere of fear tends to squelch attempts to deal with these issues. The issue of the origin of humankind is especially sensitive. It seems that the church is afraid to look into paleoanthropology. Where is the curiosity about the physical history of human beings? Among the multitude of evangelical commentaries on Genesis, hardly any of them address the problems of anthropology. Geology is often discussed. Some of the commentators have admitted the possibility of a local flood; others are not yet sure of the legitimacy of geological findings. But virtually all of the commentators assume the anthropological universality of the flood without any engagement whatsoever with the archaeological and anthropological data relevant to the question of the flood's impact on the human race. It's as if the hundreds, perhaps thousands of ancient human sites around the world didn't exist. [41]
For Christians who believe as a matter of faith that Adam and Eve were the ancestors of the entire human race and were created approximately six to ten thousand years ago, the considerable archaeological and palaeoanthropological evidence of human existence extending back to nearly 200,000 years ago is often treated by ignoring it. As Young lamented however, any attempt to understand how this evidence can be reconciled with the Genesis account, or even to mention that it exists often places the questioner in “ecclesiastical jeopardy.”

Our community unfortunately suffers from this reluctance to look into palaeoanthropology, and it is no exaggeration to say that attempts to examine Genesis in the light of this evidence have placed Christadelphians at risk of excommunication. This was precisely the fate of the English Christadelphian Ralph Lovelock who in the mid 1960s attempted to examine the implications of palaeoanthropology for the traditional reading of Genesis. After some controversy, Lovelock’s ecclesia withdrew fellowship from him, but did so realising that the issues raised could not be simply ignored:
“At the same time, we are strongly of the opinion that the problems that undoubtedly exist should be frankly admitted by us as a community, for we do naught but dishonour to the word of God by pretending that these problems are not there. Our Brotherhood bears a responsibility to those in search of Scripture truth, and especially to those of tender years, to turn its attention to the solving of these difficulties in an atmosphere of calm, sincere, conscientious study, unhindered by the rumours, mistrust, suspicion and hasty judgments that have been all too prevalent among us in recent times.” [42]
Over forty years have passed since then, and not only has the fossil evidence for human evolution increased astronomically, [43] the genomics revolution of the last twenty years has provided overwhelming evidence not only against the belief that the entire human race descended exclusively from two human beings living a few thousand years ago, but that humans and primates share a common ancestor. [44] However, not only have we not “frankly admitted” the existence of these problems, people who try to raise these issues have been subjected to abuse and ridicule by fellow believers [45] who invariably are simply not in a position to comment authoritatively on the science, but rely on creationist arguments long refuted by the scientific community. 

Those who are “of tender years” are now seeing the evidence for evolution when they enter higher education, and are not receiving the informed support from their elders. Comments such as these are representative of the unease felt by those who are confronted with the far from nebulous evidence for common descent and large scale evolutionary change:
“My own eldest son has decided he cannot be baptized because he has seen the evidence for evolution with his own eyes, and our ecclesia will not tolerate discussion on the subject. Unlike some young people, he is too honest to say he doesn’t believe it, just so that he can ‘pass the test’ and be baptized.” 
“I will be spending most of this semester studying common descent and evolution in first year biology, and have done so through DNA and cells so far. It really is fascinating and very undeniable. There's also a young Christo girl from [X ecclesia] in the subject, and I am interested to know what she's thinking.” [46]
Just as disconcerting is the fact that anti-evolutionary public lectures by prominent Christadelphian speakers have increasingly been targeted by defenders of mainstream science, with the post-mortem examinations of such confrontations placed online. In 2005, Jeffrey Shallit, a professor at the School of Computer Science at the University of Waterloo, Ontario published an open letter [47] to John Bilello, an emeritus professor of Materials Science and Engineering at the University of Michigan, after attending a public lecture by Bilello, “Darwin vs. Genesis” given in April 2005. Shallit’s professional background is in computer science and mathematics, [48] but he has been active in the evolution vs. creation debate for some time, and has co-authored a paper criticising the Intelligent Design advocate William Dembski’s “complex specified information” which is claimed to be a marker of design by intelligent agents. [49]

Shallit’s open letter is of course his view of proceedings, but in the absence of any formal rebuttal from John Bilello is the only one that will be seen by anyone who is aware of his high profile in the Christadelphian world on the evolution vs. creation debate, and is diligently searching the internet for material by him. [50] If Shallit’s letter accurately captures what was presented at the public lecture, then his less than favourable impression is unfortunately justified:
Dear Dr. John C. Bilello,
I attended part of your talk, “Darwin vs. Genesis”, at the Waterloo, Ontario Community Centre on Saturday, April 30, 2005. 
I found your talk filled with misconceptions and misrepresentations, most of which could be easily corrected by taking an undergraduate course in evolutionary biology. I know you will want to correct these mistakes in future talks.
1. You claimed that scientists do not know the mechanism of how DNA changes. This is simply false. Point mutations, for example, can be due to tautomeric shift (a movement of hydrogen atoms that changes the properties of bonding). Radiation, including ultraviolet and gamma rays, are other causes of mutations. This is taught in undergraduate biology.
2. You claimed that changes to the genome do not result in new species. Again, this is simply false. For example, new species of garden flowers are routinely created through polyploidy. For more examples of speciation events, see
3. You seem to not understand what “neo-Darwinism” is. In your talk you said that Stephen Jay Gould was one of its leading proponents, and you implied that neo-Darwinism had a close association with punctuated equilibrium. In fact, “neo-Darwinism” (also called the “Modern Synthesis”) is simply evolutionary theory as it has developed in light of modern genetics and population biology. Neo-Darwinism includes genetic drift as a mechanism of evolution. It also says that characteristics are inherited discretely, as genes. You can read more about what biologists understand by “neo-Darwinism” by reading a biology textbook, such as Futuyma’s Evolutionary Biology or by following this link:  
4. You claim that “laboratory experiments have not verified neo-Darwinism”. I don’t know what this is supposed to mean. Are you denying the gene theory of inheritance? Or that genetic drift is an evolutionary mechanism? [51]
As Shallit noted at the start of his open letter, none of these basic errors would be made by a competent undergraduate biology student. As a medical professional who is aware of the evidence for evolution just in the anatomical quirks of the human body [52] and has studied molecular biology, genetics and embryology in preparation for post-graduate specialist entry examinations, I concur with Shallit’s view. As a fellow believer, I am simply embarrassed to see poorly researched attacks on evolution made in the name of the Christadelphian community. 

John Hellawell is another retired Christadelphian scientist who has made a name for himself in commenting on the evolution vs. creation debate. [53] Unlike John Bilello, his professional background is in freshwater ecology, which puts him in a somewhat better position to speak on biological matters. However, citing any criticism of evolution he makes as authoritative simply because he is a freshwater ecologist is no more than an argument from authority. Of more importance would be to see what his publication history and professional experience is, in order to see if he has worked specifically in evolutionary biology, or whether he has made substantive criticisms of evolution that have withstood peer scrutiny. A representative sample of his publication history [54-57] shows as expected expertise in freshwater ecology. What laypeople often overlook is that outside of a scientist’s field of expertise, his knowledge may be no better than that of an undergraduate, or even an educated layperson. Furthermore, it is possible to obtain an undergraduate degree in the life sciences and not have any exposure to evolution other than that obtained in a first year introductory subject. Dennis Venema, in reflecting on his undergraduate biology studies states:
“To my delight, I found that university was not going to require me to hold my breath spiritually for four years. Soon I was involved with Inter-Varsity Christian Fellowship and enjoying the friendship of many other Christian students. Biology, however, remained boring and laundry-list like. My grades in chemistry and physics were still higher than those within my declared major of biology. The one bright spot was that evolution barely seemed to rate a mention except in passing. Certainly no compelling evidence for evolution was ever mentioned – professors seemed too intent on teaching the details of their fields to provide a wider evolutionary context. Even the introductory survey courses seemed more intent on a mere description of biodiversity rather than any detailed understanding of how that diversity arose. I did note that there was a 400-level evolution course, but thankfully it was an optional elective. Avoiding the evolution issue was easier than I had thought: I simply skipped taking that elective.” [58]
Any layperson who naively thinks that having a degree in biology automatically means that the holder of the degree understands evolutionary biology in sufficient detail to speak authoritatively on it is simply ignorant of what is actually taught in some areas of the life sciences.

As the evidence for common descent is drawn from multiple areas, anyone – scientist or layperson – who attacks this subject will be making authoritative claims in areas in which they simply cannot be speaking with authority. Representatives from the British Centre for Science Education attended “The Darwin Delusion”, a talk given by Hellawell at Reddich Town Hall in November 2009 and methodically criticised his presentation afterwards. A record of this debacle was posted at their blog, which along with Shallit’s dissection of John Bilello’s presentation in 2005 suggests strongly that anti-evolutionary lectures by Christadelphians do far more harm than good:
“The talk started with a glowing introduction to Dr Hellawell informing us how qualified a biologist he was and how the guy introducing him couldn’t even pronounce what his PhD was in. That suggested to me that those who’d invited him wouldn’t be qualified to know if he was telling the truth or not.
“He said that after 150 years, evolution is still a bone of contention within the scientific community, which is simply untrue. He also mentioned a book by John Lennox which gave evidence against evolution. Lennox is a mathematician and philosopher, not a scientist. The infamous New Scientist headline was also quoted (Darwin was wrong) without reference to the actual article or the editorial predicting is would be used in just this dishonest way by creationists.”
“When dealing with [evidence for evolution in the fossil record] he was in his element and told us how Darwin had referred to the fact we should see transitions in the fossil record and lamented the fact we didn’t.
“Here is the quote he gave;
“But, as by this theory innumerable transitional forms must have existed, why do we not find them embedded in countless numbers in the crust of the earth?”
“And here is the rest of it, that was kept from the audience by Dr Hellawell;
“It will be more convenient to discuss this question in the chapter on the Imperfection of the Geological Record; and I will here only state that I believe the answer mainly lies in the record being incomparably less perfect than is generally supposed. The crust of the earth is a vast museum; but the natural collections have been imperfectly made, and only at long intervals of time.”
“Here is an extract from the chapter Darwin refers to;
“These causes [the imperfection of the fossil record, the limited exploration of the record, poor fossilization of certain body types, etc.], taken conjointly, will to a large extent explain why -- though we do find many links -- we do not find interminable varieties, connecting together all extinct and existing forms by the finest graduated steps. It should also be constantly borne in mind that any linking variety between two forms, which might be found, would be ranked, unless the whole chain could be perfectly restored, as a new and distinct species; for it is not pretended that we have any sure criterion by which species and varieties can be discriminated.”
“I think that by anyone’s standards, simply quoting the first line is extremely dishonest and misleading.
“But Hellawell simply went on to claim that the situation had not changed since Darwin’s day.
“He repeated again and again that there were no transition fossils (untrue - and this I could and did challenge in the Q & A)  [59]
Two demonstrably false assertions by John Hellawell can be found this excerpt from the main blog entry. The first is Hellawell’s claim that evolution remains a bone of contention in the scientific community. One of course needs to point out that the term ‘evolution’ refers both to the fact of evolution, and the mechanism by which it is said to have occurred. Failing to differentiate between these two different meanings lies at the heart of a considerable amount of creationist confusion on the subject, though given that Darwin was at pains to make this difference clear, [60] there is little excuse to continue to make this error. An analogous situation exists with gravity. Currently, we do not have a complete theory of gravity as general relativity does not work at the quantum level. The fact that we do not have a quantum theory of gravity does not mean that rocks do not fall to the ground when dropped or planets do not orbit their suns. However, this is precisely the logic used by science denialists who claim that difficulties, real or imagined, in the modern synthetic theory of evolution mean that the considerable evidence for common descent and large scale evolutionary change in the fossil record and comparative genomics simply vanishes.

To put it simply, while the mechanism of evolutionary change is still an area of active research, the fact that evolution has occurred has not been disputed in the scientific world for a considerable amount of time. The genomics expert and evolutionary biologist TR Gregory notes:
In The Origin of Species, published in 1859, Darwin cited independent lines of evidence such as the biogeographical distribution of species, homology of structure, the occurrence of vestigial organs and atavisms, and the already well established process of extinction as all pointing to a conclusion that species have changed over time and are connected by descent from common ancestors. Through the force of Darwin’s argument and the mass of supporting data he presented, it was not long before the contemporary scientific community came to acknowledge the historical reality of evolutionary descent.
Over the past 150 years, this initial list has been supplemented by countless observations in paleontology, comparative anatomy, developmental biology, molecular biology, and (most recently) comparative genomics, and through direct observations of evolutionary change in both natural and experimental populations. Each of thousands of peer-reviewed articles published every year in scientific journals provides further confirmation (though, as Futuyma…notes, “no biologist today would think of publishing a paper on ‘new evidence for evolution’ ... it simply hasn’t been an issue in scientific circles for more than a century”). Conversely, no reliable observation has ever been found to contradict the general notion of common descent. It should come as no surprise, then, that the scientific community at large has accepted evolutionary descent as a historical reality since Darwin’s time and considers it among the most reliably established and fundamentally important facts in all of science. (Emphasis mine) [61]
It reflects poorly on Hellawell's grasp of evolution that he would claim that it  remains a “bone of contention” in the scientific community. The mechanism is still a subject of scientific debate. The fact of evolution is disputed by no biologist outside of a tiny fundamentalist fringe which rejects most of modern science on spurious theological grounds.

Secondly, his claim as recorded by the BSCE correspondent that there are no transitional fossils is not only incorrect, but yet another example of a scientist making unsubstantiated claims well outside his field of expertise and making embarrassingly bad mistakes in the process. John Hellawell is a freshwater ecologist, not a palaeontologist, so his opinion in this area is no more authoritative than any other educated layperson. If we look at what working palaeontologists have to say about the existence of transitional fossils, a completely different picture emerges.

Palaeontologists generally accept that birds evolved from dinosaurs, a view that dates back to Thomas Huxley in the 19th century. Luis Chiappe, from the Natural History Museum of Los Angeles County notes:
“The origin of modern birds is undoubtedly one of the most dramatic examples of an evolutionary transition—one connecting animals akin to the fearsome Tyrannosaurus rex with the feathered marvels we now see all around us—a transformation documented by a wealth of intermediate fossils that date back to the Mesozoic Era, the geologic period that spanned between 245 and 65 million years ago…A wealth of intermediate fossils has made the evolutionary saga toward modern birds one of the best documented transitions in the history of life.” [63]
“Since the 1960s, a greater understanding of small predatory dinosaurs of the Cretaceous age, such as the dromaeosaurid Deinonychus, has led to the idea that birds had originated from within a group of bird-like theropods called maniraptorans. Today, the skeletons of such maniraptoran theropods such as the sickle-clawed dromaeosaurids (Deinonychus, Velociraptor, and their kin), the lightly built troodontids (Troodon, Mei, and their kin), the parrot-headed oviraptorids (Oviraptor and relatives), and the short-armed alvarezsaurids (Mononykus and its kin) are recognized as sharing a great deal of similarity with birds. Not only have birds retained the bipedalism, hollowed bones, and the three fully developed toes of their theropod predecessors, but these animals also share a series of air spaces connected to the ear region, unique structures of their vertebral column and rib cage, elongate forelimbs with wrist bones allowing swivel-like movements of the hand and similar structures in the pelvis and hindlimbs, as well as many other characteristics distributed over the entire skeleton. Indeed, many skeletal features previously thought to be exclusively avian—such as wishbones, laterally facing wingpits, and large breastbones—have now been discovered among nonavian maniraptorans.”  [64]
“In the last few decades, our understanding of the origin and subsequent evolutionary diversification of birds has advanced at an unparalleled pace. These fossil discoveries have documented the stepwise nature of one of the most fascinating evolutionary transitions, and they have filled the large gap that separated living birds from their dinosaurian predecessors. This new evidence has shown that many of the features previously considered to be avian trademarks first evolved within theropod dinosaurs”. [65]
To this, one can add the evidence for tetrapod evolution from sarcopterygians, or lobe finned fish which is also well attested from the fossil record. In a review article, the palaeontologist Jenny Clack, one of the leading researchers in tetrapod evolution summarised the fossil evidence for tetrapod evolution, concluding:
“In summary, we now have a much richer fossil record that has improved our understanding of the timing, sequence of events, and conditions in which the origin of tetrapods took place. The boundary between “fish” and “tetrapods” is becoming progressively more difficult to draw, and a more complex story is emerging in which, for example, the origin of limbs with digits, the origin of walking and terrestriality, and the origin of tetrapods in a strict sense, may be three different things.” [66]
One of the more spectacular transition fossil discoveries in recent years was Tiktaalik roseae, a sarcoptyerygian fish intermediate between fish and tetrapod:
“A phylogenetic analysis of sarcopterygian fishes and early tetrapods supports the hypothesis that Tiktaalik is the sister group of tetrapods or shares this position with Elpistostege. Tiktaalik retains primitive tetrapodomorph features such as dorsal scale cover, paired fins with lepidotrichia, a generalized lower jaw, and separated entopterygoids in the palate, but also possesses a number of derived features of the skull, pectoral girdle and fin, and ribs that are shared with stem tetrapods such as Acanthostega and Ichthyostega.” [67]
In other words, Tiktaalik was a mosaic of lobe-finned fish and tetrapod features, exactly what one would expect of a transitional fossil. Of particular note are its forelimbs, which are intermediate between fish and tetrapod:
“The pectoral skeleton of Tiktaalik is transitional between fish fin and tetrapod limb. Comparison of the fin with those of related fish reveals that the manus is not a de novo novelty of tetrapods; rather, it was assembled in fishes over evolutionary time to meet the diverse challenges of life in the margins of Devonian aquatic ecosystems.” [68]

Tiktaalik justifiably deserves its iconic status in palaeontology as it is about as good a transitional fossil as one would hope to expect. 
Whale evolution is also another area with an embarrassment of transitional fossil riches. J.G.W. Thewissen et al (Thewissen is one of the leading experts in cetacean palaeontology) survey the current fossil record and conclude that “[in] the past two decades, the origin of whales has gone from being based on barely any fossils to one of the best documented examples of macroevolution.” [69]
Snakes fossilise poorly, yet despite this a number of transitional fossils exist, showing the existence of snakes with hind limbs. Najash rionegrina  [70] was a snake that lived approximately 90 million years ago in the late Cretaceous. It possessed a sacrum (a pelvic bone formed from fused vertebrae) as well as a pelvic girdle and functional hind limbs. Pachyrhachis problematicus  [71] is another Cretaceous snake with hind limbs and a pelvis, but does not have a sacrum. To this one can add Haasiophis terrasanctus  [72] which like Pachyrachis possesses hind limbs, but no sacrum. Snakes are believed to have evolved from reptiles with legs, so the presence of snakes with hind limbs is exactly the sort of transitional fossil one would expect to see if evolution had occurred.

Finally, the fossil record of terrestrial hoofed mammals demonstrates many key transitional forms. Donald Prothero, a vertebrate palaeontologist who specialises in mammalian palaeontology. Of tapir evolution, Prothero writes:
Closely related to rhinos are the tapirs and their kin, including the chalicotheres. We have already seen that the earliest tapiroid, Homogalax, is barely different from the earliest horse. From this ancestry, tapiroids rapidly developed the specialized molars with two strong crosscrests for chopping up their leafy diet and the retracted nasal bones that were the attachment area for their prominent proboscis. The continual transformation of their teeth and skulls can be seen throughout their evolution, so that although Homogalax bears only the tiniest resemblance to the modern tapir, it can be linked with numerous transitional fossils that show every step in their evolution. [73]
Prothero also notes that the giraffes, despite what creationists allege:
“…have an excellent fossil record, although nearly all giraffes (both extinct and living) are short-necked, much like the modern okapi. Only the living genus Giraffa has the long neck that we consider typical of the group. All the rest of the giraffids were not only short-necked but sported a wide variety of cranial appendages. Some, like Sivatherium, were stocky moose-like creatures with broad palmate horns somewhat like those of a moose. Others, like Climacoceras, looked more like deer or antelopes. Despite these superficial convergences, they all show the characteristic hallmarks of giraffids in their teeth, skulls, and skeletons.
“Most of these taxa are known from skulls and jaws and a few from skeletons, but the neck vertebrae are not often preserved. However, Nikos Solounias (2007, personal communication) is currently publishing a description of a new fossil of the giraffid Bohlinia that preserves a neck that is intermediate in length between Giraffa and the okapi. Thus, we do know how the giraffe got its long neck, and we have the transitional fossils to show how and when it occurred! Once again, the fossil record has provided a specimen whose very existence the creationists have long denied.” [74]
The following excursion into vertebrate palaeontology barely touches the surface, but should be enough to demonstrate that anyone blithely asserting that transitional fossils do not exist simply does not know what he or she is talking about. Prothero’s conclusion to his review paper is harsh, but needs to be heard by everyone who risks damaging the cause of Christ by making poorly-researched, ill-informed attacks on evolution in public:
“If they really cared to find out whether there were transitional forms in the fossil record, they would stop quoting out of context from children’s books or outdated secondary sources and obtain the proper anatomical and paleontological training to study the fossils themselves. Since they do not even bother to do this, their arguments are worthless.” [75]
Arguments against evolution in our main journals are no better than those raised in public lectures. John Morris, writing in the November 2009 edition of The Christadelphian argued that there were “many challenges to put before an evolutionist”, one of which was the assertion that “missing links are still missing.” Needless to say, any evolutionary biologist would have little difficulty dealing with that “challenge”. Morris continued by admitting:
“The trouble is, in trying to answer an ‘expert’, we can so readily be wrong-footed. Few of us have advanced qualifications in the relevant sciences, and if we fail to hold our own in discussions about fossils, for example, or if we reveal our ignorance of current molecular biology, we shall be deemed to have lost the contest! “ [76]
Morris unfortunately has completely missed the point. If we are wrong-footed by an expert, then we need to accept that they may well be right, and adjust our theology accordingly. The contrast between C.C. Walker’s open-minded attitude towards science and John Morris’ recycling of long-refuted creationist talking points is stark, and quite frankly quite depressing. It is no exaggeration to state that any young believer wanting credible information on how to reconcile science and faith with respect to evolution will be hard pressed to find anything substantive offered officially by our community. That is nothing short of scandalous. 

This article first appeared at my Facebook page here


41. Young DA “Theology and Natural Science”. Cited in Noll M “The Scandal of the Evangelical Mind” (1994, Eerdmans)

42. Statement from the Watford Ecclesia The Christadelphian (1966) 103:543

43. “Opponents of scientific biology are fond of dismissing that record as a pathetic handful of controversial fragments. If that were so, this book would be a lot shorter. An often-repeated creationist canard insists that all known human fossils would fit on a billiard table. This was probably true in the 19th century, but it has not been true for a hundred years. Known human fossils number in the thousands and represent the remains of hundreds of individuals...Having seen most of the major collections of human fossils in the world's museums, we can assure our readers that those collections can no longer be laid out on a billiard table. It would be hard to cram them into a boxcar.” – Cartmill M, Smith FH, Brown KB “The Human Lineage” xi (Wiley, 2009)

44. Venema D “Genesis and the Genome: Genomics Evidence for Human-Ape Common Ancestry and Ancestral Hominid Population SizesPSCF (2010) 62:166-178. Venema shows that the genetic diversity in the human genome could not have arisen from two human beings in a few thousands years: “Taken individually and collectively, population genomics studies strongly suggest that our lineage has not experienced an extreme population bottleneck in the last nine million years or more (and thus not in any hominid, nor even an australopithecine species), and that any bottlenecks our lineage did experience were a reduction only to a population of several thousand breeding individuals. As such, the hypothesis that humans are genetically derived from a single ancestral pair in the recent past has no support from a genomics perspective, and, indeed, is counter to a large body of evidence.” (p 175). In addition, he notes that the presence of shared identical genetic errors in exactly the same places in the genomes of related species is exactly what we would see if those species shared a common ancestor: “This pattern is precisely what common ancestry predicts for these species, since an identical mutation present in two species is most readily explained by its presence in the common ancestor of both species. The common ancestor of humans and gorillas is also the common ancestor of chimpanzees, hence inactivating mutations present in humans and gorillas are also predicted to be present in chimpanzees. In short, the existence of shared pseudogenes between primate genomes, their syntenic locations, and their patterns of inactivation and distribution all coherently support the same model of common ancestry based on comparative sequence homology criteria alone.” Venema, far from being a militant atheist is an evangelical Christian who entered university as a sceptic of evolutionary biology, only to be persuaded by the evidence for evolution as a graduate student.

45. See for example the website of David Brown, who has endured persecution for raising the subject of evolution. His experience is not isolated, unfortunately.

46. Anecdotes such as these are fairly commonly heard from Christadelphians who have entered higher education and studied the life sciences or medicine in the last decade.

47. Shallit J “An Open Letter to John C. Bilello, or More Data for the Salem HypothesisPanda’s Thumb May 4th 2005

48. There is unfortunately a long creationist tradition of professionals outside the earth or life sciences making sweeping criticisms of evolutionary biology, despite the fact that they are simply not in a position to speak authoritatively on the subject. Even when such creationist critics have a relevant background in geology or biology, the position they espouse is very much a minority opinion, and has been so for over 100 years. Furthermore, as common descent is attested by multiple converging lines of evidence from disciplines as diverse as palaeontology, ecology, molecular biology, anatomy and developmental biology, anyone who asserts that common descent is false is making the implied claim to have a detailed understanding of these areas of science, sufficient to make an authoritative claim in these domains. This needless to say is a bold claim to make, given that genuine polymaths are hardly thick on the ground. Conversely, any reasonably educated person is able to understand the main lines of evidence that demonstrate common descent and large scale evolutionary change, and summarise the consensus view. The burden of proof lies exclusively on the sceptic of evolution to make his claim, a point which many science denialists curiously find difficult to comprehend.

49. Elsberry W and Shallit J “Information theory, evolutionary computation, and Dembski’s ‘complex specified information.’” Synthese (2011) 178:237-270

50. This is precisely how I first encountered Shallit’s open letter.

51. See ref .47

52. Held L.I. “Quirks of Human Anatomy: An Evo-Devo Look at the Human Body” (2009, Cambridge University Press)

53. Hellawell J.M. “Creation or Evolution?” (2004, CMPA)

54. Hellawell J.M. “Toxic substances in rivers and streams” Environ Pollut. 1988;50(1-2):61-85.

55. Hellawell J.M., Abel R. “A rapid volumetric method for the analysis of the food of fishes” Journal of Fish Biology 1971;3(1);29-37

56. Cowx I.G, Young W.O, Hellawell J.M., “The influence of drought on the fish and invertebrate populations of an upland stream in Wales” Freshwater Biology 1984;14(2);165-177

57. Hellawell J.M. “The growth, reproduction and food of the roach Rutilus rutilus (L.), of the River Lugg, Herefordshire” Journal of Fish Biology 1972;4(4);469-486

58. Venema D “From Intelligent Design to BioLogos, Part 1: Early yearsThe BioLogos Forum 20th July 2011.

59. Belle-de-Gene “Creation Watch report from RedditchBritish Centre for Science Education 20th December 2009

60. “Some of those who admit the principle of evolution, but reject natural selection, seem to forget, when criticising my book, that I had the above two objects in view; hence if I have erred in giving to natural selection great power, which I am very far from admitting, or in having exaggerated its power, which is in itself probable, I have at least, as I hope, done good service in aiding to overthrow the dogma of separate creations.” Darwin C. The descent of man, and selection in relation to sex. (London: John Murray; 1871.)

61. Gregory T.R “Evolution as Fact, Theory and PathEvo Edu Outreach (2008) 1:46-52

62. Huxley TH On the animals which are most nearly intermediate between the birds and the reptiles. Ann Mag Nat Hist. 1868; 2:66–75.

63. Chiappe L.M. “Downsized Dinosaurs: The Evolutionary Transition to Modern BirdsEvo Edu Outreach (2009) 2:248-256.

64. ibid, p 249

65. ibid, p 256

66. Clack J.A. The Fish–Tetrapod Transition: New Fossils and Interpretations. Evo Edu Outreach (2009) 2:213-223

67. Daeschler EB, Shubin NH, Jenkins F.A. A Devonian tetrapod-like fish and the evolution of the tetrapod body plan. Nature (2006) 440:757-63.

68. Shubin NH, Daeschler EB, Jenkins F.A. The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb. Nature. (2006) 440:764-71.

69. Thewissen JGM, Cooper LN, George JC, Bajpai S. From Land to Water: the Origin of Whales, Dolphins, and Porpoises. Evo Edu Outreach. (2009) 2:272-288.

70. ApesteguĆ­a, SebastiĆ”n; Hussam Zaher “A Cretaceous terrestrial snake with robust hindlimbs and a sacrum.” Nature (2006) 440:1037–1040

71. Caldwell MW, Lee MSY. A snake with legs from the marine Cretaceous of the Middle East. Nature. (1997) 386:705-709.

72. Tchernov E, Rieppel O, Zaher H, Polcyn MJ, Jacobs LL. A fossil snake with limbs. Science (2000) 287:2010-2.

73. Prothero DR. Evolutionary Transitions in the Fossil Record of Terrestrial Hoofed Mammals. Evo Edu Outreach. (2009) 2:289-302.

74. ibid, p 297-298

75. ibid, p 302.

76. Morris J “Darwin or the Gospel?” The Christadelphian November 2009