RECORD: Darwin, C. R. 1863.01.04. An animal, say, becoming adapted for aquatic life. CUL-DAR205.7.164. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 1.2023. RN1
NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volume CUL-DAR205.7 contains notes on hybridism, sterility and pigeons.
Jan 4 1863 An animal, say, becoming adapted for aquatic life & surrounded by so many of its parent terrestrial forms, that in course of few generations all such vars, chanced to get crossed by them; would be dragged back from its favourable variation.
But if a variation arose, which was sterile with ordinary form, then although ever so large a proportion was united with ordinary form & was ultimately lost by sterility; yet if ever so few united with similar form, these would be kept pure; but then chances are supposed that they would unite with ordinary form & so would be lost by sterility. It will not do. Then sterility must supervene for being kept close to uniform conditions of life for ages.
If sexual disinclination supervened all would go well; but then why does sterility supervene, & why in Hybrid & not always in first cross — — will not do. —
N. B Sexual disinclination must be an acquired instinct: for how else could it arise?
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 9 May, 2023