-
14. A Man of Enlarged Curiosity
- Johns Hopkins University Press
- Chapter
- Additional Information
[ 72 ] fourteen v A Man of Enlarged Curiosity Darwin DiD not QuietLy retire after publication of The Origin, although he suffered greatly as his health continued to decline. Instead, he turned his attention to botany. By studying the morphology and anatomy of flowers , especially orchids, Darwin discovered that nearly all parts of a flower are adapted to allow pollination by insects (as opposed to the creationist belief that flowers were designed to provide beauty for humans). He published On theVarious Contrivances by which Orchids are Fertilized by Insects in 1862. In this book, he expressed amazement at an orchid (Angraecum sesquipedale) from Madagascar that has an 11½ inch long, whiplike nectary (a gland that secretes nectar) and speculated that there must be a moth in that island with a proboscis (a flexible snoutlike body part used to extract nectar) capable of reaching something this deep. It was not until 1903 that entomologists described a giant hawk-moth from Madagascar with such an astonishing proboscis; they named it Xanthopan morganii praedicta in honor of Darwin’s prediction. Darwin was greatly influenced by Asa Gray, his American botanist friend and correspondent at Harvard University, who had written a paper on the coiling tendrils of plants. Darwin conducted experiments on this subject in his greenhouse at Down. The Movements and Habits of Climbing Plants was published by the Linnean Society in 1865 and reissued as a book [ 73 ] in 1875 by his publisher, John Murray. Darwin’s experiments were often ingenious, and carried out meticulously to control all factors. In fact, because of his botanical experiments, the word “control” entered the literature of experimental biology. Next, he gathered together his vast database of facts and observations on domestication and breeding, especially his own work with pigeons. Some data were already organized as chapters in his unpublished “Natural Selection” big book, and this material was published in 1868 in his two-volume The Variation of Animals and Plants under Domestication. Herbert Spencer’s phrase “survival of the fittest” was first used by Darwin in Variation, and he repeated it in the fifth edition of The Origin in 1869. Variation also elaborated on Darwin’s view of heredity. He suggested, erroneously, that particles from the body accumulate in the ovaries and testes and that these “gemmules” are transmitted to form offspring and account for inherited characteristics. The Descent of Man and Selection in Relation to Sex was published in 1871. In The Descent, Darwin used the term Greenhouse at Down where Darwin conducted his botanical experiments . (Author’s photograph, 1974) [54.160.244.62] Project MUSE (2024-03-19 03:43 GMT) [ 74 ] “evolution” for the first time in its modern sense. Later, in the sixth and final edition of The Origin in 1872, he more fully discussed his “transmutation” theory in terms of “evolution .” The Descent is essentially two works. The first third is a continuation of The Origin, as applied to man. There were virtually no human fossils known at this time, except for a few confusing Neanderthal bones for which there had not yet been a good explanation. No australopithecines (ape-men, or “missing links”) were known. Yet Darwin correctly reasoned, on biogeographical grounds, that Africa was the cradle of human evolution. This has since been confirmed by an abundance of Australopithecus species found only in Africa and by DNA data. The brilliance of his reasoning is shown in the following quote from The Descent of Man: “In each great region of the world the living mammals are closely related to the extinct species of the same region. It is therefore probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee; and as these two species are now man’s nearest allies, it is somewhat more probable that our early progenitors lived on the African continent than elsewhere.” The second two-thirds of the book, sexual selection, explained the development of secondary sexual characters in one sex by the preferences of the other sex—for example, peahens choosing to mate with peacocks with elaborate tails. The Descent re-ignited the volatile debate begun by The Origin, because it clearly stated what The Origin had only hinted at: that humankind was directly descended from animals. Darwin himself was relatively unaffected by the public controversy , remaining secluded at Down and continuing to gather evidence to support his theory. After finishing The Descent, Darwin began drawing together all his observations on emotion, including the notes he made when his...