Dr. Paul Chien, chairman of the biology department at the University of San Francisco, recently accepted a unique invitation to travel to China to study fossils of the Cambrian era. What Chien found at the Chengjiang site, and what he has since learned about the Cambrian fauna, has changed the focus of his career. Today, Chien concentrates on further exploring and promoting the mysteries of the Cambrian explosion of life. Subsequently, Chien possesses the largest collection of Chinese Cambrian fossils in North America.
Chien attended Mere Creation, a conference last November sponsored by Christian Leadership, which was featured in the previous Real Issue. The following is an interview with Paul Chien.
RI: Dr. Chien, what is your interest in the evolution/creation debate?
Chien: Even before I became a Christian, I had doubts about evolution. During my college years I was really interested in finding answers, but I got very little help. For a while I lost interest because I thought, one way or the other, it wasn’t very important. But since I started teaching, many people ask me about that. In fact, I often speak at churches and youth groups and conferences, and I have been forced back to that question; it’s pretty much my hobby now.
RI: Until recently, you have focused on the effects of pollution on marine organisms. How then did you come to study the Cambrian “explosion of Life”?
Chien: In studying marine organisms, and mainly the invertebrate groups, I have a clear vision of the distinct characteristics of each phyla. The theory of evolution never [seemed to] apply well in my field of marine invertebrates. When the news broke concerning [the discovery of] an explosion of animal life, it really excited me because that [had been] my position for many years. Also, Phil Johnson’s chapter on fossils [Darwin on Trial, Intervarsity Press, 1991] really ignited my interest in that area.
When an opportunity came up to talk with Chinese paleontologists and to visit them and the original site of fossil discovery, it became something I had to do. So last March I organized an international group to make a visit there.
RI: So is the Chengjiang site a primary site for the Cambrian explosion?
Chien: Yes, it’s the site of the first marine animal found in the early Cambrian times we don’t count micro-organisms as animals.
RI: Are there other places in the world where you find the same organisms?
Chien: In some ways there are similarities between the China site and the other famous site, the Burgess Shale fauna in Canada. But it turns out that the China site is much older, and the preservation of the specimens is much, much finer. Even nerves, internal organs and other details can be seen that are not present in fossils in any other place.
RI: And I suppose many of these are probably soft-tissue marine-type animals?
Chien: Yes, including jellyfish-like organisms. They can even see water ducts in the jellyfish. They are all marine. That part of western China was under a shallow sea at the time.
RI: As you became more interested in this and discovered more about it, did you find it really was an “explosion of life”?
Chien: Yes. A simple way of putting it is that currently we have about 38 phyla of different groups of animals, but the total number of phyla discovered during that period of time (including those in China, Canada, and elsewhere) adds up to over 50 phyla. That means [there are] more phyla in the very, very beginning, where we found the first fossils [of animal life], than exist now.
Stephen J. Gould, [a Harvard University evolutionary biologist], has referred to this as the reverse cone of diversity. The theory of evolution implies that things get more and more complex and get more and more diverse from one single origin. But the whole thing turns out to be reversed we have more diverse groups in the very beginning, and in fact more and more of them die off over time, and we have less and less now.
RI: What information is the public hearing or not hearing about the Cambrian explosion?
Chien: The general impression people get is that we began with micro-organisms, then came lowly animals that don’t amount to much, and then came the birds, mammals and man. Scientists were looking at a very small branch of the whole animal kingdom, and they saw more complexity and advanced features in that group. But it turns out that this concept does not apply to the entire spectrum of animals or to the appearance or creation of different groups. Take all the different body plans of roundworms, flatworms, coral, jellyfish and whatever all those appeared at the very first instant.
Most textbooks will show a live tree of evolution with the groups evolving through a long period of time. If you take that tree and chop off 99 percent of it, [what is left] is closer to reality; it’s the true beginning of every group of animals, all represented at the very beginning.
Since the Cambrian period, we have only die-off and no new groups coming about, ever. There’s only one little exception cited the group known as bryozoans, which are found in the fossil record a little later. However, most people think we just haven’t found it yet; that group was probably also present in the Cambrian explosion.
Also, the animal explosion caught people’s attention when the Chinese confirmed they found a genus now called Yunnanzoon that was present in the very beginning. This genus is considered a chordate, and the phylum Chordata includes fish, mammals and man. An evolutionist would say the ancestor of humans was present then. Looked at more objectively, you could say the most complex animal group, the chordates, were represented at the beginning, and they did not go through a slow gradual evolution to become a chordate.
Someone posted an interesting documentary on Youtube about the Cambrian explosion.
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