More Evidence Cambrian Explosion was Un-Darwinian

Posted on January 18, 2012 in Biology, Darwin and Evolution, Dating Methods, Fossils, Marine Biology, Origins, Physical Science

The Cambrian Explosion (the abrupt appearance of animal phyla in the earliest fossil layers bearing multicellular body plans) remains unmuffled.  Known by Darwin as a problem for his theory, it has become more problematic to his followers over time.  There are now many more Cambrian fossils than Darwin knew of, and they continue the pattern: sudden appearance of complex animals, complete with legs, digestive systems, eyes, and nervous systems.  Discoveries of Precambrian fossils have not helped: the ones that are more than microbial appear to be mere colonies of cells with no relationship to animals.  Here are more discoveries that fit this pattern.

Burgess shale tulip animals:  A new species of filter-feeding marine animal that resembles a tulip has been found on Mt. Stephen in British Columbia, Canada, site of the internationally famous Burgess Shale fossil bed.  Pictures of the fossils and an artist reconstruction can be found on PhysOrg.  Named Siphusauctum gregarium, the animal is about 8” high and lived in colonies.  The Burgess Shale is dated Middle Cambrian, but the existence of this fully-formed animal, complete with gut, foot anchor and pump to drive water through its “unusual filter-feeding system” implies a very short fuse between the Precambrian and its abrupt appearance.

Crustaceans with modern aspect:  Like lobster?  Think of the complexity of this animal with eyes, antennae, claws, legs, mouth parts equipped with mandibles, and internal organ systems, including a digestive tract and sexual organs.  Crustaceans are a highly diverse group of arthropods that include lobsters, crayfish, and crabs.  Among the crustacean subphylum are the branchiopods (which includes the fairy shrimp and water flea), ostracods (small shelled crustaceans; see diagram of complex internal organs on the Lake Biwa Museum site), and copepods (“oar-foot” swimmers; see Smithsonian for description).

At another site in western Canada called the Deadwood Formation, a trio of scientists from Cambridge, Hawaii and Canada found exquisitely-preserved crustaceans “of surprisingly modern aspect” in mudstone, a type of rock that was thought to form very slowly (12/14/2007).  The abstract of their paper in PNAS says it best:1

The early history of crustaceans is obscured by strong biases in fossil preservation, but a previously overlooked taphonomic mode yields important complementary insights. Here we describe diverse crustacean appendages of Middle and Late Cambrian age from shallow marine mudstones of the Deadwood Formation in western Canada.  The fossils occur as flattened and fragmentary carbonaceous cuticles but provide a suite of phylogenetic and ecological data by virtue of their detailed preservation. In addition to an unprecedented range of complex, largely articulated filtering limbs, we identify at least four distinct types of mandible. Together, these fossils provide the earliest evidence for crown-group branchiopods and total-group copepods and ostracods, extending the respective ranges of these clades back from the Devonian, Pennsylvanian, and Ordovician. Detailed similarities with living forms demonstrate the early origins and subsequent conservation of various complex food-handling adaptations, including a directional mandibular asymmetry that has persisted through half a billion years of evolution. At the same time, the Deadwood fossils indicate profound secular changes in crustacean ecology in terms of body size and environmental distribution.  The earliest radiation of crustaceans is largely cryptic in the fossil record, but “small carbonaceous fossils” reveal organisms of surprisingly modern aspect operating in an unfamiliar biosphere.

Other crustaceans had been found in the Cambrian, the authors say (see 7/20/2001, 10/4/2007), but “until recently, have been represented almost exclusively by “Orsten-type” taxa of minute body size (< 2 mm) and limited appendage differentiation.”  Even the Burgess Shale arthropods lacked the “key diagnostic characters among the inner leg branches and mouthparts,” they said.  The only previous fossil with convincing a crustacean mandible was dated Late Cambrian.

Previous “cryptic” fossils hinted at the presence of crustaceans in the Early Cambrian, but now, the new discovery shows them alive and well in the Middle Cambrian:  “the Deadwood fossils provide crucial phylogenetic and ecologic datapoints for charting a major Cambrian radiation of crustaceans.”  The Deadwood Formation extends from western Canada to the Black Hills of South Dakota.

After showing an array of beautifully detailed fossils and discussing them, the authors concluded that their discovery pushes back the date of branchiopods 80–100 million years (Lower Devonian to Middle Cambrian), ostracods 70 million, and copepods 190–210 million years.  They did their best to maintain their evolutionary belief, pointing to differences between the fossil forms and modern or later fossil forms, for example, “In any case, they offer clear potential for reconciling the Orsten forms with adults and larger bodied relatives for a new, high-definition narrative of early mandibulate evolution.”  Nevertheless, these fossils show “direct evidence for sophisticated particle-handling” and represent “the acme of Cambrian differentiation within appendages,” they said.

It’s hard to see evolution in the picture of “early origination and subsequent conservation in crustacean form and function” these fossils illustrate, especially when the fossil copepods are larger than modern ones.  To reconcile that with evolution, they postulated that the presence of fish with predatory eyes would drive crustacean size down.  Maybe they forgot that the Chinese found fish fossils in the early Cambrian (8/21/2002, 1/30/2003), but that seems the least of their worries.  The complex body parts represented in these fossils begs for explanation how a gradual, unguided Darwinian process would lead to such high levels of functional complexity in short order, abruptly, with no fossil pathway evident, much earlier than expected.

Up periscope!  Sea spider eyes:  Did you know there are spiders at the bottom of the sea?  A paper in PLoS ONE talked about them.2  They are called pycnogonids, and they have unusual eyes on stalks that look like periscopes.  The authors of the paper did not find Cambrian fossils of sea spiders.  Instead, they tried to infer their evolutionary origins, and placed them in the Cambrian as the oldest arthropods.  “Recently it was suggested that arthropod eyes originated from simple ocelli similar to larval eyes,” they said.  “Hence, pycnogonid eyes would be one of the early offshoots among the wealth of more sophisticated arthropod eyes.”

Putting puzzle pieces together in some kind of evolutionary arrangement, though, seems the least of their worries.  They found that these eyes had nerves from the stalks down to the brains of these eight-legged creatures.  How eyes popped into existence suddenly in the earliest layers bearing animal fossils is the “elephant in the room” that most evolutionists dodge.  They ended with an “if-then” statement of doubtful premise: “If arthropod eyes originated from simple ocelli similar to larval eyes, pycnogonid eyes could be one of their early offshoots, which date back at least 500 Myr to the Cambrian, and be older than the appearance of distinct lateral and median eyes.”  Notice that they are not saying sea spiders have “simple” ocelli (light-sensitive organs, as in dragonflies; see 8/13/2004), just that they were a later offshoot of a presumed ancestor, “if” arthropod eyes “originated” by evolution.

1.  Harvey, Vélez and Butterfield, “Exceptionally preserved crustaceans from western Canada reveal a cryptic Cambrian radiation,” PNAS, Published online January 17, 2012, doi: 10.1073/pnas.1115244109.

2.  Lehmann T , Heß M , Melzer RR , 2012 Wiring a Periscope – Ocelli, Retinula Axons, Visual Neuropils and the Ancestrality of Sea Spiders. PLoS ONE 7(1): e30474. doi:10.1371/journal.pone.0030474.

The Cambrian Explosion is not a problem for special creation; it is a problem for evolution.  Why do evolutionists get over 150 years of leadership in science for clinging to a belief that has been falsified by the evidence?  This is like giving astrologers hegemony in a day of modern astronomy.  Charlie’s little Victorian myth needs to go to the dumpster with phrenology, mesmerism and table-turning.  We need to look at the fossil record anew, without the black-tinted glasses of evolutionary assumptions.  That will “shed light on evolution,” all right; it will take the dark glasses off so that the pre-existing light that was ignored can reveal it for what it is, a chosen world view that demands all evidence be interpreted within its dark world of imaginary light.

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