Talk:Cambrian explosion
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Beginning Discussion
I added a very basic starting page on this topic, but I'd like to see it considerably expanded. This event is the source of numerous creationist claims and is highly controversial within the scientific community, so I believe it would be helpful to thoroughly explore the topic in EvoWiki to assist in refuting creationist claims based on their misinterpretation of the event. I intend to add some more to this page but it's somewhat outside my expertise so I'll just be reviewing the writings of others. If other EvoWikians have more direct knowledge that would be great to have this topic accurately and thoroughly presented.
It seems the "snowball" earth hypothesis (how sound is this?) offers two key elements to the 'explosion' story. First, life might have been quite difficult during the severe climate and so a dramatically improved climate could lead to more rapid speciation. Second, the melting of huge amounts of ice may have provided the fine sediments that allowed the highly unusual fossil beds to form.
How many Precambrian rocks are still around? Have many/most be recycled due to 500 million years of erosion making Precambrian fossils hard to find?
Does molecular evidence suggest that hypervariability mechanisms (rather than simple mutation) originated about this time and then proofreading mechanisms evolved to counteract the dangerous hypervariability in the genome?
--Dmill96 19:26, 10 April 2006 (BST)
I guess the first place to start would be at Wikipedia, they have some great articles about the Cambrian and Precambrian... http://en.wikipedia.org/wiki/Precambrian http://en.wikipedia.org/wiki/Cambrian As far as I know, almost all known animal phyla, aside from Bryozoa, have at least some fossil representatives from the Cambrian. And some important Precambrian rock outcroppings include Namibia and South Africa, the Edicara Hills in Australia, India, Russia, and China.--Mr A. 22:13, 10 April 2006 (BST)
Removed Response
"There are almost a dozen Ediacaran fossil sites with many multi-celled (or at least "large") soft-bodied creatures. Thus, claims that there are insufficient pre-cambrian fossil sites or that only hard-parts were preserved is incorrect. However, the Ediacaran forms bear very little resemblance to Cambrian biota, and thus do not show "evolution"."
I removed this from the main page because some of the Ediacarans do have relatives in the Cambrian, such as Charnia, and the Burgess Shales cnidarian/sea pen Thaumaptilon, and the way Parvancorina, Praecambridium, and Vendia resemble the meraspid larval form of trilobites, as well as the adult forms of some Cambrian arthropods like Skania.--Mr A. 20:54, 14 January 2007 (UTC)
