Charles Darwin's Works: The origin of species by means of natural selection...with additions and corrections from 6th and last English edD. Appleton, 1896 |
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Стр. 17
Charles Darwin. that species have been endowed with sterility simply to prevent their becoming confounded in nature ? I think not . For why should the sterility be so extremely different in degree , when various species are crossed , all ...
Charles Darwin. that species have been endowed with sterility simply to prevent their becoming confounded in nature ? I think not . For why should the sterility be so extremely different in degree , when various species are crossed , all ...
Стр. 24
... become nearly mature , but the young chickens had been unable to break through the shell . Of the chickens which ... becoming acquainted with these facts , I was unwilling to believe in the frequent early death of hybrid embryos ; for ...
... become nearly mature , but the young chickens had been unable to break through the shell . Of the chickens which ... becoming acquainted with these facts , I was unwilling to believe in the frequent early death of hybrid embryos ; for ...
Стр. 28
... become widely or specifically different , produce hybrids which are almost always in some degree sterile . I am fully persuaded that this double parallelism is by no means an accident or an illusion . He who is able to explain why the ...
... become widely or specifically different , produce hybrids which are almost always in some degree sterile . I am fully persuaded that this double parallelism is by no means an accident or an illusion . He who is able to explain why the ...
Стр. 35
... become perfectly fertile together . With plants , so far is cultivation from giving a tendency towards sterility between distinct species , that in several well - authenticated cases already alluded to , certain plants have been ...
... become perfectly fertile together . With plants , so far is cultivation from giving a tendency towards sterility between distinct species , that in several well - authenticated cases already alluded to , certain plants have been ...
Стр. 36
... becomes in the highest degree improbable that similar conditions long - continued should likewise induce this ... become mutually infertile when crossed , but why this has so generally occurred with natural varieties , as soon as ...
... becomes in the highest degree improbable that similar conditions long - continued should likewise induce this ... become mutually infertile when crossed , but why this has so generally occurred with natural varieties , as soon as ...
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accumulated adapted admit adult affinity allied species ancient animals appear Archipelago arctic areas become beds believe birds breeds Cambrian changes characters classification climate closely allied common progenitor continent crustaceans degree deposited difficulty distant distinct species domestic doubt embryo Europe existing extinct fact faunas fertilised fertility flowers formations formerly forms fossil fresh-water Fritz Müller Gärtner genera genus geological record Glacial period groups of species habits hybrids hybrids produced important individuals inhabitants inherited insects instance intermediate intervals land larvæ less living mammæ mammals manner marine Marsupials migration modified descendants mongrels mountains natural selection naturalists nearly occur oceanic islands offspring organisation palæontologists paleozoic parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs seeds Silurian slight South America stage stamens sterility structure successive suppose terrestrial tertiary tion variations varieties whilst widely different
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Стр. 305 - There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
Стр. 304 - Judging from the past, we may safely infer that not one living species will transmit its unaltered likeness to a distant futurity. And of the species now living very few will transmit progeny of any kind to a far distant futurity...
Стр. 277 - That many breeds produced by man have to a large extent the character of natural species, is shown by the inextricable doubts whether many of them are varieties or aboriginally distinct species. There is no reason why the principles which have acted so efficiently under domestication should not have acted under nature.
Стр. 296 - I by no means expect to convince experienced naturalists whose minds are stocked with a multitude of facts all viewed, during a long course of years, from a point of view directly opposite to mine. ... [B]ut I look with confidence to the future, — to young and rising naturalists, who will be able to view both sides of the question with impartiality.
Стр. 293 - This has been effected chiefly through the. natural selection of numerous successive, slight, favourable variations; aided in an important manner by the inherited effects of the use and disuse of parts ; and in an* unimportant manner, that is in relation to adaptive structures, whether past or present, by the direct action of external conditions, and by variations which seem to us in our ignorance to arise spontaneously.
Стр. 302 - ... will no doubt become simpler when we have a definite object in view. We possess no pedigrees or armorial bearings ; and we have to discover and trace the many diverging lines of descent in our natural genealogies, by characters of any kind which have long been inherited.
Стр. 299 - I believe that animals have descended from at most only four or five progenitors, and plants from an equal or lesser number. " Analogy would lead me one step further, namely, to the belief that all animals and plants have descended from some one prototype. But analogy may be a deceitful guide.
Стр. 281 - ... increasing in size, for the world would not hold them, the more dominant groups beat the less dominant. This tendency in the large groups to go on increasing in size and diverging in character, together with the...
Стр. 304 - In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light will be thrown on the origin of man and his history.
Стр. 233 - Nothing can be more hopeless than to attempt to explain this similarity of pattern in members of the same class, by utility or by the doctrine of final causes. The hopelessness of the attempt has been expressly admitted by Owen in his most interesting work on the