The Cambrian explosion refers to a period of time 530 million years ago when many animal phyla first appeared on earth. Darwinism predicts that these phyla should have evolved from simpler organisms. If that were true, fossils left by those organisms might provide evidence for their existence. However no such fossils have ever been found. One might suppose that the ancestors of the Cambrian phyla existed but the fossil record is incomplete because conditions at the time were not right for preservation of fossils, or erosion destroyed their fossils, or they did not have shells and their soft tissues did not leave fossils, or their fossils exist but have not yet been found. However, many fossils from before the Cambrian era have been found. In fact, enough precambrian fossils of soft-bodied organisms have been found for the missing ancestors of the Cambrian explosion to have been found if they existed. Therefore the fossil record shows that many animal phyla arose without evolving from simpler organisms. This contradicts the theory of evolution by natural selection but is predicted by intelligent design.
From Deepening Darwin's Dilemma by Jonathan Wells
So there is now no shortage of Precambrian fossils. Not only do we have fossils of bacteria, but we also have many fossils of soft-bodied Multicellular organisms. “In the Ediacaran organisms there is no evidence for any skeletal hard parts,” wrote Conway Morris in 1998. “Ediacaran fossils look as if they were effectively soft-bodied” (Crucible of Creation, 28).
That the precursors to the Cambrian groups are indeed missing from the record is widely accepted among paleontologists; thus, this is not the controversial aspect of the ID position. About the missing precursors at the base of the tree of the animal phyla, Valentine notes:Pre-cambrian fossils include:
...many of the branches, large as well as small, are cryptogenetic (cannot be traced into ancestors). Some of these gaps are surely caused by the incompleteness of the fossil record..., but that cannot be the sole explanation for the cryptogenetic nature of some families, manyCharles Marshall concurs:
invertebrate orders, all invertebrate classes, and all metazoan phyla.
While the fossil record of the well-skeletonized animal phyla is pretty good, we have virtually no fossils that are unambiguously assignable to the most basal stem groups [putative ancestors] of these phyla, those first branches that lie between the last common ancestor of all bilaterians and the last common ancestor of the living representatives of each of the phyla….their absence is striking. Where are they?To be clear: Valentine and Marshall, leading paleontologists, oppose ID theory.
Charia, which is a single celled algae, originally wrongly thought to be a shelly invertebrate due to more misguided attempts to solve ‘Darwin’s Dilemma.’
Barghoorn Gunflint microfossils, which again comprise bacterial stromatolites that do not serve as precursors to the Cambrian fauna.
Bitter Springs Chert, which again are microbe fossils, not clear evolutionary precursors to the Cambrian fauna.
Saucer-sized organisms, at Ediacara, also called the Ediacaran Fauna, which are enigmatic fossils generally not thought to be ancestral to the Cambrian fauna.