Page:Popular Science Monthly Volume 75.djvu/456

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452
THE POPULAR SCIENCE MONTHLY

THE WORLD OF LIFE AS VISUALIZED AND INTERPRETED BY DARWINISM[1]
By ALFRED RUSSEL WALLACE, Esq., O.M., D.C.L., LL.D., F.R.S.

THE lecturer began by stating, that, although the theory of Darwinism is one of the most simple of comprehension in the whole range of science, there is none that is so widely and persistently misunderstood. This is the more remarkable, on account of its being founded upon common and universally admitted facts of nature, more or less familiar to all who take any interest in living things; and this misunderstanding is not confined to the ignorant or unscientific, but prevails among the educated classes, and is even found among eminent students and professors of various departments of biology.

Darwinism is almost entirely based upon these external facts of nature, the close observation and description of which constituted the old-fashioned "naturalists," and it is the specialization in modern science that has led to the misunderstanding referred to. Those who have devoted years to the almost exclusive study of anatomy, physiology or embryology, and that equally large class, who make the lower forms of life (mostly aquatic) the subject of microscopical investigation, are naturally disposed to think that a theory which can dispense with all their work (though often strikingly supported by it), can not be so important and far-reaching as it is found to be.

 

Numbers, Variety and Intermingling of Life-forms

Coming to the first great group of facts upon which Darwinism rests, the lecturer calls attention to the great number of distinct species both of vegetable and animal life found even in our own very limited and rather impoverished islands, as compared with the more extensive areas. Great Britain possessed somewhat less than 2,000 species of flowering plants while many equal areas on the continent of Europe have twice the number. The whole of Europe contains 9,000 species, and the world 136,000 species already described; but the total number, if the whole earth were as well known as Europe, would be almost certainly more than double that number or about a quarter of a million species. The following table, showing how much more crowded are the species in small than in large areas, was exhibited on the wall. It affords an excellent illustration of the fact of the great intermingling of species, so that large numbers are able lb live in close contact with other, usually very distinct, species.

 
  1. Abstract of a lecture before the Royal Institution of Great Britain.