The problem with the so-called "Cambrian explosion" is that many basic different body plans of animals appeared relatively instantaneously - in geologic time - about 600 million years ago. This is exactly the opposite of Darwinism's prediction of gradual development of life forms.
I quote here from "Darwin on Trial", a very well written book by Philip Johnson published in 1991 that has significantly raised people's awareness of the problems of Darwinism.
The single greatest problem which the fossil record poses for Darwinism is the "Cambrian explosion" of around 600 million years ago. Nearly all the animal phyla appear in the rocks of this period, without a trace of the evolutionary ancestors that Darwinists require. As Richard Dawkins [a staunch advocate of Darwinism] puts it, "It is as though they were just planted there, without any evolutionary history." In Darwin's time there was no evidence for the existence of pre-Cambrian life, and he conceded in "The Origin of Species" that "The case at present must remain inexplicable, and may be truly urged as a valid argument against the views here entertained." If his theory was true, Darwin wrote, the pre-Cambrian would must have "swarmed with living creatures."
In recent years evidence of bacteria and algae has been found in some of the earth's oldest rocks, and it is generally accepted today that these single-celled forms of life may have first appeared as long ago as four billion years. ... And then dozens of independent groups of multicellular animals appeared without any visible process of evolutionary development. Darwinist theory requires that there have been very lengthy sets of intermediate forms between unicellular organisms and animals like insects, worms, and clams. The evidence that these existed is missing, however, and with no good excuse.
The problem posed by the Cambrian explosion has become known to many contemporary readers due to the success of Gould's book "Wonderful Life". ...
The general picture of animal history is thus a burst of general body plans followed by extinction. No new phyla evolved thereafter. Many species exist today which are absent from the rocks of the remote past, but these all fit within general taxonomic categories present at the outset. The picture is one of evolution of a sort, but only within the confines of basic categories which themselves show no previous evolutionary history. Gould described the reclassification of the Burgess fossils as the "death knell of the artifact theory." [the theory proposed by Darwin that it is only an accident of the record that the evidence is so bad.] ...
An orthodox Darwinist would answer that a direct leap from unicellular organisms to 25 to 50 complex animal phyla without a long succession of transitional intermediates is not the sort of thing for which a plausible genetic mechanism exists, to put it mildly. Gould is describing something he calls "evolution," but the picture is so different from what Darwin and his successors had in mind that perhaps a different term ought to be found. The Darwinian model of evolution is what Gould calls the "cone of increasing diversity." This means that the story of multicellular animal life should begin with a small number of species evolving from simple forms. The dozens of different basic body plans manifest in the Cambrian fossils would then be the product of a long and gradual process of evolution from less differentiated beginnings. Nor should the cone have stopped expanding abruptly after the Cambrian explosion. If the disconfirming facts were not already known, any Darwinist would be confident that the hundreds of millions of years of post-Cambrian evolution would have produced many new phyla. [But none were produced.]
Instead we see the basic body plans all appearing first, many of these becoming extinct, and further diversification proceeding strictly with the boundaries of the original phyla. These original Cambrian groups have no visible evolutionary history, and the "artifact theory" which should supply such a history has to be discarded. Maybe a few evolutionary intermediates existed for some of the groups, although none have been conclusively identified, but otherwise just about all we have between complex mulicellular animals and single cells is some words like "fast-transition." We can call this thoroughly un-Darwinian scenario "evolution," but we are just attaching a label to a mystery.
Sudden appearance and stasis of species in the fossil record is the opposite of what Darwinian theory would predict. (pp 54-56)
Gould's book "Wonderful Life", mentioned above, studies the Cambrian period from the "Burgess Shale in Canada that gives the best fossil record of the Cambrian period up to that time. In doing just a little research on the Cambrian period on the internet, I came across this information on a yet better and more recent fossil record of that period, the Chengjiang site. This site is "much older than the Burgess Shale and the preservation of the specimens is much much finer."
The following interview is between "Real Issue", a Christian outlet, and Dr. Paul Chien, now a Christian due to his findings and who has changed his career in biology to further study this issue. Dr. Paul Chien was born in China and graduated from university in Hong Kong where he earned degrees in chemistry and botany. He completed his doctorate at the University of California, Irvine, and his post-doc at Cal Tech in marine biology. Presently he is the chairman of the biology department at the University of San Francisco.
Chien recently accepted a unique invitation to travel to China to study the fossils at the Chengjiang site. What Chien found 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.
Real Issue: 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 [the earlier portion 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.
Notice Chien's conclusion "all represented at the very beginning." It is also interesting that Gould calls this a "reverse cone of diversity". The complete opposite of what Darwin proposed.
This article was written by Reed Carson - founder of BlavatskyNet and Theosophy Foundation of Georgia