Uncommon Descent reports on a new paper in the most prestigious peer-reviewed science journal.
A new paper has just been published in Nature by Gregory J. Retallack of the University of Oregon. The paper argues that the Ediacaran fauna are not ancestral to the animals which arose in the Cambrian explosion and that life existed on land 65 million years before previously thought. Retallack further argues that the iconic fossils of Dickinsonia and Springgina, which appear in the Precambrian Ediacaran assemblages, were not in fact animals at all. Rather they were, according to Retallack, lichens, soil structures and traces of slime moulds.
And they link to this post about the paper from Science Daily, which makes the significance of the discovery even clearer:
Ancient multicellular fossils long thought to be ancestors of early marine life are remnants of land-dwelling lichen or other microbial colonies, says University of Oregon scientist Gregory J. Retallack, who has been studying fossil soils of South Australia.
[...]“This discovery has implications for the tree of life, because it removes Ediacaran fossils from the ancestry of animals,” said Retallack, professor of geological sciences and co-director of paleontological collections at the UO’s Museum of Natural and Cultural History. His evidence, mostly gathered from a site in the Flinders Ranges, is presented in a paper placed online ahead of print by the journal Nature.
“These fossils have been a first-class scientific mystery,” he said. “They are the oldest large multicellular fossils. They lived immediately before the Cambrian evolutionary explosion that gave rise to familiar modern groups of animals.”
Retallack studied numerous Ediacaran fossils and determined that the diversity reflects a preference by the ancient organisms for “unfrozen, low salinity soils, rich in nutrients, like most terrestrial organisms.” Thus the fossils in Australia’s iconic red-rock ranges, he concludes, were landlubbers. In his closing paragraph, Retallack outlines implications for a variety of other Edicaran fossils, that could have been lichens, other microbial consortia, fungal fruiting bodies, slime molds, flanged pedestals of biological soil crusts, and even casts of needle ice.
Ediacaran fossils, he said, represent “an independent evolutionary radiation of life on land that preceded by at least 20 million years the Cambrian evolutionary explosion of animals in the sea.” Increased chemical weathering by large organisms on land may have been needed to fuel the demand of nutrient elements by Cambrian animals. Independent discoveries of Cambrian fossils comparable with Ediacaran ones is evidence, he said, that even in the Cambrian, more than 500 million years ago, life on land may have been larger and more complex than life in the sea.
Here’s a quick re-cap of the Cambrian explosion:
Part 1: (7:50)
Part 2: (3:25)
This explosion in biological complexity fits nicely with an intelligent designer . Intelligent agents make information by sequencing symbols into functional instructions. That’s what new body plans are. It’s like new software, and new software requires a software engineer.
The standard naturalist response to this problem of sudden origins of anaimal body plans used to be that the Cambrian explosion did have precursors. The precursors were thought to be the Ediacaran fossils. But that’s all been shot to Hell now, with this new paper in Nature. Ooops!