The Cambrian ‘Explosion’ Was Gradual

According to Wikipedia’s article on the so-called Cambrian explosion:

The Cambrian explosion or Cambrian radiation was an event approximately 541 million years ago in the Cambrian period when most major animal phyla appeared in the fossil record. It lasted for about 20–25 million years. It resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification of other organisms.

But according to the Discoveroids, the Cambrian explosion was a magic moment when their intelligent designer — blessed be he! — came to Earth and whomped up a whole bunch of new species. So who’s right?

To help you make up your mind, some new research is reported at PhysOrg. Their headline is Major fossil study sheds new light on emergence of early animal life 540 million years ago. Here are some excerpts, with bold font added by us for emphasis:

All the major groups of animals appear in the fossil record for the first time around 540-500 million years ago — an event known as the Cambrian Explosion — but new research from the University of Oxford in collaboration with the University of Lausanne suggests that for most animals this ‘explosion’ was in fact a more gradual process.

Egad — a gradual process? Then PhysOrg says:

The Cambrian Explosion produced the largest and most diverse grouping of animals the Earth has ever seen: the euarthropods. Euarthropoda contains the insects, crustaceans, spiders, trilobites, and a huge diversity of other animal forms alive and extinct. They comprise over 80 percent of all animal species on the planet and are key components of all of Earth’s ecosystems, making them the most important group since the dawn of animals over 500 million years ago.

A team based at Oxford University Museum of Natural History and the University of Lausanne carried out the most comprehensive analysis ever made of early fossil euarthropods from every different possible type of fossil preservation. In an article published today in the Proceedings of the National Academy of Sciences they show that, taken together, the total fossil record shows a gradual radiation of euarthropods during the early Cambrian, 540-500 million years ago.

Here’s the paper they’re talking about: Early fossil record of Euarthropoda and the Cambrian Explosion. Without a subscription, you can only see the abstract. PhysOrg tells us:

The new analysis presents a challenge to the two major competing hypotheses about early animal evolution. The first of these suggests a slow, gradual evolution of euarthropods starting 650-600 million years ago, which had been consistent with earlier molecular dating estimates of their origin. The other hypothesis claims the nearly instantaneous appearance of euarthropods 540 million years ago because of highly elevated rates of evolution.

The new research suggests a middle-ground between these two hypotheses, with the origin of euarthropods no earlier than 550 million years ago, corresponding with more recent molecular dating estimates, and with the subsequent diversification taking place over the next 40 million years.

Forty million years? We’d expect better from the intelligent designer. To make it even worse for the Discoveroids, they quote Professor Allison Daley, the lead author of the paper:

This indicates that the Cambrian Explosion, rather than being a sudden event, unfolded gradually over the ~40 million years of the lower to middle Cambrian.”

One last excerpt from PhysOrg:

Harriet Drage, a Ph.D. student at Oxford University Department of Zoology and one of the paper’s co-authors, says: “When it comes to understanding the early history of life the best source of evidence that we have is the fossil record, which is compelling and very complete around the early to middle Cambrian. It speaks volumes about the origin of euarthropods during an interval of time when fossil preservation was the best it has ever been.”

One question remains: How will the Discoveroids react to this? They can’t ignore it. It’ll be fun to see their reaction.

Copyright © 2018. The Sensuous Curmudgeon. All rights reserved.

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10 responses to “The Cambrian ‘Explosion’ Was Gradual

  1. 1 This is about the Euarthropoda. Is there anything about the big branch which includes us, the Chordata?
    2 I suggest that one not use the singular masculine pronoun “he” in referring to the agency of design. Contemporary English favors “they” when the gender is not significant. And in this case, even the number is not known (>=0), although a case can be made for the plural.

  2. Meyer has a real issue with that too.

  3. Michael Fugate

    but in YEC years, 40 million is only about 50, then again given that Jesus was supposed to be back in 30 years and it is now 2000, who knows?

  4. “Explosion” is a misnomer (like ”Big Bang”) and we know just how obtuse and literal-minded creationists are. Prothero, and others, have suggested “Slow-fuse”, which is probably more apt for the Cambrian.

  5. Dave Luckett

    Ah, yes, Michael Fugate: As 2 Peter 3:8 explains: “In the Lord’s sight one day is like a thousand years, and a thousand years like one day.”

    The latter would imply a ratio of 365000 to one for God’s time. So even God would experience the 40 million years of the Cambrian “explosion” as over a hundred thousand years. And that gets us from tube worms to trilobites and sea scorpions. There’s an awfully long way yet to go before we get to, oh, eusocial insects, or wildebeest or Canada geese.

    So I think a higher ratio than that is required. Or else we have to acknowledge the first half of the text as well – and admit that God simply doesn’t experience time at all.

    The day Thou gavest, Lord, is ended.
    One more tomorrow, most probably.
    But just why you did this, and what you intended,
    I have to confess is a problem for me.

    I really don’t know why you went to the trouble
    Of separating infinity
    To make time and space. Light and dark would seem double
    The effort. Why do it? What is it to Thee?

    It must be important – sun setting, sun rising,
    This morning, this evening, this sky, this sea.
    Time’s nothing to you. Why are you emphasizing
    How vitally urgent it must be to me?

    You think that I won’t hear his wheels close behind me
    Unless reminded by night and noon?
    All it takes is my knees – they’re enough to remind me
    I’m bound to get run over. Probably soon.

    You know that. Is that why you are the renewer
    Of morning, of evening, of night and day?
    We say, “One more day,” but we mean “One day fewer.”
    You say, “One day more”, and you mean what you say.

  6. Sorry to quibble, but by my arithmetic, ‘with a ratio of 365000 to one for God’s time, God would experience the 40 million years of the Cambrian “explosion” as a bit over 100 years.

  7. For the One Who Resides Beyond SpaceTime 40 million years means nothing. So of course it’s an explosion.

  8. skmarshall

    Hey Dave Luckett, nice work. (I’ve been hearing those wheels for a while now,)

  9. docbill1351

    Even more exciting will be the results from a new Cambrian shale discovery on the “other” side of the valley from the Walcott Quarry. I made the 12-hour, 2700 foot elevation gain (round trip) hike to the Burgess Shale in 2006. Walcott hypothesized that the shale would be about where he found it from exploring Mt. Stephen (a more arduous hike, if that’s possible) on the Field, BC side of the valley, where he found masses of trilobites. Last year or so it was announced that a rich Cambrian shale deposit, possibly more extensive than the Walcott Quarry, had been discovered around Mt. Stephen. The location is being guarded but, apparently, it’s “difficult” to get to. Having hiked to the Walcott which is considered “hard to strenuous” I have a great respect for “difficult!”

  10. FrankB. Ask a theist what they mean by “…Resides Beyond SpaceTime…”, and I guarantee you won’t get a coherent answer.