Cambrian Explosion Solved

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Posted on October 31, 2010 in Darwin and Evolution, Fossils, Marine Biology

Geologists have come out swinging against the idea the Cambrian Explosion damages Darwinism.  In a lengthy new paper in the Geological Society of America Bulletin,1 they believe they pitch three strikes against creationists and intelligent-design supporters who claim that the sudden appearance of all the animal body plans at the base of the Cambrian falsifies Darwinian claims about gradual evolution.  Their last paragraph sums up their victory announcement that Darwin was right after all:

In his chapter on the imperfection of the geological record, Darwin alludes in passing to a different explanation for the supposed sudden appearance of animals in the lowest fossiliferous strata.  He writes “[w]e should not forget that only a small portion of the world is known with accuracy” (Darwin, 1859, p. 307).  It is this explanation—the incompleteness of our knowledge—that has turned out to be closer to the truth.  The problem of missing fossil ancestors was solved by the discovery of the Precambrian fossil record, the problem that nearly all the animal phyla appear in the Lower Cambrian with no evidence of intermediate taxa was solved by the recognition that most Lower Cambrian fossils represent stem-groups of living phyla, and the problem of the explosive diversification of animals at the start of the Tommotian was solved by improved correlation and radiometric dating of Lower Cambrian sequences—to which we contribute here—showing that this diversification was drawn out over more than 20 m.y.

This paper, with over 500 references, is probably the most extensive defense of Darwin against the Cambrian explosion since Charles Marshall explained in 2006 that, essentially, evolution did the evolution (see 04/23/2006).  These scientists from Princeton, MIT, UC Santa Barbara, and Washington University at St. Louis knew about Marshall’s paper, because they referred to it several times.  They also understood “Darwin’s dilemma” (not the film by that name, but the issue), saying, “The dilemma Darwin faced was that if all life descended via gradual modification from a single common ancestor, then the complexity and diversity of fossils found in Cambrian strata … demand a long interval of evolution prior to the beginning of the Cambrian.”  This was their challenge, and victory was their goal.
    They used a two-pronged approach of radiometric dating with comparisons of calcium carbonate isotopes in fossil shells to determine “a new absolute time line for first appearances of skeletal animals and for changes in the carbon, strontium, and redox chemistry of the ocean during the Nemakit-Daldynian and Tommotian ages at the beginning of the Cambrian.”  (The Nemakit-Daldynian strata are the first Cambrian after the Ediacaran era, dated from 542-525 million years before the present; the Tommotian follows, where the first trilobites appear).  As a result of their analysis of leading Cambrian outcrops from around the world (primarily Siberia), they claim that both the problem of disparity (morphological distinctness without intermediates) and rapid diversification “have been somewhat exaggerated.”  But can they undo 150 years of hand-wringing so easily?
    The argument for Darwin in this long paper can be summed up in two words: stretch and simplify.  By stretching out the timeline from 5 or 10 to 20 million years, they muffle the explosion.  And by claiming that the first appearances of the phyla were fairly simple stem-group members compared to those that came later, they leave less innovation for Darwinism to have to produce all at once.  The bulk of their paper concerns measurements of calcium carbonate isotopes, by which they argued that changes in ocean chemistry may have been responsible for the so-called explosion: aragonite was favored in the Nemakit-Daldynian, while calcite was favored in the Tommotian.  This pattern “supports the hypothesis that carbonate skeletal mineralogy is determined by the chemistry of seawater at the time carbonate skeletons first evolve in a clade.”
    Their revised timeline was a big part of their argument.  They mapped calcium carbonate isotope traces from Siberia, China and Mongolia onto uranium-lead dates from Morocco, a method that they claimed “avoids the circularity associated with using biostratigraphic correlations and that is presented in the context of coincident changes in the cycling of carbon and trace elements in the ocean.”  So, “Better than ever before, we are now capable of determining the absolute timing of biological and environmental change in the earliest Cambrian.”  Having a new radiometrically-determined timeline, they produced a key figure in the paper: a timeline of first appearances.  At 544 mya, they show anabaritids.  At 540 mya, they show protoconodonts, cap-shaped fossils, hyoliths, hyolithelminths, and caeloscleritophorans.  At 534 mya, they show molluscs, conulariids, cambroclaves, and paracaranichitids.  Coleolids and possible archaeocyaths show up at 532 mya, calcareous brachiopods at 528 mya, phosphatic bracheopods at 526 mya.  At 525 mya, the sea chemistry changes from favoring aragonite to calcite.  Shortly after, at about 523 mya, trilobites appear.  Put together, the pattern of diversification looks more like what Darwin envisioned – a gradual unfolding of new forms spread over 20 million years.
    The researchers also looked closely at patterns of diversity in the small shelly creatures that appear first in the lowest Cambrian layers.  They claim that four major groups in these shelly creatures, including molluscs, were all related, and therefore illustrate a “gradual unfolding of diversity through the Nemakit-Daldynian … rather than a burst at or just before the Tommotian boundary.”  In addition, they identified four possible bursts of diversity within the explosion.  Other sections on phosphate, strontium, and other ocean-chemistry data were used to envision scenarios of environmental changes that contributed to the rapid diversification of organisms in the Cambrian.  Looking at the big picture, though, they argued that the Cambrian explosion was really not all that special; other parts of the fossil record show similar patterns: “the observation that disparity reaches its peak early in a group’s history seems to reflect a general phenomenon, also observed in plants (Boyce, 2005), the Ediacara biota (Shen et al., 2008), Precambrian microfossils (Huntley et al., 2006), and within many individual animal clades, such as crinoids (Foote, 1997), gastropods (Wagner, 1995), and ungulates (Jernvall et al., 1996).  Although of significant interest, this high disparity soon after a group’s appearance is not unique to the Cambrian,” they said.
    So is the Cambrian explosion explained?  They didn’t claim such a landslide victory.  Instead, they ended (before the final paragraph quoted above), “An explanation for the processes responsible for the radiation of animals, and of whether the radiation was a consequence or a cause of associated geochemical changes, requires a thorough understanding of the pattern of that radiation, to which this paper contributes.”  The research was partly funded by the National Science Foundation.


1.  Maloof, Porter, Bowring et al, “The earliest Cambrian record of animals and ocean geochemical change,” Geological Society of America Bulletin, v.122 no. 11-12 p. 1731-1774 (November 2010), doi: 10.1130/B30346.1.

OK, guys, nice try, but no cigar; valiant effort, but no valium.  This “explanation” (or “contribution” toward an explanation) assumes much and explains little.  Fully half the bulk of this paper is taken up with 500 references from Darwin-Party sources and tedious nitty grit about isotopes of strontium, calcium carbonate and other distractions.  The elephant standing in the room is standing on Darwin.  The poor man needs help!  Don’t pore through your chemistry notebooks while he can’t breathe.
    Does his mechanism of mindless, undirected processes create body plans and genetic codes and complex organs or not?  Saying that miracles happen better if they happen slowly is not an answer!  Look at a trilobite.  It has compound eyes of sophisticated design and optical quality (09/13/2003), a gut, antennae, jointed appendages, and a central nervous system to operate them.  Do eyes just pop into existence?  Who made that happen – Popeye?  The first trilobites are not becoming trilobites; they are trilobites.  Same is true for all the phyla.  They are not microbes becoming cnidarians, or Ediacarans becoming worms; they are what they are when they appear in the record.  Their genetic programs know how to develop into complex body plans out of a single-celled zygote.  Moreover, the trilobite record is opposite evolutionary expectations – there’s more diversity in the lower layers (07/28/2007).
    Another huge, glaring omission in this paper is evidence for intermediate forms, the transitional forms that must have existed between all the phyla.  To talk over and over about the “appearance” of this complex animal, and the “appearance” of that complex animal is only multiplying miracles.  Where are the gradual transitional chains from simple to complex that Charlie is crying out for?
    There was a big lie in the conclusion that their own previous words exposed.  They announced in triumph at the goal line, “The problem of missing fossil ancestors was solved by the discovery of the Precambrian fossil record.”  In the Introduction, however, here is what they admitted, without ever coming back to it and solving the problem:

Despite abundant evidence for a variety of life extending back to at least 3.5 Ga, Precambrian fossils mostly record the evolution of bacteria and microbial eukaryotes.  The earliest evidence for animals predates the Precambrian-Cambrian boundary by only ~100 m.y.  (Xiao et al., 1998; Yin et al., 2007; Love et al., 2009, Maloof et al., 2010b), and the few unquestioned examples of Precambrian Bilateria are <15> (Fedonkin and Waggoner, 1997; Martin et al., 2000; Jensen, 2003; Droser et al., 2005).  Significant increases in trace fossil diversity and complexity across the boundary and the absence of soft-bodied animals in upper Precambrian Burgess Shale�type biotas (Xiao et al., 2002) suggest that the general absence of bilaterian animal fossils from upper Precambrian rocks is not a preservational artifact.  Rather, it appears that animals originated and began to diversify relatively close to the base of the Cambrian.  Although early studies using a “molecular clock” suggested that the divergences between major animal groups long predated the Cambrian (Wray et al., 1996; Bromham et al., 1998), some of the more recent work has produced dates that are closer to (if still older than) those supported by the fossil record (Aris-Brosou and Yang, 2003; Peterson et al., 2004, 2008).  Furthermore, Konservat-Lagerst�tten such as the Chengjiang biota and the Burgess Shale record a breathtaking array of soft-bodied animals by the late Early and Middle Cambrian (Briggs et al., 1994; Hou et al., 2004), respectively, and, together with more conventional skeletal assemblages, suggest a great radiation of animal life during the Early Cambrian.

You can give these Darwin-worshippers the most generous rope, stretching out the minimum claims of 5 m.y. for the explosion to 20 m.y., and the noose still won’t let their feet come near the ground.  The Cambrian explosion is real.  Appeals to calcium carbonate, carbon dioxide, oxygen, moving continents – none of that has the capacity to code for a complex body plan, developmental programs, and hierarchical designs as explained thoroughly in the documentary film Darwin’s Dilemma.  Watch the film!  It covers so much more than just the timeline – the least of Darwin’s problems, though even 20 million years is the blink of an eye in their evolution-incestuous dating scheme.
    Once again, the evolutionary explanation makes no sense unless you already believe in evolution.  To a creationist, it is question-begging nonsense.  Evolution is the question!  You cannot assume what your critics will not grant.  Did you catch the bad breath in their statement about microbes, ungulates and all?  “Although of significant interest, this high disparity soon after a group’s appearance is not unique to the Cambrian,” they said.  Good grief.  So they expect creationists to be converted to Charlie worship on the argument that “since miracles happened throughout the fossil record, it’s not hard to accept another one in the Cambrian.”  This is science class, remember?
    This long, tedious paper is no improvement on Charles Marshall’s circular paper that says, in a nutty shell, “evolution did the evolution.”  He promised his readers a long trip and dumped them off at the starting line.  The new paper does the same.  It also offers more of the “if you build it, they will come” theory of evolution: somehow, by unknown processes, if you give the ocean calcite, trilobites will pop into existence.  This foolishness appears over and over for those willing to wade through the endless details about chemistry: evolution is assumed when that is the very issue at stake –

  • Precambrian fossils mostly record the evolution of bacteria and microbial eukaryotes….
  • … many of the basic features that distinguish the major groups of animals had evolved by this time…
  • Lowest Cambrian trace fossils offer a record of the evolution of macroscopic, primarily soft-bodied, animals.
  • an age model … that we use to elucidate the evolution of small shelly fossils…
  • carbonate skeletal mineralogy is determined by the chemistry of seawater at the time carbonate skeletons first evolve in a clade…
  • …how many small shelly fossil genera must have evolved by a certain time…
  • …the skeletal mineralogy of animals that evolved during the Early Cambrian.
  • animals that evolve carbonate biomineralization associated with the youngest pulse of first appearances
  • …calcareous plankton had not yet evolved in the Early Cambrian…

This is so old.  Why won’t the Darwinians listen?  Stop talking in an echo chamber.  Stop assuming evolution, and stop assuming that appeals to evolution are going to be taken seriously by your critics.  No amount of scholarly jargon can cover for circular reasoning.  The fossil record is a record of design, not evolution.  To borrow a quip from Ronald Reagan, it’s not that our opponents are ignorant; it’s that they know a lot of things that aren’t so.

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