HUMAN ORGANIC EVOLUTION: FACT OR FANCY? 



The outcome of selection usually is the better adaptability 

 of the organism to the environment. Experiments and many 

 observations have shown this to be the case. But adaptation 

 is rarely if ever perfect. However, adaptation seems to become 

 more perfect where the density of living forms and thus the 

 intensity of selection is greater, that is to say where the 

 number of individuals competing for the same ecological niche 

 is greater. On the other hand, where this pressure for selection 

 is low, there is then a tendency to develop more varieties. 

 One wonders if there is not an application to this also in 

 higher organisms when the decrease of the varieties of wild 

 animal forms is considered which yielded to highly adaptive 

 man. 



An example of selection which is fairly well documented 

 and which directly relates to man is the Rh positive and 

 negative blood group gene. If Rh negative and Rh positive 

 had equal frequencies in a population the action of selection 

 would be zero. If the incidence of the two genes is unequal, 

 the less frequent gene would be affected to a greater extent 

 than the more common gene, so that in the absence of other 

 influences, the less common gene would be eliminated. The 

 practically complete absence of the Rh negative gene in 

 Australian, Indonesian, Asiatic, and American Indian popu- 

 lations might suggest that selection already took place before 

 these populations left Asia. A similar sort of reasoning is 

 being applied to the problem of the distribution of the sickle 

 cell phenomenon in Africa, which eventually may help to shed 

 light on the mechanism of selection, especially as it pertains 

 to modern man. 20 



Eventually, perhaps the "racial" characters of man may be 

 better understood as to how they have been acquired by man 

 during this process of natural selection, such as skin color or 

 somatic type. Coon, Garn and Birdsell (1950) 21 have done 

 some work on this, but this has been contested, because man, 

 unlike lower animals, has a culture which permits him to 



^^ Cf. James V. Neel, "The Study of Natural Selection in Primitive and 

 Civilized Human Populations," Natural Selection in Man (J. N. 

 Spuhler, ed.), Detroit, 1958. pp. 43^72. 



^^ C. S, Coon, S. M. Gam, J. B. Birdsell, Races: A Study of the Problems 

 of Race Formation in Man, Springfield, 1950. See also Neel, op cit. 



47 



