On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle of LifeAppleton, 1864 - Всего страниц: 440 |
Результаты поиска по книге
Результаты 1 – 5 из 81
Стр. 6
... insects - Summary , 185 CHAPTER VIII . HYBRIDISM . Distinction between the sterility of first crosses and of hybrids - Sterility various in degree , not universal , affected by close interbreeding , removed by domestication- Laws ...
... insects - Summary , 185 CHAPTER VIII . HYBRIDISM . Distinction between the sterility of first crosses and of hybrids - Sterility various in degree , not universal , affected by close interbreeding , removed by domestication- Laws ...
Стр. 11
... insects under the bark of trees . In the case of the misseltoe , which draws its nourishment from certain trees , which has seeds that must be transported by certain birds , and which has flowers with separate sexes abso- lutely ...
... insects under the bark of trees . In the case of the misseltoe , which draws its nourishment from certain trees , which has seeds that must be transported by certain birds , and which has flowers with separate sexes abso- lutely ...
Стр. 47
... insect would have been variable in the same species ; I should have expected that changes of this nature could have ... insects are very far from uniform . Authors sometimes argue in a circle when they state that important organs CHAP ...
... insect would have been variable in the same species ; I should have expected that changes of this nature could have ... insects are very far from uniform . Authors sometimes argue in a circle when they state that important organs CHAP ...
Стр. 48
... insects , and sev- eral genera of Brachiopod shells . In most polymorphic genera some of the species have fixed and definite char- acters . Genera which are polymorphic in one country seem to be , with some few exceptions , polymorphic ...
... insects , and sev- eral genera of Brachiopod shells . In most polymorphic genera some of the species have fixed and definite char- acters . Genera which are polymorphic in one country seem to be , with some few exceptions , polymorphic ...
Стр. 50
... insects in North America and Europe , which differ very slightly from each other , have been ranked by one eminent naturalist as undoubted species , and by another as varieties , or , as they are often called , as geographical races ...
... insects in North America and Europe , which differ very slightly from each other , have been ranked by one eminent naturalist as undoubted species , and by another as varieties , or , as they are often called , as geographical races ...
Другие издания - Просмотреть все
The Origin of Species by Means of Natural Selection: Or, The ..., Том 1 Charles Darwin Полный просмотр - 1889 |
Часто встречающиеся слова и выражения
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 land larvæ 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
Популярные отрывки
Стр. 424 - 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. 63 - There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair.
Стр. 79 - I may be allowed to personify the natural preservation or survival of the fittest, cares nothing for appearances, except in so far as they are useful to any being. She can act on every internal organ, on every shade of constitutional difference, on the whole machinery of life. Man selects only for his own good: Nature only for that of the being which she tends.
Стр. 70 - I counted thirtytwo little trees ; and one of them, with twenty-six rings of growth, had during many years tried to raise its head above the stems of the heath, and had failed. No wonder that, as soon as the land was enclosed, it became thickly clothed with vigorously growing young firs. Yet the heath was so extremely barren and so extensive that no one would ever have imagined that cattle would have so closely and effectually searched it for food. Here we see that cattle absolutely determine the...
Стр. 169 - 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.
Стр. 63 - Hence as more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life.
Стр. 167 - 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.
Стр. 378 - 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 'Nature of Limbs.
Стр. 187 - Under changed conditions of life, it is at least possible that slight modifications of instinct might be profitable to a species; and if it can be shown that instincts do vary ever so little, then I can see no difficulty in natural selection preserving and continually accumulating variations of instinct to any extent that was profitable. It is thus, as I believe, that all the most complex and wonderful instincts have originated.
Стр. 165 - I can see no difficulty in a race of bears being rendered, by natural selection, more and more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale.