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The fats of evolution - Authors’ reply to New Scientist review

Authors’ reply to New Scientist review of ‘The Driving Force: Food, Evolution and The Future’ published in New Scientist, 16 June, 1990

New Scientist Review by Caroline Pond and Dick Colby, 27 January 1990

The Driving Force: Food, Evolution and the Future
by Michael A Crawford and David E Marsh

We would like to reply to your review of our book The Driving Force: Food, Evolution and the Future (review: 27 January, 1990).

The book was written for the lay reader, and offers a new view of the evolutionary process, ranging well beyond the confines of the current neo-Darwinist paradigm.

The “driving force” is the environment – all the ‘impact’ energies and particularly food being the major link between environment and organism - which causes initial genetic diversity. Which itself is specifically non random: selection “favours” or “grades out” the results. Contrary to impressions given in your review, our thesis strongly supports Darwin‘s original theory which stated there were two major driving forces in evolution: natural selection and “conditions of existence”. Our only criticism of Darwin is that he over - emphasized “selection” at the expense of environmental, or “impact” energies. It was those who came after Darwin who chose to ignore what he had said about “conditions”.

Darwin suggested that there were so many different external forces acting on evolution, and that their interplay was so complex, that the results may be put down to “chance”. He stressed, however, that the term “chance” was used "more for convenience than for accuracy".

Today’s orthodoxy chains us to “random” mutations and, since Weismann, has remarkably little to say about alterations in genetic expression.

Our thesis suggests that environmental impact energies and chemistry - including food (and such food not exclusively lipid) – causes change in genetic behaviour and later, mutation. This concept provides a simple chemical explanation as to how horses’ toes eventually turned into hooves, for example.

While certain scientific passages are difficult for some uninitiated readers, your reviewers should not have needed us to point out to them that, in a chapter debating hooves and claws, it is the secondates, not the primates, that are being discussed. Secondate herbivores face severe limitations of neural or brain lipids, caused by the destruction of many essential fatty acids in the digestive process. The physiology of primates is, by contrast, elegantly designed to capture the neural nutrients during placental and early development.

Your reviewers failed to mention the essential difference between our thesis and Hardy’s (50 year old) aquatic theory. Contemporary biochemical analyses of neural lipids point to the birthplace of the main line of developing hominid as being not the forest, but riverine, lacustrine, estuarine and the land-sea interface, a niche containing incredibly rich resources of the long-chain fatty acids, specifically used in the brain and nervous system. Migration inland, up rivers on to the savannah, would eventually cut off such landlocked dwellers from the finest sources of these nutrients.

To some, your review appeared over-emotional: yet despite its wordiness it lacked any real objective appraisal of the central thesis - that the environment and chemistry, through prohibiting, limiting or encouraging development in one direction or another, collectively represent a major directive force in evolution which has remained largely unexplored. In these days of considerable environmental and nutritional concern, we feel such topics should be re-examined in the context of evolution theory - as they are currently being re-examined in the context of medicine.

To attempt to cast our thesis aside with a review composed at random (there have been 40+ excellent ones) echoes Darwin‘s definition of “chance”: a review written more for convenience than for accuracy.

David Marsh
Michael Crawford

April 1990