Evolution / by Patrick Geddes and J. Arthur Thomson.

  • Patrick Geddes
Date:
[1911?]
Catalogue details

Licence: Public Domain Mark

Credit: Evolution / by Patrick Geddes and J. Arthur Thomson. Source: Wellcome Collection.

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    obscure. A practical study of the species of plants and animals, and of the way one category of classification includes those be¬ neath it—classes, orders; orders, families; families, genera; genera, species; species, varieties; and varieties, individuals—gives us “ an impression of affiliation ” which we do not get from a classification of rocks or other inanimate objects. It is impossible not to feel in biological classification the suggestion of pedigrees and heraldry. Vestigial Structures.—Both in plants and animals it is common to find minute and more or less useless representatives of organs which are well developed and functional in related forms. It is impossible for us nowadays to keep from calling these structures vestigial (a better term than rudimentary, which should be kept for what is incipient), and from regard¬ ing them as the tell-tale evidences of remote ancestry. Darwin compared them to the unsounded letters in many words, such as the 44 o ” in leopard, the 44 b ” in doubt, the 44 g ” in reign, which are quite functionless, but tell us something about the history of these words. Every one is familiar with the numerous functionless flaps and buttons in clothing which once had a meaning they have now lost. Similar 44 vestigial structures 55 or 44 sur-