Chapter Eleven: Mechanisms Of Human Evolution In The 21st Century

I. Introduction

There is plenty of controversy over the nature of evolution, in particular about whether a mechanism similar to Darwinian evolution might apply in spheres other than the biological. Politics, culture, society, music, economics and bee-keeping can all evolve, in a general sense of the word, but can they evolve in a Darwinian way? Since Darwinian evolution involves the death without issue of unsuccessful combatants in the struggle to survive it seems hardly possible that the concept could be usefully applied outside its original sphere. Most of the confusion is surely terminological. If the word evolution is taken to mean 'development', then it is fine to use it in all kinds of contexts, and that is how it will be used here. When Darwinian evolution is meant, the whole phrase will be used.

Some writers strugggle towards a general theory of 'evolution', as if Darwinian evolution might itself be no more than a special case of a grander theory. That endeavour seems unnecessarily pretentious: change is inherent in our universe, and the state of everything changes over time, sometimes for the better and sometimes not.

The confusion is made worse by the fact that the subject of Darwinian evolution about whom we care most, that is, Man, has changed as a result of non-Darwinian evolutionary pressures at the level of the social group. For a while, some anthropologists held that Darwinian evolution (anyway, selection) operated at the group level. 'Group selection', as it was called, had its heyday in the middle of the 20th century. It is now discredited, but at the time a group selectionnist would have it that competition between groups was a proxy for competition between individuals, and that the human genome could be affected by success or failure at the group level.

Competition at the group level can certainly sharpen the effect of Darwinian evolution: if successful social groups require conforming members, then individuals will become conforming (and did) in order to belong to successful groups. But the social group is no more than another feature of the outside world which conditions the success or failure of the individual. The group developed, and successful groups gave their members better life and mating chances; no more or less than that.

Group selection theory had a Lamarckian 1 tinge; and recent work has seemed to show that there are after all some Lamarckian features of genome development – there are situations in which the life experience of individuals can feed back to their DNA. But at the present state of knowledge, these are not sufficient to derail a predominantly Darwinian view of individual evolution.

These considerations are highly relevant to a discussion of the workings of human evolution in the 21st century, since there will be environmental, cultural and social change at a rate never before experienced – if Lamarckian evolution had more than a tiny foothold in the human development process, then this would come to have a major impact on the human genome, as will appear later. But for now, Lamarck may remain in the wings.


1Jean-Baptiste Lamarck, 1744 - 1829, French naturalist, is remembered for his evolutionary work and in particular for his now discredited theory of the inheritance of acquired characteristics. He proposed that changes taking place in life (prior to breeding, evidently) due to the effect of environment or the over- or under-use of particular organs are preserved by reproduction to new individuals which arise. Darwin's work however showed that the primary principle of evolution is selection, and Mendel demonstrated the mechanisms of genetic selection. Lamarck's theory was therefore abandoned, although very recently it has begun to seem that some of the mechanisms of genetic inheritance at the level of DNA may be open to change during the lifetime of an individual.