NeoDarwinism

The fourth theory of evolution, and the paradigm endorsed by a majority of life scientists, is Neo-Darwinism. The brainchild of Charles Darwin, it has become almost synonymous with the word evolution itself. The theory states that Life evolved gradually from perhaps a single form roughly 3.5 billion years ago, branching out over time to produce numerous diverse species through (mostly) the mechanism of natural selection.[i] Jerry Coyne writes that this summary contains six components: evolution, gradualism, speciation, common ancestry, natural selection (NS), and nonselective mechanisms of evolutionary change. The essential idea is that over time creatures undergo random changes in their genetic makeup (mutations), and those varieties or variations that reproduce the best over geologic time (those that are the “fittest”) are selected for, resulting in new species that are best adapted to, or suited for, the existing environment.

For example, how did the stick insect in Figure 0.2 come to be? Creationism and ID insist that God has created the organism whole cloth. Neo-Darwinism offers a naturalistic explanation:

Fig. 0.2. The stick insect Ctenomorpha chronus. Courtesy Fir0002 and Wikimedia Commons.[ii]

The creature descended gradually from ancestors via random mutations to its genome, with those variations of form that produced the present shape selected for their adaptability to a changing environment. Neo-Darwinists state that in effect the constant sieving action of NS, acting over geologic time, has enabled the genes underlying Ctenomorpha to become fixed in its population because it reproduced the most prolifically.

So what are the mutations, or variations in genomes, that led to such changes? Carroll[iii] points out that there are many different kinds of DNA mutations, including substitutions of single letters or blocks of letters, deletions, duplications of groups or blocks of letters, duplications of entire genes, rearrangements of blocks of letters, and the breakage and rejoining of segments of genes. He notes that in humans there are an estimated 175 new mutations among the 7 billion DNA letters in every individual. There are in all this variation abundant opportunities for the modification of existing forms. How should we view this potential for change? Are we at the mercy of random forces ranging from mutations to earthquakes and tsunamis? Or could it be that random change in genomes is an ability or strategy that Life employs to deal with challenges and changing circumstances?

Richard Colling,[iv] former chairman of the Department of Biology at Olivet Nazarene University, argues in his book Random Designer that random variation followed by NS is indeed the design strategy granted to Life[v] by the Creator to generate the diversities of living things that culminate in Homo sapiens, an organism capable of connecting with the Creator. He defines random design as “a powerful method for creating higher order, particularly in living beings. It functions by first generating large arrays of potential building blocks from which the most suitable candidates are sequentially incorporated into an ever-advancing architectural design[vi] [italics mine]. Note that while Coyne sees evolution as accidental and by chance, Colling sees random variation followed by NS to be God’s grand strategy in creation. Colling would be the first to agree that his model is not science but rather a religious interpretation of his best understandings of science; as such, it is, to my knowledge, the first reconcilement of Christianity and Neo-Darwinism.

It seems far-fetched to posit that exquisite and harmonious complexity can emerge from random processes. But if you think of Life deploying randomness as a strategy, you suddenly have a different and exciting paradigm. For example, “directed evolution” is a widely used biotechnology method that exploits Life’s strategic use of random genetic variation to evolve novelty. Bioengineers have resorted to directed evolution to improve “the stabilities or biochemical functions of proteins by repeated rounds of mutation and selection.”[vii] Experimenters begin with the protein they wish to improve upon, followed by isolation of the organism’s gene that has generated the protein. In the next step, mutants of the gene are produced by causing it to replicate using error-prone polymerases (enzymes that facilitate the building of new copies of genes, in this case with errors—that is, mutations). The resulting replicating genes have one or two random mutations, and they produce an array of protein gene products with varying configurations. These products are then screened (NS), and improved, useful and often novel and unexpected proteins are harvested, and the non workable proteins are rejected. A hypothetical application might be to take a bacteria with a taste for crude oil and bioengineer it to more rapidly eat and digest petroleum products floating in the water following an oil spill. “Thus directed evolution can be used to discover mutations that fine-tune circuits and pathways and optimize their performance, all without requiring a detailed understanding of the mechanisms by which those improvements are achieved.”[viii] Now, compare this account of directed evolution to Colling’s definition above of random design.

I want to emphasize the central importance of strategy. Just as directed evolution is
a strategy of human beings, so Neo-Darwinian evolution is, in Colling’s and our
religious framework, one of Life’s strategies to cope with environmental
changes and other challenges to its survival. But there are other paths to
evolutionary change: This brings us to the fifth school of evolutionary
thought, MetaDarwinism.

 



[i] Coyne JA. Why Evolution Is True (New York: Penguin Books Worldwide, 2009).

[ii] Image at http://commons.wikimedia.org/wiki/File:Ctenomorpha_chronus.jpg

[iii] Carroll SB. The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution (New York: WW Norton, 2006).

[iv] Colling RG. Random Designer: Created from Chaos to Connect with the Creator (Bourbonnais, IL: Browning Press, 2004).

[v] I reify “Life” because it is in essence a unitary whole. All Life is intimately interconnected and has in common a genetic and molecular makeup. All Life shares the Breath of Life provided by God. More on this later in the chapter.

[vi] Colling, Random Designer, p. 1.

[vii] Bloom JD and Arnold FH. “In the Light of Directed Evolution: Pathways of Adaptive Protein Evolution.” PNAS 106 (June 16, 2009):9995-10000.

[viii] Dougherty MJ and Arnold FH. “Directed Evolution: New Parts and Optimized Function,” Curr Opin Biotechnol 20, no. 4 (Aug. 2009):486–91.

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