Autobiografie S. 68 f. Darwin Online, abgerufen am 23. Juli 2009: „Upon the whole the three years which I spent at Cambridge were the most joyful in my happy life; for I was then in excellent health, and almost always in high spirits.“
Francis Darwin: The Life and Letters of Charles Darwin. 3 Bände, John Murray, London 1887, Bd. 1, S. 163 (online).
Paul H. Barrett: The Sedgwick-Darwin geologic tour of North Wales. In: Proceedings of the American Philosophical Society. Bd. 118, Nr. 2, 19. April 1974, S. 146–164 online
Autobiografie S. 120. Darwin Online, abgerufen am 23. Juli 2009: „[…] it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work; […]“
Autobiographie S. 94. Darwin Online, abgerufen am 27. Juli 2009: „The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an Agnostic.“
Charles Darwin an Joseph Dalton Hooker, 11. Januar 1844, Brief 729. The Darwin Correspondence Project, abgerufen am 23. Juli 2009: „At last gleams of light have come, & I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable.“
Joseph Dalton Hooker an Charles Darwin, 29. Januar 1844, Brief 734. The Darwin Correspondence Project, abgerufen am 23. Juli 2009: „There may in my opinion have been a series of productions on different spots, & also a gradual change of species. I shall be delighted to hear how you think that this change may have taken place, as no presently conceived opinions satisfy me on the subject.“
doi.org
J. R. Lucas: Wilberforce and Huxley: A Legendary Encounter. In: The Historical Journal. Bd. 22, Nr. 2, S. 313–330 (doi:10.1017/S0018246X00016848).
pbs.org
Theodosius Dobzhansky: Nothing in biology makes sense except in the light of evolution. In: American Biology Teacher. Bd. 35, 1973, S. 125–129. (online), abgerufen am 6. Juni 2008.
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Charles Darwin an Emma Darwin, 23. April 1851, Brief 1412. The Darwin Correspondence Project, ehemals im Original (nicht mehr online verfügbar); abgerufen am 29. Juli 2009: „My dear dearest Emma – I pray God Fanny’s note may have prepared you. She went to her final sleep most tranquilly, most sweetly at 12 oclock today.“ Charles Darwin an Erasmus Alvey Darwin, 25. April 1851, Brief 1416. The Darwin Correspondence Project, ehemals im Original (nicht mehr online verfügbar); abgerufen am 29. Juli 2009: „Will you be so kind as to get inserted as follows in Times & in any other one or two Papers of largest circulation. “At Malvern on the 23d inst; of Fever, Anne Elizabeth Darwin, aged ten years, eldest daughter of Charles Darwin Esq. of Down Kent.”—.“ Anmerkung: In seiner Autobiographie auf S. 97 schreibt Charles Darwin We have suffered only one very severe grief in the death of Annie at Malvern on April 24th, 1851, when she was just over ten years old. allerdings scheint diese Information falsch zu sein.
