The development of Darwin's theory : natural history, natural theology, and natural selection, 1838-1859 / Dov Ospovat.

  • Ospovat, Dov.
Date:
1995, ©1981
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Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: The development of Darwin's theory : natural history, natural theology, and natural selection, 1838-1859 / Dov Ospovat. Source: Wellcome Collection.

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    Notes to pp. 177~9 groups to grow large and range widely: genera which are not typical are only rendered so by the extinction of allied genera, & that implies they are less adapted than other groups of genera to their world & therefore one might expect they would be less widely distributed (DAR 205.5:97, dated March 31, 1844). Similar statements are scattered throughout the Darwin MSS for this period. 28 DAR 205.9:303-4, dated November 1854. This is published by Robert C. Staufifer in Natural Selection, pp. 581-3. Stauffer's transcription contains a number of errors, at least three of which affect the sense of the note (I intend no disparagement of his monumental job of editing Natural Selection). Darwin's sheets of calculations show that by local he meant genera confined to one of the five great regions into which he divided the world, e.g., America, whole. 29 See Chapter 4, pp. 103-4, 108-9. 30 MLD, 1:82-8 (the correct dates of these two letters to Hooker are November 15, 1854, and December 11, 1854); DAR 205.5:147, dated November 1854. Darwin was anxious to establish his own explanation of fewness of species in aberrant genera as an alternative to a plausible creationist account: A creationist might say the fact of aberrance shows that they differ from common form, ie form adapted to commonest circumstances, & therefore it is self-evident they w* not be likely to have many species created on such type. Quite sufficient explanation. But it is necessary for me to account for fewness of species, after having shown such to be the case (DAR 205.9:310). 31 Most of the calculations are in DAR 205.9. Some of the conclusions from them were later added to Theoretical Geograph. Distrib. and have been published by Staufifer in Natural Selection, p. 583. 32 DAR 205.5:147, dated November 1854. 33 Essay of 1844, pp. 196-7. 34 The increasing genera are in my notions genera with close species (DAR 205.g:304v; published by Stauffer in Natural Selection, p. 583). 35 В notebook, p. 149. 36 In genera containing many species, the individual species stand much closer together than in poor genera (DAR 73:118). See Natural Selection, p. 93, OR LLD, 1:460. Darwin's account of his reaction to Fries {Natural Selection, pp. 93, 145-7) is colored by hindsight; the problem he was working on in 1855 was not to prove that varieties are incipient species, but rather to explain classification. 37 Natural Selection, pp. 146-8. 38 Ibid., pp. 93, 145-8. 39 Here for flavor are two extracts from Darwin's sheets of calculations: 1. (based on Alexandre Boreau, Flore du Centre de la France, 2 vols. [Paris, 1840]): of the 413 genera, 100 have one or more species with vars. & these 100 genera include 536 species, so they have on average 5.36. The remaining 313 (with no species having vars. have consequently (1156 — 536) 620 species, or on an average of only 1.98 species to each genus (DAR 15.2:4). 2. (based on Asa Gray's MS with close species marked): 266