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Cambrian Explosion Excuses: Theme and Variations

Cambrian Explosion

When addressing the Cambrian explosion, evolutionists retreat to tried-and-true excuses. Darwin, we know, needed gradually changing transitions but the fossil record showed near-instantaneous new forms. Darwin’s dilemma remains to this day. Despite the contrary evidence, his defenders keep playing the Darwin March theme, with variations like: the oxygen theory, the niche theory, the predator theory, the hidden long fuse theory, and others reported on for years since Stephen Meyer wrote Darwin’s Doubt. Now, instead of a new theme, they are trying combinations of the old variations, hoping that listeners might enjoy polytonality or something slightly different.

The latest attempt comes from Rachel Wood and eight others. In Nature Ecology & Evolution, they try a medley of old variations. The paper is titled: “Integrated records of environmental change and evolution challenge the Cambrian Explosion.” They mean that the medley challenges the existence of an explosion. This new variation supposedly gives Darwin all the time he needed to gradually evolve trilobites.

This latest paper has a whopping 130 references. It gives the appearance that they consulted every expert on the subject. Yet the only thing new in this paper is the particular combination of excuses.

Excuses, Coming Up

An article for Live Science summarizes the “new” variation: a series of “radiations” of which the Cambrian Explosion was just one episode in a long rhythm of smaller explosions. The reporter titles her article, “Early Animal Life Exploded on Earth Even Earlier Than Once Thought.” 

Beginning about 541 million years ago, life on Earth exploded. Over a 53-million-year period, gigantic sea creatures, armored worms and bizarre-looking filter feeders filled the primordial seas. Nearly all the animal body plans that exist today first appeared in primitive form during that time.

Or so scientists thought. [Emphasis added.]

Meyer never thought that. And he certainly would not think that the new variation is impressive:

In fact, a new analysis suggests that the Cambrian explosion may not have been a true explosion at all, but rather a series of waves — and those waves began millions of years earlier than previously believed.

Now that we have the gist of the variation, let’s see how they develop it. They replace biology’s big bang with a series of bangs which, for all practical purposes, are sudden events inexplicable by Darwinian processes. Is a string of little bangs over a longer time any better than one big bang? Rachel Wood admits the obvious before defending the new theory:

There’s no doubt that in the Cambrian there was an explosion of bilaterian forms [bodies with two symmetrical sides] — that’s all the animals except the sponges, corals, jellyfish and so on,” Wood told Live Science.

OK, so? 

But recent fossil discoveries dating to the Ediacaran period (635 million to 542 million years ago) suggest that many new soft-bodied species first arose long before creatures with skeletons showed up during the Cambrian, Wood told Live Science.

Reaching back in time, they present a variation on the Ediacaran-as-ancestors theory.

For the study, the researchers conducted a sweeping evaluation of existing research in fields such as geochemistry, stratigraphy and paleontology, Wood said. They also analyzed fossil finds from both the Ediacaran and the Cambrian, creating the first integrated picture of what happened before, during and after the Cambrian explosion.

They discovered that some physical features found in Cambrian creatures were also present in organisms from older rocks. These collections of creatures form a transitional bridge “between what was thought to be typically Ediacaran and what is typically Cambrian,” Wood said.

What are the “physical features” in earlier rocks? Trace fossils! Burrows! Nothing concrete that you can look at. But Meyer and all the other Darwin skeptics knew about these things.

The Band Plays On

The Darwin band now plays all the variations together. Rachel Wood calls it “Holistic integration of fossil and geochemical records.” The program notes explain:

We focus here on integrating the tractable fossil and environmental proxy records of the Ediacaran–Cambrian interval to document the diversification of animals and their behaviour. This integration reveals a record of interactions between environmental change and biological evolution, culminating in the establishment of the crown-group metazoan phyla. Our compilation enables a re-evaluation of the record and explores the potential drivers of early metazoan evolution.

This “integrated” variation has all the geological themes, geochemical themes, and ecological themes playing on top of each other. The oxygen theme is in there. Fossils are in there. Molecular clocking and radiometric dating are in there, playing the rhythm section. Even extinctions are called on to play, as if “evolution by subtraction” can help. They seem to hope that the resulting cacophony gives more time for Darwinian gradualism. Lost in the din is the ID proponent’s calling out from the balcony, “By the way, what is the source of the biological information for new body plans?”

The paper’s Abstract promises a big new melodic line:

The evolutionary events documented during the Ediacaran–Cambrian interval coincide with geochemical evidence for the modernisation of Earth’s biogeochemical cycles. Holistic integration of fossil and geochemical records leads us to challenge the notion that the Ediacaran and Cambrian worlds were markedly distinct, and places biotic and environmental change within a longer-term narrative.

(Emphasis on “narrative.”) But alas, the big new melodic line quickly returns to older variations: the oxygen theory, the nutrient theory, the niche theory:

We propose that the evolution of metazoans may have been facilitated by a series of dynamic and global changes in redox conditions and nutrient supply, which, potentially together with biotic feedbacks, enabled turnover events that sustained multiple phases of radiation. We argue that early metazoan diversification should be recast as a series of successive, transitional radiations that extended from the late Ediacaran and continued through the early Palaeozoic. We conclude that while the Cambrian Explosion represents a radiation of crown-group bilaterians, it was simply one phase amongst several metazoan radiations, some older and some younger.

A Circular Notion

Basically, if evolution has opportunity, it will fill it with endless forms most beautiful. It’s circular: “Because evolution innovates things, it will innovate things if given the opportunity.” But that’s not the issue. What is the source of biological information for new body plans? Take all the time you want. Take all the oxygen and food you want. “Here, Ediacarans; would you like more carbon with your oxygen?” None of those factors are going to build a trilobite or a comb jelly! The notion is as silly as the old belief in spontaneous generation, where scientists of the day actually thought that laying out straw would cause mice to emerge. This time, it’s oxygen and “biogeochemical cycles.” Poof! Trilobites!

None of the variations, singly or in combination, drown out Meyer’s central argument, that hierarchical structures (body plans) provide positive evidence of intelligent design, based on causes now in operation (i.e., intelligence) that we know can do the job. Padding the big explosion with other smaller radiations over more time in a changing “biogeochemical environment” is not going to help. Padding the paper with 130 references won’t solve it, either. Without an answer to that question, nothing else matters.

Truman’s Law

If you cannot convince them, Truman’s Law says, confuse them:

Indeed, the relationship between oxygen availability and biotic response was likely to have been complicated by the operation of ecological and genetic factors, as well as poorly understood feedbacks between life and the broader Earth system….

Animals most likely originated in a non-uniformitarian world with a low level of atmospheric oxygen, almost certainly before the permanent oxygenation of the deep ocean. However, it remains unclear whether animal diversification and increased ecosystem complexity were driven extrinsically by the expansion of permissive oxic niche or by genetic or developmental innovations that enabled animals to expand into the oxic realm.

The new whole-band variation ends without resolving.

This geochemical instability may have driven pulses of evolutionary innovation, but biotic feedbacks are poorly understood. Ecological and evolutionary responses to this instability could have wide-reaching implications for discussions of gradualistic versus punctuated evolution.

A scan of the paper reveals frequent phrases like “poorly understood” or “remains unclear” or “unknown.” It’s like hearing a piece played on poorly-tuned instruments, ending without a cadence to the tonic pitch. Everything is a cacophony of possibilities and speculations, wondering if rises and falls of oxygen triggered “innovations” here and there. 

A skeptical look at their colorful charts, however, confirms the explosion. It shows abrupt appearances of “limbs; vision; through-gut” at the base of the Cambrian, with only some dubious indirect inferences from trace fossils and burrows lower down suggesting, without hard evidence, possible progenitors of the Cambrian animals. The paper contains zero references to the source of biological information. The authors admit to the appearance of innovations in the fossil record, but attribute them to evolution. That’s circular reasoning.

Look at a trilobite. Consider its compound eyes, antennae, articulated limbs, gut, brain and other integrated systems, all working together. It doesn’t resemble anything that came before. It just appears in the fossil record, with other complex animals. Turn down the volume on the broken record playing “Theme and Variations on the Darwin March” and in the quietness of your logical mind, think. What causes now in operation do we know can build hierarchical levels of complex, functional design like that? 

Photo: Not a “true explosion”? Scientists search the fossil record; by Rachel Wood via EurekAlert!