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. 43
... markings , size , form , and texture or striation of the surface , even in specimens collected in the same locality . Thus , a French author has enumerated no less than 198 varieties of the common wood - snail ( Helix nemoralis ) ...
... markings , size , form , and texture or striation of the surface , even in specimens collected in the same locality . Thus , a French author has enumerated no less than 198 varieties of the common wood - snail ( Helix nemoralis ) ...
Стр. 51
... markings . difference in intensity of colour between the extremes of a series of fifty or one hundred specimens of any species , collected at a single locality , and nearly at the same season of the year , is often as great as occurs ...
... markings . difference in intensity of colour between the extremes of a series of fifty or one hundred specimens of any species , collected at a single locality , and nearly at the same season of the year , is often as great as occurs ...
Стр. 52
... markings so common on the wings and tails of birds , as the bars formed by the white tips of the greater wing - coverts , the white patch occasionally present at the base of the primary quills , or the white band crossing them , and the ...
... markings so common on the wings and tails of birds , as the bars formed by the white tips of the greater wing - coverts , the white patch occasionally present at the base of the primary quills , or the white band crossing them , and the ...
Стр. 84
... markings of the flowers , or in the size , form , colour , or flavour of the fruit . These differences are usually small , but are yet easily seen , and in their extremes are very considerable ; and they have this important quality ...
... markings of the flowers , or in the size , form , colour , or flavour of the fruit . These differences are usually small , but are yet easily seen , and in their extremes are very considerable ; and they have this important quality ...
Стр. 113
... markings or brilliant colours , which serve as a sign of inedibility and prevent their being needlessly attacked . This , however , is a portion of the very large sub- ject of organic colour and marking , which will be fully dis- cussed ...
... markings or brilliant colours , which serve as a sign of inedibility and prevent their being needlessly attacked . This , however , is a portion of the very large sub- ject of organic colour and marking , which will be fully dis- cussed ...
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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...