Darwinism: An Exposition of the Theory of Natural Selection, with Some of Its Applications, Объемы 1-2Macmillan, 1889 - Всего страниц: 494 |
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Стр. xi
... crossing and change of conditions - Remarks on the facts of hybridity - Sterility due to changed conditions and usually correlated with other characters— Correlation of colour with constitutional peculiarities - The isolation of ...
... crossing and change of conditions - Remarks on the facts of hybridity - Sterility due to changed conditions and usually correlated with other characters— Correlation of colour with constitutional peculiarities - The isolation of ...
Стр. 33
... crossed Kentucky River , at the town of Frankfort , at which time the living torrent above my head seemed as numerous and as extensive as ever . Long after this I observed them in large bodies that continued to pass for six or eight ...
... crossed Kentucky River , at the town of Frankfort , at which time the living torrent above my head seemed as numerous and as extensive as ever . Long after this I observed them in large bodies that continued to pass for six or eight ...
Стр. 52
... crossing them , and the white patch near the end of the outer tail- feathers are also extremely liable to variation in respect to their extent and the number of feathers to which , in the same species , these markings extend . " It is ...
... crossing them , and the white patch near the end of the outer tail- feathers are also extremely liable to variation in respect to their extent and the number of feathers to which , in the same species , these markings extend . " It is ...
Стр. 85
... crossing and feeding in the case of animals , and to improved cultivation in the case of plants . Crossing is occasionally used in order to obtain a combination of qualities found in two distinct breeds , and also because it is found to ...
... crossing and feeding in the case of animals , and to improved cultivation in the case of plants . Crossing is occasionally used in order to obtain a combination of qualities found in two distinct breeds , and also because it is found to ...
Стр. 88
... crossed and improved by selection , 1 These facts are taken from Darwin's Domesticated Animals and Cultivated Plants , vol . i . pp . 359 , 360 , 392-401 ; vol . ii . pp . 231 , 275 , 330 . our existing dogs have descended . But this ...
... crossed and improved by selection , 1 These facts are taken from Darwin's Domesticated Animals and Cultivated Plants , vol . i . pp . 359 , 360 , 392-401 ; vol . ii . pp . 231 , 275 , 330 . our existing dogs have descended . But this ...
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abundant adapted adduced allied species America amount animals and plants appears birds breed brilliant butterflies carnivora cause characters climate closely allied colours of animals common concealment conspicuous continued cross-fertilisation crossed curious Darwin dicotyledons distinct species domestic animals effects eggs enemies Eocene evidence extinct facts faculty favourable female fertile fertilisation flowers genera genus geological groups habits hybrids important increase individuals infertility inhabit insects intercrossing kind larvæ less living male mammalia mammals markings marsupials mimicry Miocene mode modified moths natural selection naturalists nests occur offspring organs Origin of Species peculiar pigeons Pliocene pollen portion possess probably produced Professor protectively coloured regions remarkable resemble seeds self-fertilisation Silurian similar specimens spots sterility structure struggle for existence supposed tail Tertiary theory tints tion toes trees tropical usually variability variation varied varieties vegetation warning colours whole wild wings Zealand
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Стр. 40 - When we reflect on this struggle, we may console ourselves with the full belief, that the war of nature is not incessant, that no fear is felt, that death is generally prompt, and that the vigorous, the healthy, and the happy survive and multiply.
Стр. 132 - I did not formerly consider sufficiently the existence of structures, which, as far as we can at present judge, are neither beneficial nor injurious; and this I believe to be one of the greatest oversights as yet detected in my work.
Стр. 38 - Starting, and looking half round, I saw the lion just in the act of springing upon me. I was upon a little height ; he caught my shoulder as he sprang, and we both came to the ground below together. Growling horribly close to my ear, he shook me as a terrier dog does a rat.
Стр. 38 - Growling horribly, close to my ear, he shook me as a terrier dog does a rat. The shock produced a stupor similar to that which seems to be felt by a mouse after the first shake of the cat. It caused a sort of dreaminess, in which there was no sense of pain nor feeling of terror, though I was quite conscious of all that was happening.
Стр. 31 - Not far from Shelbyville, in the State of Kentucky, about five years ago, there was one of these breeding places, which stretched through the woods in nearly a north and south direction ; was several miles in breadth, and was said to be upwards of forty miles in extent ! In this tract, almost every tree was furnished with nests, wherever the branches could accommodate them.
Стр. 32 - I was astonished at their appearance. They were flying with great steadiness and rapidity, at a height beyond gunshot, in several strata deep, and so close together, that could shot have reached them, one discharge could not have failed of bringing down several individuals. From right to left as far as the eye could reach, the breadth of this vast procession extended ; seeming everywhere equally crowded.
Стр. 31 - The ground was strewed with broken limbs of trees, eggs, and young squab pigeons, which had been precipitated from above, and on which herds of hogs were fattening. Hawks, buzzards, and eagles, were sailing about in great numbers, and seizing the squabs from...
Стр. 19 - Paraguay, the parasitic insects would probably increase; and this would lessen the number of the navel-frequenting flies — then cattle and horses would become feral, and this would certainly greatly alter (as indeed I have observed in parts of South America) the vegetation: this again would largely affect the insects; and this, as we have just seen in Staffordshire, the insectivorous birds, and so onwards in ever-increasing circles of complexity.
Стр. 9 - Darwin that he is the Newton of natural history, and that, just so surely as that the discovery and demonstration by Newton of the law of gravitation established order in place of chaos and laid a sure foundation for all future study of the starry heavens, so surely has Darwin, by his discovery of the law of natural selection and his demonstration of the great principle of the preservation of useful variations in the struggle for life, not only thrown a flood of light on the process of development...