Without gradualness... We are back to a miracle. - Richard Dawkins, Evolutionary Biologist.
Phyla are abstract categories that bring together basic features that unite large groups of animals. So you can think of a phylum as a group of organisms that all share a basic architecture. Based on the body plans of animals, we divide animals into these major groups. We have vertebrates, arthropods, echinoderms (such as sea urchins), etc. So each group has its own unique features that make them very different from the next group. The stability and consistency of the forms that make up the unique groups of phyla, contradict Darwin's vision of an interconnected tree of life. The phyla do not blend imperceptibly, one into another. So the question is; how did these differences arise? If one reads the origin of species, it is clear that Darwin is caught in a bind.
“Natura non facit saltum.” This was Darwin's famous Latin phrase which means, "nature takes no sudden leaps”. In fact, Darwin went on to say that if we found evidence of saltation, of a sudden appearance in the fossil record, that would be something equivalent to evidence of special creation.
If you can imagine creating a graph that would visualize Darwin's theory, you would see a gradually growing curve of emerging phyla body types over a long period of time. Now visualize a graph of what we've learned from the thousands of excavations throughout the globe particularly of the Cambrian and Precambrian periods. What we see is a massive spike in the number of new species during the Cambria and thereafter a few that trickle in here and there across the timeline. Alternately these two graphs are so dramatically different they visually emphasize the disparity between Darwin's theory and what the fossil record actually shows us. What we see is all the major body plans at the beginning, and the organisms and life forms we see today fit within those basic body structures. They do not gradually increase over time as would be in line with Darwin's theory.
The sudden appearance of the Cambrian body plans deepens the mystery in another way. The Darwinian model predicts that as new biological forms evolved, simple to complex, they developed gradually from the smallest differences in classification to the largest or from the “bottom up.” Darwin's idea was that, given enough time evolution would lead to new species, new families, orders and eventually phyla. Only after millions and millions of generations do you end up with the several dozen phyla that we see around us today. That is the bottom-up pattern predicted by Darwin's theory. Now the other picture is top-down. The top-down picture says the primary differences in body types are original. They are present from the start. When you find mollusks in the fossil record, there they are, and the arthropods... Boom, there they are, with the major differences present right from the beginning. So the upper level of architecture is top-down, present and right there.
The fossil record clearly shows all the known basic body plans we have today – appearing in what seems a geological instant.
To understand the geological speed of the Cambrian explosion, imagine the history of life compressed into a single day. If we imagine the history of life taking place in one 24-hour period, the current and scientific standard estimates for the origin of life placed the occurrence about 3.8 million years ago. If we start the clock at the top of a 24-hour period, six hours pass nothing but the single celled simple organisms appear, the same sort we saw in the beginning. 12 hours, same thing; 18 hours, same thing; three quarters of the day has passed and all we have are the simple single celled organisms. Then about the 21st hour in the space of about 2 minutes; Boom! Most of the major animal forms appear in the form that they currently have in the present. Many of these animal forms persist to the present, and we have them with us today. Less than 2 minutes out of a 24-hour period; that's just how sudden the Cambrian explosion was.
Darwin was caught in the grip of a deep dilemma. The fossil record showed him one thing; his theory told him something else. Darwin comes to an impasse at this point, and he says, "If this pattern holds, it is a genuine argument against my view." I believe 150 years later, we have added a great volume of detail to the explanation but I think the basic problem is still unsolved.
Absence of Transitional Fossils
Evolution works very slowly as Darwin saw it, with lots of failed experiments along way, and one would expect that over millions of years, as sediment is being deposited, that you would capture some of those experiments; some of those linking groups leading to the trilobites that Darwin knew all about. So the absence of such forms is profoundly mysterious. However, from the standpoint of intelligent design this is not mysterious at all because we know that intelligent agents can bring things into existence that did not exist before because they had an idea. They had a blueprint in their mind that they realized in their creative activity. There's no need to tinker through millions of years of evolutionary history if you can pull together a plan at a discrete moment in time. This is exactly what appears to have occurred in the Cambrian explosion.
Darwin said, "If numerous species belonging to the same genera, or families, have really started to life all at once, the fact would be fatal to the theory of descent with slow modification through natural selection."
Charles Marshall - Curator/Professor, Integrative Biology (UC Berkeley)
Paul Kwan Chien – Marine Biologist, known for his research on the physiology and ecology of intertidal organisms and his support for intelligent design and creationism.
Paul Chien, Senior Fellow – CSC – Discovery Institute
The Discovery Institute
Jonathan Wells – Author of Icons of Evolution - PhD Molecular and Cell Biology
Senior Fellow, Center for Science & Culture. Dr. Wells is an expert on biology textbooks and biology science curriculum as it relates to Darwinian evolution.
Icons of Evolution: Science or Myth? Why Much of What We Teach About Evolution Is Wrong
Irreducible Complexity (IC) and Specified Complexity -
Signature in the Cell: DNA and the Evidence for Intelligent Design, by Stephen C. Meyer
James Valentine – Author, On the Origin of Phyla
James W. Valentine is an American evolutionary biologist and Professor Emeritus in the Department of Integrative Biology at the University of California, Berkeley. He has published widely and -- in addition to peer-reviewed publications -- has written several books.
Paul Nelson, Philosopher of Biology at Biola University - Ph.D. Philosophy, University of Chicago
Darwin’s Dilemma Media Presentation, Illustra Media - The Intelligent Design Collection
Simon Conway Morris
The Burgess Shale
An Interview with Simon Conway Morris by Darwin Correspondence Project
The end of materialism - Simon Conway Morris
The Intelligent Design Collection on EQUIP.org