The Origins of Animal Body Plans and Their Fossil RecordsEditor’s note: ENV is delighted to present in two parts Jonathan Wells’s account of the memorable 1999 International Symposium on the Origins of Animal Body Plans and Their Fossil Records, Kunming, China, the subject of recent Internet chatter. This is part two. Find part one here.

In June 1999, Paul Nelson and I flew to Kunming in southern China to attend an International Symposium on The Origins of Animal Body Plans and Their Fossil Record, held at Fuxian Lake Hot Springs Resort. According to the invitation letter, the symposium would take “an integrated, interdisciplinary approach to the study of the origin and evolution of animal body plans. The organizers encourage not only paleontologists and evolutionary biologists, but also morphologists and developmental and molecular biologists, to attend and contribute. For example, this international gathering would be an excellent opportunity to report on recent insights into the role of Hox genes in body plan formation. The presentation of a variety of theoretical perspectives is especially encouraged.”

On Sunday June 20, we all traveled by bus to the opening ceremony of the Chengjiang Field Station, a handsome new facility built near the Chengjiang fossil site to house exhibits and provide living quarters and study space for visiting scholars. Back at Fuxian Lake the next day, Australian molecular biologist Michael Denton (whose 1985 book Evolution: A Theory in Crisis4 had profoundly influenced Phillip Johnson) began the lecture part of the conference by challenging Darwinian explanations for the origin of biological forms. He argued that

the Cambrian explosion can be accounted for far more easily in terms of the now unfashionable and largely discounted typological/teleological interpretation of nature held by most of the pre-Darwinian biologists in the 19th century such as the British anatomist Richard Owen and the German embryologist Von Baer. According to this view the organic world consists of a limited set of basic forms (types) which were built into nature from the beginning.5

When Denton finished, California Institute of Technology evolutionary developmental biologist Eric H. Davidson (who was chairing the session) jumped up and said emphatically, “You’re wrong!” He proceeded to deliver a five-minute critique of Denton’s lecture, allowing only a brief reply from Denton himself. Davidson then called on University of Southern California paleontologist David J. Bottjer, who compared Denton to people in the last century who predicted that “man would never fly.” Davidson then abruptly terminated the exchange, thereby cutting ten minutes from Denton’s allotted discussion time. Davidson’s rude and biased behavior was a harbinger of things to come.

Richard McGee of Christian Leadership Ministries then presented a historical overview of issues raised by the Cambrian explosion, concluding that “it certainly appears” that “a new theory [is] necessary for the origin of phyla.”6 McGee did not mention religion, creationism, or intelligent design, and despite his affiliation the ensuing discussion was far more civil than the one following Denton’s talk.

Co-organizer Paul Chien was affiliated with the Discovery Institute, which sponsored the participation of Denton and McGee along with Nelson and me (who lectured on the last day; see below). Of the remaining twenty-eight lectures, thirteen were given by Chinese scientists, eight by Europeans, and seven by Americans (including Davidson and Bottjer).

On Tuesday June 22, we all climbed into busses and took a field trip to J.-Y. Chen’s lab and offices in Jinning — a much humbler place than the Chengjiang Field Station. On Wednesday, we returned to the lecture hall for another day of talks.

The first Wednesday talk was by Eric Davidson, who began by stating that a “basic principle of development” is “differential regulation of genes in embryonic space.” He related this to evolution with the following syllogism: “(1) The morphological form of organisms is the product of the processes of development. (2) The processes of development are programmed in gene regulatory sequences of the genome. (3) Therefore, evolutionary change in organismal form depends on change in developmental gene regulatory sequences.” He acknowledged that major developmental genes (i.e., Hox genes) are shared by many animal phyla, so differences in body plans must be due not to the gene products themselves but to how the genes are regulated. He concluded that “one thing has to be right” — the evolution of animals is a problem of the appearance of genetic regulatory systems.7

Several participants questioned Davidson on various details. Since in the course of his talk he had claimed that Hox genes are never used in the formation of larvae, but only in patterning the adult body plan, I asked him what he would make of amphibian larvae (i.e., tadpoles) in which Hox genes clearly play a role. He replied that amphibian larvae aren’t really larvae in the same sense as sea urchin larvae are larvae, and that’s why I was “confused.”

British paleontologist Nigel Hughes (a professor at the University of California at Riverside) spoke next. He argued that the fossil record is exactly as Darwin predicted, and that there really is no problematic “Cambrian explosion” because the amount of time available was probably much greater than 10 million years.8

The last talk of the day was by American biologist Nicholas D. Holland of the Scripps Institution. Holland is an evolutionary developmental biologist who knows the historical and philosophical background of thorny issues such as homology, and who has a delightful sense of humor as well. (He told of how his wife once had a technical paper rejected by a journal “because it didn’t give the right answer.”) Holland pointed out that “all homologies are hypotheses” that “in many cases” are based on no more than “a qualitative gut feeling.” He concluded that recent advances “have brought the chordate ancestor of the vertebrates into sharper focus, but the more difficult problem — namely, where did the chordate ancestor come from — remains as enigmatic as ever.”9 Paul Nelson and I enjoyed his talk immensely.

On Thursday, June 24, most participants went into Kunming to attend an annual horticultural exposition. Paul Nelson and I (and J.-Y. Chen) remained at the conference site to work on our talks for the next day. By this time, it was clear that Davidson, Bottjer and Hughes were quite hostile toward the “Discovery Institute contingent.” Davidson and Hughes were at least willing to discuss the issues, though in a dismissive manner; by contrast, Bottjer seemed determined to shun us entirely.

The morning talks on Friday were all by paleontologists. The afternoon session was the last of the conference, and it consisted of talks by J.-Y. Chen, Paul Nelson, and myself. Chen reviewed the fossil evidence and concluded (as he had in Seattle) that it pointed to “top-down” evolution, contradicting the Darwinian expectation that minor taxonomic differences should evolve into major ones. Chen argued that harmony may be as important as competition in evolution, and he also argued that as structure and function change, so must the level of information. “As paleontologists,” he said, “we study structure, not so much function and information,” and he concluded by asking, “Is life a kind of information system?”10

Paul Nelson then spoke on “generative entrenchment,” the term coined by his University of Chicago PhD director William C. Wimsatt to denote the principle that the earliest processes in embryonic development are difficult or impossible to modify without crippling or killing the organism.11 Since body plans are established very early in development, a change in body plans would require modifications in early development that are extremely unlikely to succeed. Paul criticized Eric Davidson’s previously published theory that body plan evolution may have been facilitated by embryonic “set-aside cells” that evolve free of selective constraints,12 on the grounds that such cells could not subsequently insert themselves into earlier (and more entrenched) stages of development. Paul concluded, “it is unlikely that this problem can be solved within the current neo-Darwinian framework.”13

In the ensuing discussion, Davidson ignored the issues and simply belittled Paul for lacking biological research experience. Nick Holland, who was much more collegial, pointed out that modifications in development could produce the loss of structures — a point that Paul readily conceded, while pointing out that it would not explain how organisms gain structures.

I was the last speaker. Like many of the others, I had brought transparencies to illustrate my points (the technology available at the Fuxian Lake Hot Springs Resort was rather primitive). Sensing the hostility from Bottjer, Davidson and Hughes, I prayed during Paul’s talk that God would help me to remain calm. As I got up from my seat to go to the front of the hall, my carefully ordered transparencies slipped out of my file folder and scattered all over the floor. My first thought was, “So, God, this is how you help me!” But the mishap turned out to be a blessing in disguise: The process of picking up my transparencies and putting them back in order forced me to calm down, and by the time I arrived at the podium I had lost my nervousness (though also a few minutes of my allotted time).

In my lecture I attempted to resolve a two-fold paradox caused by the widespread occurrence of similar Hox genes in different animal phyla: (1) If genes control development (as neo-Darwinism claims), how do similar genes produce different body plans? and (2) If the phyla do not share a common ancestor but originated independently (as the fossil evidence suggests), how did they acquire similar Hox genes? Concerning the first, I argued that genes do not control development, and I pointed to other factors (such as patterns maternally imprinted on egg membranes) instead. Concerning the second, I maintained that intelligent design is a reasonable explanation for the origin of Hox genes. I briefly described Bill Dembski’s explanatory filter, pointed out that the founders of modern paleontology, systematics, embryology and genetics were all design advocates, and suggested how design could promote fruitful research.14-15

As soon as I finished, Eric Davidson (sitting in the front row) began waving a piece of paper in the air, claiming loudly that he had recorded eleven factual errors in my talk. (Davidson’s melodramatic display reminded me of the story of how Senator Joe McCarthy waved a piece of paper in front of a West Virginia audience in 1950 and claimed it was a list of government employees who were members of the Communist Party.) Davidson then accused me of deceiving those in the audience who were not trained in developmental biology. I interrupted him and requested that he describe at least one of the factual errors I had allegedly made. He resisted at first, then launched into a description of some details of fruit fly development that I had passed over.

I acknowledged the correctness of his information but pointed out that in a twenty-minute talk I could not be expected to cover everything. I added that the details he described did not alter my main point — that membrane patterns in the egg precede and control gene expression. After a few minutes of arguing, I turned to the audience and explained that what they were witnessing was a scientific dispute among developmental biologists. I then told Davidson that I admired his work on regulatory genes and even felt he deserved a Nobel prize for it, but I could not understand why he thought regulatory genes were the whole story. The exchange ended abruptly when Davidson’s female traveling companion interjected that my position was not worthy of comment.

Bottjer then stood up in the rear of the hall, and in a patronizing voice explained that since “we humans” are a product of evolution it is understandable that we might sometimes see design where none exists. For example (he said), one might see scratches on the wall of a cave and think they were the product of design, when in fact they were not. I responded that archaeologists are actually very good at distinguishing human wall paintings from natural markings, so design inferences in archaeology are quite robust. Bottjer, in a stunning non sequitur, answered that we might as well admit astrology as a science.

In a concluding open discussion, Paul Nelson suggested that it might be good to air the misgivings some participants had about Discovery’s involvement in the conference. Bottjer took the opportunity to announce that “this was not a scientific conference,” and that he would not have attended if he had known that Discovery Institute representatives would be there.16 Although Bottjer had originally volunteered to help edit a volume of conference proceedings, it was clear that he was no longer willing to do so.

Before leaving the conference I had a private a conversation with a Chinese developmental biologist from Shanghai. She and I had a good laugh over Davidson’s gall in re-defining “larva” to suit his own theory and then calling me “confused” for questioning him on it. Then she told me that in China the general practice in education is to settle on an official theory and teach it to the exclusion of all others. So far, she said, this had not happened in biology. Since she (like me) was a critic of the idea that genetic programs control development, she dreaded the possibility of being forced to teach the Davidson line. She and her colleagues believed their only hope was the willingness of Western scientists to discuss competing theories and not descend into dogmatism. She said it depressed her to see at this conference how dogmatic American biologists had already become, and she pleaded poignantly with me to defend the spirit of free inquiry in science.

I must admit I was happy to leave for Hong Kong the next morning. The Chinese participants had been uniformly cordial, and some were explicitly open to intelligent design (ID). The Europeans had also been cordial, though less open to ID. Among the Americans, Nick Holland had been a delight (though he disagrees with ID), but by the time I departed none of the other Americans would even talk to me.

Hughes subsequently published a report of the conference in the journal Evolution & Development. He called the presence of individuals supported by the Discovery Institute “embarrassing for Western scientists,” and described the talks by Michael Denton, Paul Nelson and myself as “old Pallian [sic] arguments wrapped in a variety of molecular guises.” According to Hughes I had argued that Hox genes “suggest that all metazoan [animal] phyla arose independently,” but I had been “dispatched by Eric Davidson.” (Actually, as I described above, I had argued that the fossil record suggests that the phyla arose independently.) Hughes concluded that Discovery Institute “will do whatever it takes to promote their agenda, including taking advantage of Chinese scholars. Creationism is not only a specter that haunts rationality in the United States, but it is also willing to employ a little cultural imperialism if it furthers the cause.”17

In a longer report posted on the web site of the militantly pro-Darwin National Center for Science Education, Hughes again falsely claimed that I “suggested that developmental genetic evidence favors separate origins from different single-celled lineages for the major animal groups.” But (according to Hughes) my suggestion “contradicts a wealth of scientific evidence and therefore must… arise from non-scientific convictions.”18

Within a year after the conference, J.-Y. Chen broke off all communication with Paul Chien, even though they had been long-time friends. Chen was subsequently made first author on several scientific articles written with Davidson and Bottjer and published in prestigious Western journals.19-21

Cultural imperialism, indeed.


  • (4) Denton, M. Evolution: A Theory in Crisis (New York: Adler & Adler, 1985).
  • (5) This account of the conference is based on correspondence, extensive notes I made in China, and a written report I filed with Discovery Institute upon my return; it is also based on abstracts published in the conference brochure (cited below).
  • (6) McGee, R., “Chengjiang and Cambrian Research in Historical Perspective” (abstract), pp. 14-15 in Chen, J.-Y., P.K. Chien, D.J. Bottjer, G.-X. Li & F. Gao (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (Kunming, China: Early Life Research Center, 1999).
  • (7) Davidson, E.H., “Regulatory Control of Embryological Development and the Evolutionary Origin of Animals” (abstract), p. 10 in Chen, J.-Y., et al. (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (1999).
  • (8) Hughes, N.C., “Testing the Role of Developmental Constraints in the Aftermath of the Cambrian Radiation: A Case Study Using Trilobite Thoracic Segmentation” (abstract), p. 19 in Chen, J.-Y., et al. (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (1999).
  • (9) Holland, N.D., “Bringing the Chordate Ancestor of the Vertebrates into Focus: A Decade of Progress in Neontology and Paleontology” (abstract), p. 11 in Chen, J.-Y., et al. (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (1999).
  • (10) Chen, J.Y., “Top-Down Evolution and the Fossil Evidence” (abstract), pp.
    11-14 in Chen, J.-Y., et al. (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (1999).
  • (11) Wimsatt, W.C. & J.C. Schank, “Generative Entrenchment, Modularity and Evolvability: When Genic Selection meets the Whole Organism.” Available online (2009) here.
  • (12) Davidson, E.H., K.J. Peterson & R.A. Cameron, “Origin of Bilaterian Body Plans: Evolution of Developmental Regulatory Mechanisms,” Science 270 (1995): 1319-1325.
  • (13) Nelson, P.A., “Generative Entrenchment and Body Plans” (abstract), pp. 15-16 in Chen, J.-Y., et al. (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (1999).
  • (14) Wells, J., “Resolving the Paradox of Homeotic Genes in the Origin of Animal Body Plans” (abstract), p. 16 in Chen, J.-Y., et al. (editors), International Symposium: The Origins of Animal Body Plans and Their Fossil Records (1999).
  • (15) Wells, J. “Making Sense of Biology: The Evidence for Development by Design,” Touchstone 12 (July/August 1999): 51-55.
  • (16) Heeren, F., “Paleontologic Agitprop?” The Washington Times (July 24, 2000). Available online (2009) here.
  • (17) Hughes, N.C., “The rocky road to Mendel’s play,” Evolution & Development 2:2 (2000): 63-6.
  • (18) Hughes, N.C., “Creationism and the Emergence of Animals: The Original Spin,” National Center for Science Education Reports 20:5 (September-October, 2000): 16-22, 27. Available online (2009) here.
  • (19) Chen, J.-Y., D.J. Bottjer, P. Oliveri, S.Q. Dornbos,, F. Gao, S. Ruffins, H.M. Chi, C.W. Li & E.H. Davidson, “Small bilaterian fossils from 40 to 55 million years before the Cambrian,” Science 305 (2004): 218-222.
  • (20) Chen, J.-Y., D.J. Bottjer, E.H. Davidson, S.Q. Dornbos, X. Gao, Y.H. Yang, C.W. Li, G. Li, X.Q.Wang, D.C. Xian, H.J. Wu, Y.K. Hwu & P. Tafforeau, “Phosphatized polar lobe-forming embryos from the Precambrian of Southwest China” Science 312 (2006): 1644-1646.
  • (21) Chen, J.-Y., P. Oliveri, C.W. Li, G.Q. Zhou, F. Gao, J.W. Hagadorn, K.J. Peterson & E.H. Davidson, “Precambrian animal diversity: Putative phosphatized embryos from the Doushantuo formation of China,” Proceedings of the National Academy of Sciences USA 97 (2000): 4457-4462. Available online (2009) here.