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ORIGINAL: alex123
One current proposal is that the apparently rapid divergence in the early Cambrian is caused by the evolution of the ability to generate hard body parts (tough proteins, calcite, carbonates, etc) that were much more easily fossilised.

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This would mean that the Cambrian does not reflect an explosion so much as the 'disclosure' of an existing diversification.

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<snip>There is quite a nice summary of the Cambrian at http://www.fossilmuseum.net/Paleobiology/CambrianExplosion.htm

Actually, this isn't true at all; there exists quite a bit of evidence that the Cambrian explosion occurred (indeed, that is the standard understanding in paleontology)

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as your own link acknowledges at the beginning:

Most major animal groups appear for the first time in the fossil record some 545 million years ago on the geological time scale in a relatively short period of time known as the Cambrian explosion.

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Indeed, there exists significant genetic evidence that the diversification of of major animal phyla in the genetic record as well.

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In addition, the Cambrian explosion wasn't the only 'explosion' of diversity in earth's past - the was the Avalon explosion, an explosion of major flowering plants, beetle types, etc.

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Rapid genetic diversification seems fairly certain - and the the arguments against it, for example that major genetic complexity is far older really don't contradict the occurence of such an explosion, in fact they make the gradual development of genetic complexity less likely.

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They certainly seem to appear at that time but there is considerable evidence (both palaeontological and genetic) that they were there earlier in a less visible form and therefore their appearance was not quite as sudden as it might appear.

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The 'Avalon' explosion was the emergence of the preCambrian Ediacaran fauna, not flowering plants, etc. ( http://www.sciencedaily.com/releases/2008/01/080103144451.htm)

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I agree with your first statement up to a point, but I don't think that the Cambrian represents the 'face value' explosion of form that has been claimed. There certainly seem to have been periods of rapid expansion in the fossil record but I don't think that the concept of a (geologically) instant explosion from 3 to 30+ metazoan body forms at the start of the Cambrian is borne out by the increasingly detailed examination of the evidence.
As for 'making the gradual development of genetic complexity less likely', I dont think that that follows at all.

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Actually, up to now most of the 'evidence' you have presented has either been speculative, or made the case worse by pushing genetic complexity back further in time, giving less time for such diverse forms to develop evolutionarily.

But in a way it doesn't matter; we know now the basic genetic information is very ancient, conserved, anticipatory, and did not develop by cumalitive additional means.

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It is an algorithm that lies at the humming heart of life, ferrying information from one set of symbols (the nucleic acids) to another (the proteins). An algorithm? How else to describe the intricacy of transcription, translation, and replication than by an appeal to an algorithm? For that matter, what else to call the quantity stored in the macromolecules than information?
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Using very simple counting arguments, Hubert Yockey has concluded that an ancient protein such as "cytochrome c" [see the latest posts in the Origin of species thread] could be expected to arise by chance only once in 10<44> trials. The image of an indefatigable but hopelessly muddled universe trying throughout all eternity to create a single biological molecule is very sobering. It is this image that, no doubt, accounted for Francis Crick's suggestion that life did not originate on earth at all, but was sent here from outer space, a wonderful example of an intellectual operation known generally as fog displacement.
- Berlinski - The End of Materialist Science Subject: Anti-Evolution Articles - Date: 12/2/1996