It is fashionable nowadays to blame Anglo-Saxon culture and ideology for the recent mishaps of imperialism and capitalism. A few of us in the science and engineering community are happy to contribute to this fashion with a critique of a very particular Anglo-Saxon idea. We have within our sights perhaps the most cherished idea of the Victorian era, Darwin's theory of natural selection. While we have been musing in the stuffy coffee rooms of our technical faculties over the lack of any real scientific evidence for this theory of evolution, many secularist-humanist scientists, and of course Richard Dawkins in particular, have been championing Darwin as the bulwark of the European scientific enlightenment. Dawkins' commitment to science is understandable in the historical context of the European Christian churches' antagonism with scientific progress and, in the past decades, the US evangelical churches' disavowal of evolution in favour of creationist myths. However, Dawkins suggests that natural selection is an accepted scientific law and the primary biological process by which evolution takes place. This is not the case, as I hope to explain below.
Jean-Baptiste Lamarck's theory of the inheritance of acquired characteristics was superseded by Charles Darwin's "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life" in 1859. Briefly, the difference between these two theories is as follows. Defining evolution narrowly as the adaptation of biological organisms across generations to a changing environment, Lamarckian evolution is the result of a direct chemical interaction between each and every organism and the environment, whereas Darwinian evolution applies selectively to organisms that happen to have inherited random mutations favourable to survival and reproduction. Let's say that a change in the environment occurs around time zero. Lamarck proposed that all organisms, in struggling to deal with the changed environment, contain responsive chemical processes within the biological organs that pass hereditary traits to offspring, which naturally predispose the offspring to be more adapted to the changed environment. In this case, evolution takes place from one generation to the next at the same time (time zero) that the change in environment is taking place. However, in Darwin's view, it is random mutations that affect the adaptability of organisms in future generations. Hence, a random mutation in a singular organism, which takes place during reproduction many generations prior to time zero, leads in successive generations to a select group of organisms within the wider population carrying this mutation. When the change of environment takes place, it so happens that these mutated organisms are more capable of survival and reproduction than the rest of the population (including segments of the population with other mutations that are not favourable in the changed environment).
I'd like to put forward two criticisms of Darwin's theory. The idea of randomness in nature has been superseded by chaos theory. This theory states that in dynamic natural systems the outcome of any process, although appearing to be random and apparently bearing no connection with the starting conditions, is in fact the result of a very complex set of physical processes. In other words, the outcome of a particular natural process is extremely sensitive to the starting conditions, and widely different results are obtained with rather small changes in the starting conditions. In this case, any mutation during the reproduction of an organism is the result of chaos in nature, not randomness, and is highly dependent on the environment that the organism lives in at the time of reproduction. We may not be able to predict what mutations will take place, but we can say that mutations are intimately related to the environment. Furthermore, if we think of a chaotic biological process in terms of a complex set of chemical reactions, we can also speculate that the reactions would tend towards thermodynamic outcomes with respect to the environment. This tendency is adequately expressed by the Chatelier-Braun principle, which states that a reversible chemical reaction acts in the direction counter to any change in environmental conditions. Such thermodynamic principles are empirically verifiable and, if applicable to biological reproduction, would be consistent with a Lamarckian notion of evolution.
The second criticism relates to Richard Dawkins' extension of Darwin's theory. Dawkins is a proponent of gene determinism. Genes are said to be the unit of selection, whereby 'random' mutations in DNA during cell division or gamete (ovum or sperm) production lead to selected genes (those that survive and are readily reproduced in the changing environment). He further proposes that in effect genes are self-propagating physical entities ('selfish replicators' in his terms) and their influences extend far into the phenotype. This leads to the absurd view amongst advocates of Darwinian evolution that, essentially, women have not contributed to human evolution. Their argument is as follows. Since a woman produces all her lifetime's ova at one time, whereas a man produces sperm throughout the course of his life, mutations are much more likely in the case of the male gamete, and therefore men are primarily responsible for human evolution. The geneticist Steve Jones at UCL takes this line of thought to an end-of-evolution conclusion: 'human evolution is grinding to a halt because of a shortage of older fathers in the West' [The Times, 7 October 2008]. In fact, the scientific evidence is pointing to the womb as the primary location of biological adaptation, not through selection but a natural process of chemical responses to environment factors. The evidence is emerging from the relatively new field of epigenetics, particularly the work of Moshe Szyf and co-workers at McGill University in California. The headlines such as "Nurture Takes the Spotlight" [GeneImprint, 25 Apr 2006], "DNA is not Destiny" [Discover, 22 Nov 2006], and "Environment Becomes Heredity" [Miller-McCune, 14 Jul 2008] speak of a revolution (literally) in science, returning to a Lamarckian notion of evolution.
In conclusion, Darwinian natural selection is not only an unproven theory, but more and more a discredited theory. In addition, the latest research suggests that human biological evolution is not centred on our genetics, and certainly not on sperm-centred genetic mutations, but the wider systems biology of the womb.
Dr Mortaza Sahibzada is a research associate at Imperial College London. He can be contacted at m.sahibzada@imperial.ac.uk.
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