On the Origin of Species by Means of Natural Selection; Or, The Preservation of Favoured Races in the Struggle for LifeD. Appleton, 1861 - 440페이지 |
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5 페이지
... common species vary most - Species of the larger genera in any country vary more than the species of the smaller genera - Many of the species of the larger genera resemble varieties in being very closely , but unequally , related to ...
... common species vary most - Species of the larger genera in any country vary more than the species of the smaller genera - Many of the species of the larger genera resemble varieties in being very closely , but unequally , related to ...
6 페이지
... common parent - Explains the Grouping of all organic beings , · • 77 CHAPTER V. LAWS OF VARIATION . Effects of external conditions - Use and disuse , combined with natural selection ; organs of flight and of vision - Acclimatisation ...
... common parent - Explains the Grouping of all organic beings , · • 77 CHAPTER V. LAWS OF VARIATION . Effects of external conditions - Use and disuse , combined with natural selection ; organs of flight and of vision - Acclimatisation ...
23 페이지
... common camel , prevented their domestication ? I cannot doubt that if other animals and plants , equal in number to our domes- ticated productions , and belonging to equally diverse classes and countries , were taken from a state of ...
... common camel , prevented their domestication ? I cannot doubt that if other animals and plants , equal in number to our domes- ticated productions , and belonging to equally diverse classes and countries , were taken from a state of ...
24 페이지
... common wild Indian fowl ( Gallus bankiva ) . In regard to ducks and rabbits , the breeds of which differ considerably from each other in structure , I do not doubt that they all have descended from the common wild duck and rabbit . The ...
... common wild Indian fowl ( Gallus bankiva ) . In regard to ducks and rabbits , the breeds of which differ considerably from each other in structure , I do not doubt that they all have descended from the common wild duck and rabbit . The ...
26 페이지
... common tumbler has the singular and strictly inherited habit of flying at a great height in a compact flock , and tumbling in the air head over heels . The runt is a bird of great size , with long , massive beak and large feet ; some of ...
... common tumbler has the singular and strictly inherited habit of flying at a great height in a compact flock , and tumbling in the air head over heels . The runt is a bird of great size , with long , massive beak and large feet ; some of ...
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accumulated adapted affinities allied species America amount ancient animals appear become bees believe birds breeds cause cells characters cirripedes climate closely allied colour continuous crossed crustaceans degree difficulty distinct species disuse divergence domestic doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing intermediate larvæ laws less living look male mammals manner migration modification modified descendants natural selection naturalists nearly nest offspring organic organisation perfect pigeons pistil plants pollen present probably produced progenitor ranked reciprocal crosses remarked resemble rudimentary seeds seems sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation varieties vary whole widely
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9 페이지 - After five years' work I allowed myself to speculate on the subject, and drew up some short notes; these I enlarged in 1844 into a sketch of the conclusions, which then seemed to me probable: from that period to the present day I have steadily pursued the same object. I hope that I may be excused for entering on these personal details, as I give them to show that I have not been hasty in coming to a decision.
76 페이지 - 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.
171 페이지 - If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.
9 페이지 - Beagle,' as naturalist, I was much struck with certain facts in the distribution of the organic beings inhabiting South America, and in the geological relations of the present to the past inhabitants of that continent.
70 페이지 - Firs on the distant hill-tops ; within the last ten years large spaces have been enclosed, and self-sown firs are now springing up in multitudes, so close together that all cannot live. When I ascertained that these young trees had not been sown or planted, I was so much surprised at their numbers that I went to several points of view, whence I could examine hundreds of acres of the unenclosed heath, and literally I could not see a single Scotch Fir, except the old planted clumps.
72 페이지 - Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice." Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!
72 페이지 - Newman, who has long attended to the habits of humble-bees, believes that " more than two-thirds of them are thus destroyed all over England.
169 페이지 - To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.
423 페이지 - Hereafter we shall be compelled to acknowledge that the only distinction between species and well-marked varieties is, that the latter are known, or believed to be connected at the present day by intermediate gradations whereas species were formerly thus connected.
212 페이지 - This difficulty, though appearing insuperable, is lessened, or, as I believe, disappears, when it is remembered that selection may be applied to the family, as well as to the individual, and may thus gain the desired end. Thus, a well-flavoured vegetable is cooked, and the individual is destroyed; but the horticulturist sows seeds of the same stock, and confidently expects to get nearly the same variety; breeders of cattle wish the flesh and fat to be well marbled together; the animal has been slaughtered,...