Denis Venema wants to explain evolution to evangelical Christians because he doesn’t think it is understand sufficiently. But he asks us to use our imagination and avoids a carefully modelled defence of evolution. If that is the best Darwinists can do then is it any wonder that many of us reject it? See:
Venema Understanding Evolution: An Introduction to Populations and Speciation
Firstly, Venema follows the common evolutionary practice of presenting evidence for evolution by focussing upon the micro changes and then extrapolating without evidence to the macro evolutionary scale by assuming it happens by similar means. But the micro changes, such as that of his exampled stickleback fish, are simply uncontested even by young earth creationists, but what is contested is the belief that we can move from the small to the big without developing and modelling a credible pathway. Time and again evolutionists fail to deal with the problems, but simply make the switch from small to big thinking the flaws in their reasoning will not be noticed.
Venema though asks us to use our imagination to understand evolution. I find that wholly inadequate scientifically, especially when we can model such claims mathematically. And I wonder why such imaginary thinking has a right to be called science. He does though present claims that can be questioned scientifically; for instance believing that humanity evolved within a population size of roughly 10,000 people. So how should we model these claims?
Assuming 20 years for a generation and 6 million years from an ape-like ancestor to mankind would give 300,000 generations to achieve an evolutionary progression from an ape-like ancestor to man. As an aside, in that time only 3 billion individuals would have lived and died, a smaller number than the present human population alive today. Does he really expect us to believe that man could have arisen in so small a number of ancestors? Presumably we can look at the incidence of beneficial mutations in the present human population and ask whether sufficient beneficial mutations would have arisen and be compounded through 300,000 generations. I am afraid it doesn’t look good for evolution.
So down to modelling; we are led to believe that there is 1 percent difference between ape and man in the 3 billion base pairs of DNA, and if we use unrealistic assumptions then we might assume only 10 percent of DNA is coded with the rest considered ‘junk.’ But even 1 percent of 300 million is 3 million nucleotide differences between ape and man.
So we have to find 3 million base-pair beneficial mutational changes in 300,000 generations, or 10 per generation, both found and fixed in the population per generation. Is that possible? I challenge anyone to tell me it is adequate from what we know about the way the present day human population finds and fixes beneficial mutations, even for instance on a small island community of 10,000 people. It comes up against a number of problems.
Problem1. Haldane’s dilemma as discussed by ReMines in The Biotic Message and Sandford in Genetic Entropy (Refs below) (One might have thought these books would be at the top of Venema’s reading list considering his position). Anyway, as a simple overview of the claims of these books, in order for beneficial mutations to be fixed in the population we would need to pay a cost in terms of survivability of the mutated offspring against the un-mutated ones. Haldane thought it as high as 30 to 1, and higher vertebrates cannot hope to pay that cost. Haldane thought a cost of 0.1 per generation might be affordable and that it would take 300 generations to fix 1 beneficial mutation in a population. Venema’s population might then fix 1000 beneficial mutations in 6 million years; a little short of the 3 million required.
Problem 2. We may also ask whether beneficial mutations actually provide any selective advantage to an organism. Sandford for instance has pointed out that beneficial mutations, when they rarely occur, are virtually invisible at the level of the phenotype anyway and so even Haldane’s 0.1 per generation looks unlikely.
Problem 3. Harmful mutations are far more common than beneficial ones, perhaps as high as 1000 to 1. In order to weed out the harmful mutations evolution would have to proceed at a very slow rate indeed so that error catastrophe doesn’t occur in the population; a problem known today where small inbreeding populations are often on the verge of extinction. Furthermore, small populations do not have sufficient resources to find the necessary beneficial mutations, even though it makes it easier to spread the mutations that do occur through a population. A large population is more likely to find beneficial mutations, but work against their spread through the population due to the size.
So in summary, I would challenge Venema to respond seriously to the questions raised by Sandford and ReMine.
Sources: Walter ReMine’s The Biotic Message, St Paul, Minnesota: St Paul’s Science, pp. 208-236. Sanford, J (2005) Genetic Entropy and the Mystery of the Genome, New York: Elim Publ, especially pp.159-160, Haldane JBS (1957) ‘The Cost of Natural Selection,’ J. Genetics 55:511-24.