Showing 61–80 of 188 items
Reports work on sexual selection. Problems with the relative numbers of the two sexes and polygamy. Asks ARW’s help with several questions on polygamous birds.
Responds to CD’s queries on polygamy in birds and orang.
Discusses sexual selection and secondary characters; colours and sexual preference.
Expresses his admiration for Pangenesis; it is superior to Herbert Spencer’s theory.
ARW differs somewhat with CD’s chapter on causes of variability [ch. 22 in Variation]. Thinks several of CD’s arguments are unsound.
Briefly discusses how natural selection might aid in producing sterility between allied species.
Pleased by ARW’s response to Pangenesis.
On negative reception by his friends.
Further argument concerning sterility and natural selection.
Polygamy and sexual selection.
Protection.
Offers enclosure demonstrating that natural selection could produce sterility of hybrids.
More on Pangenesis and the inadequacy of H. Spencer’s approach.
On critical exchanges at the Linnean Society on natural selection and mimicry.
Roland Trimen’s paper on South African mimetic butterflies ["On some remarkable mimetic resemblances among African butterflies", Trans. Linn. Soc. Lond. 26 (1870): 497–523; read 5 Mar 1868].
Coloration of butterflies; brilliantly coloured females.
Commends CD on his paper on specific differences in Primula [J. Proc. Linn. Soc. Lond. (Bot.) 10 (1869): 437–54; reprinted and revised in Forms of flowers] as a test-case proving origin of real species.
On his Primula paper for the Linnean Society ["On the specific difference between Primula veris, Brit. Fl. (var. officialis, Linn.), P. vulgaris, Brit. Fl. var. acaulis, Linn.), and P. elatior, Jacq.; and on the hybrid nature of the common oxlip; with supplementary remarks on naturally produced hybrids of the genus Verbascum", [officinalis!?] J. Linn. Soc. Lond. (Bot.) 10 (1869): 437–54].
Peacocks and sexual selection.
ARW’s sterility argument has driven CD’s sons half-mad.
On sterility of natural species and natural selection. Closely allied forms from adjacent islands offer best chance of finding good species fertile inter se.
Problem of minute variations and sexual selection.
On problem of sterility, CD cannot persuade himself that it has been gained by natural selection.
On sexual selection and minute variations, he tends to agree with ARW. Sends George Darwin’s notes on ARW’s argument.
Returns George Darwin’s criticisms of his notes on sterility and sends further notes in reply. Since there are degrees of sterility between varieties, "is it not probable that natural selection can accumulate these variations?" Varieties that are adapted to new conditions could then survive and form new species without being isolated.
There are so many doubtful points on the problems relating to sterility that they will never agree.
More on the "terrible problem" of natural selection and sterility. CD’s reasons for disagreeing with ARW. CD analyses and answers ARW in detail in defence of his conclusion that sterility cannot be increased through natural selection.
If CD is not convinced by his notes on sterility, ARW has little doubt that he is wrong. In fact he was only half-convinced by his own arguments.
Modifies his first proposition [a species varies occasionally in two directions, but owing to free inter-crossing the variations never increase] and further discusses the subject.
Encloses Berthold Seemann’s notes on flora of the Hawaiian Islands. Presence of European alpine species in Hawaiian volcanoes is a "hard nut" for geographical distribution [but see ARW’s Island life (1880), p. 323].
Warns ARW of dubious character of list of European alpine genera and species in volcanoes of Hawaii. Problems of geographical distribution in oceanic islands.
Admires ARW’s "Theory of birds’ nests" [J. Travel & Nat. Hist. 1 (1868): 73].
Discusses their respective views on birds’ nests, sexual selection, and protection.
Asks why, if brilliant colours of female butterflies are result of protective mimicry, do not males become equally brilliant? CD believes variation in females alone accounts for it, rather than protection.
Various topics related to sexual selection: sexual differences, sexual preferences, coloration.
More on CD’s objections to ARW’s views on protection and natural selection.
Sexual selection.
Answers CD’s objection [see 6121 and 6146] about sexual differences and protective colouring. Summarises his theory of colour in nature.
Criticism of ARW for too little esteem of the role of sexual selection as agent in giving colour.
Response to other topics.
The problem of sterility, and its relation to natural selection.
George Bentham’s support of Darwinism.
