The Descent of Man, and Selection in Relation to SexDarwin, Charles
History
The Descent of Man, and Selection in Relation to Sex
Darwin, Charles
Evolution (Biology); Human beings -- Origin; Sex differences; Sexual dimorphism (Animals); Sexual selection in animals
After the foregoing statements made by such high authorities, it would
be superfluous on my part to give a number of borrowed details, shewing
that the embryo of man closely resembles that of other mammals. It may,
however, be added, that the human embryo likewise resembles certain low
forms when adult in various points of structure. For instance, the
heart at first exists as a simple pulsating vessel; the excreta are
voided through a cloacal passage; and the os coccyx projects like a
true tail, “extending considerably beyond the rudimentary legs.” (16.
Prof. Wyman in ‘Proceedings of the American Academy of Sciences,’ vol.
iv. 1860, p. 17.) In the embryos of all air-breathing vertebrates,
certain glands, called the corpora Wolffiana, correspond with, and act
like the kidneys of mature fishes. (17. Owen, ‘Anatomy of Vertebrates,’
vol. i. p. 533.) Even at a later embryonic period, some striking
resemblances between man and the lower animals may be observed.
Bischoff says that “the convolutions of the brain in a human foetus at
the end of the seventh month reach about the same stage of development
as in a baboon when adult.” (18. ‘Die Grosshirnwindungen des Menschen,’
1868, s. 95.) The great toe, as Professor Owen remarks (19. ‘Anatomy of
Vertebrates,’ vol. ii. p. 553.), “which forms the fulcrum when standing
or walking, is perhaps the most characteristic peculiarity in the human
structure;” but in an embryo, about an inch in length, Prof. Wyman (20.
‘Proc. Soc. Nat. Hist.’ Boston, 1863, vol. ix. p. 185.) found “that the
great toe was shorter than the others; and, instead of being parallel
to them, projected at an angle from the side of the foot, thus
corresponding with the permanent condition of this part in the
quadrumana.” I will conclude with a quotation from Huxley (21. ‘Man’s
Place in Nature,’ p. 65.) who after asking, does man originate in a
different way from a dog, bird, frog or fish? says, “the reply is not
doubtful for a moment; without question, the mode of origin, and the
early stages of the development of man, are identical with those of the
animals immediately below him in the scale: without a doubt in these
respects, he is far nearer to apes than the apes are to the dog.”
RUDIMENTS.
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