THE SPECIES CONCEPT 
The earliest work of the systematists emphasized the simi- 
larities of individuals within species and the sharp distinc- 
tions between individuals of diverse species. This view was 
an inheritance from man’s primitive knowledge of plants and 
animals, and one which, bolstered by a widespread misinter- 
pretation of the doctrine of the uniformity of nature, is still 
widely held outside of scientific circles today. 
As the facilities for the more careful examination of indi- 
viduals were developed early in the last century, scientific 
emphasis was shifted to the fact that no two individuals are 
exactly alike, and the species problem resolved itself into a 
search for the factors of evolution. As a direct result of 
those investigations there has developed a growing conviction 
that individuals are the only realities in nature, and an agree- 
ment that species are only convenient concepts originating and 
ending in the minds of scientists. This is the basis of recent 
demands that we return to what is, curiously, called the 
Linnean species, it being argued that that was as near reality 
as any present-day concept, and an article far more ready for 
the use of those who are not taxonomic specialists. Taxon- 
omists have contributed little to the resolution of this con- 
fusion, for many of them are bewildered at the array of 
geographic variants and transition zone hybrids which have 
recently become available particularly from our own continent, 
and species are frankly defined in the codes as concepts that 
may be standardized and established by quasi-legal verbiage. 
One wonders to what extent this confusion as to the nature 
of species has delayed our understanding of the origin of 
species. Perhaps it is this confusion which leaves us without 
a convincing reply for the fundamentalists who insist that 
data from the evolution of domesticated plants and animals 
and from laboratory genetics may explain the origin of 
varieties but not of species. There is a peculiarly hollow ring 
to our statement that varieties are incipient species and that 
the evolution of species is too slow a process for human 
observation. Moreover, the illogical sequence in most of our 
texts, where the evolution materials are followed by the data 
of heredity, is some evidence that the geneticists do not per- 
ceive the application of their laboratory findings to species 
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