Evolution, Creation, and the Bible: Part 4
Another evidence listed in support of macroevolution is the revealed fossil record. In fact, much of evolutionary theory is derived from what are said to be transitional periods between various species. Campbell and Reece write:
The succession of fossil forms is compatible with what is known from other types of evidence about the major branches of descent in the tree of life…. Indeed, the oldest known fossils are prokaryotes [just as predicted by evolutionary biochemists]. Another example is the chronological appearance of the different classes of vertebrate animals in the fossil record. Fossil fishes predate all other vertebrates, with amphibians next, followed by reptiles, then mammals and birds. This sequence is consistent with the history of vertebrate descent as revealed by many other types of evidence.
The Darwinian view of life also predicts that evolutionary transitions should leave signs in the fossil record. Paleontologists have discovered fossils of many transitional forms that link even older fossils to modern species.[1]
As Campbell and Reece suggest (more explicitly elsewhere), the evolutionary tree of life is primarily a result of logic and the fossil record. Upon it, considerable theory rests.
Yet, screaming in the face of evolutionists is the Cambrian explosion. During this period – approximately 550 million years ago according to modern dating methods – “most of the major groups (phyla) of animals make their first fossil appearances during the relatively short span of the Cambrian period’s first 20 million years.”[2] Michael Behe explains further:
Careful searches show only a smattering of fossils of multicellular creatures in rocks older than about 600 million years. Yet in rocks just a little bit younger [roughly 565 million years old according to Campbell and Reece[3]] is seen a profusion of fossilized animals, with a host of widely differing body plans. Recently the estimated time over which the explosion took place has been revised from 50 million years to 10 million years—a blink of the eye in geological terms. The shorter time estimate has forced headline writers to grope for new superlatives, a favorite being the “biological Big Bang.”[4]
This explosion presents quite a significant challenge to Darwinian gradualism. According to Darwin’s theory of natural selection, time is a key factor. And, as Behe noted, 10 million years is not much time in geology. Even worse for evolutionists, admittedly “many of them [major invertebrate groups] already [exist] in an advanced state of evolution, the very first time they appear.”[5] How do evolutionists respond?
Richard Dawkins, the famed atheistic evangelist and evolutionary biologist, simply dismisses the explosion as gaps in the fossil record:
Evolutionists of all stripes believe…that this really does represent a very large gap in the fossil record, a gap that is simply due to the fact that, for some reason, very few fossils have lasted from periods before about 600 million years ago. One good reason might be that many of these animals had only soft parts to their bodies: no shells or bones to fossilize…. [T]he major gaps are real,…they are true imperfections in the fossil record.[6]
Campbell and Reece reply with a few hypotheses as to why the explosion occurred. In summary, they present three hypotheses. First, the emergence of predator-prey relationships caused animals to evolve protective devises, such as “shells and diverse modes of locomotion.” Second, oxygen likely “reached a high enough concentration during the Cambrian to support the more active metabolism required for the feeding and other activities of mobile animals.” Third, there may have been genetic mutations that affected embryonic development.[7] And finally, the famed and now late Harvard paleontologist Stephen Jay Gould responded to the Cambrian explosion in that he, along with Niles Eldredge, completely abandoned the traditional, gradualistic theory of Darwinism. Gould and Eldredge hypothesized what is now known as punctuated equilibrium, essentially stating that, sexual creatures do not evolve frequently, but when they do, they phenotypically evolve extremely rapidly.
But each of these responses is inherently weak in one sense or another. Dawkins’s dismissal of the Cambrian explosion as a “major gap” in the fossil record simply does not hold. He notes that many of the species were soft-bodied, implying that such boneless animals could not leave fossils. This is simply not true, though, as the fossil record is filled with soft-bodied animals even prior to the Cambrian explosion.[8] The hypotheses of Campbell and Reece in many ways seem rather naive. While the hypothesis that the increased presence of oxygen (what seems to be the strongest hypothesis) caused an evolutionary spark makes sense, it still does not explain the incredible diversity of the Cambrian. The other two hypotheses do not seem as strong. The predator-prey relationships of which they speak still do not provide reasoning for the diversity that is found (let alone a mechanism by which such new defense mechanism could arise!), and the third hypothesis seems very elementary in that it simply calls for genetic mutations found within the embryos. This is almost like saying, “Evolution is necessary for evolution to occur.” Finally, Stephen Jay Gould’s punctuated equilibrium theory has not been terribly well received among the evolutionary community, although his ideas do retain a significant following.[9] It seems that none can render a satisfactory explanation for what seems to be one of evolution’s biggest challenges.
[1] Campbell, Neil A., and Jane B. Reece. Biology. 6th ed. San Francisco: Pearson Education, 2002. 441.
[2] Ibid. 515.
[3] Ibid. 642.
[4] Behe, Michael J. Darwin’s Black Box: the Biochemical Challenge to Evolution. 2nd ed. New York: Free P, 2006. 27.
[5] Dawkins, Richard. The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design. 3rd ed. New York: W. W. Norton, 1996. 229.
[6] Ibid. 229-230.
[7] Campbell, Neil A., and Jane B. Reece. Biology. 6th ed. San Francisco: Pearson Education, 2002. 643.
[8] See, for instance, Gehling, J.G. and J.K. Rigby. “Long Expected Sponges from the Neoproterozoic Ediacara Fauna of South Australia.” Journal of Paleontology. Vol. 70. No. 2, 185-195.
[9] For a criticism of Gould, see Dawkins, Richard. The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design. 3rd ed. New York: W. W. Norton, 1996. 223-252.
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