"--Science_, September
3, 1915.]
V
Let us sum up the situation. We began this chapter with the question,
Have new kinds of plants and animals originated in modern times
comparable in all essential respects with the idea of true species?
The answer of modern science is reluctantly obtained, but it is a
negative. De Vries and others have indeed originated new kinds that were
loudly hailed as new species, and are doubtless as deserving of specific
rank as many already listed for years in the treatises of specialists.
Indeed there is every reason to believe that almost countless numbers of
our taxonomic species have originated from common ancestral originals.
But as these so-called species are now known to be freely or moderately
cross fertile with other related species, their hybrids following the
ordinary laws of Mendelian inheritance, we see that they are not true
species but mere analytic varieties.
In short, we now know that our taxonomic classifications have been
marked off on altogether too narrow lines. This has tended greatly to
confuse the question at issue. But from our enlarged views of the laws
and nature of heredity and variation, as well as from the original
intent of the term _species_ as defined by the great scientist who
originated it, the verdict of an impartial investigator must be that we
have never seen a new species originate by any natural or artificial
method since the dawn of scientific observation.
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