On the Origin of Species: By Means of Natural Selection, Or, the Preservation of Favored Races in the Struggle for LifeAppleton, 1883 - Всего страниц: 458 |
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Стр. xiv
... forms in certain groups , and by the analogy of domestic produc- tions . With respect to the means of modification , he attributed something to the direct action of the physical conditions of life , something to the crossing of already ...
... forms in certain groups , and by the analogy of domestic produc- tions . With respect to the means of modification , he attributed something to the direct action of the physical conditions of life , something to the crossing of already ...
Стр. xx
... forms . In this same year , 1853 , Dr. Schaaffhausen published an ex- cellent pamphlet ( Verhand . des Naturhist . Vereins der Preuss . Rheinlands , ' & c . ) , in which he maintains the progressive develop- ment of organic forms on the ...
... forms . In this same year , 1853 , Dr. Schaaffhausen published an ex- cellent pamphlet ( Verhand . des Naturhist . Vereins der Preuss . Rheinlands , ' & c . ) , in which he maintains the progressive develop- ment of organic forms on the ...
Стр. 34
... forms of this kind ever do appear in a state of nature and are capable of reproduction ( which is not always the ... form , and thus their abnormal character would almost inevitably be lost . But I shall have to return in a future ...
... forms of this kind ever do appear in a state of nature and are capable of reproduction ( which is not always the ... form , and thus their abnormal character would almost inevitably be lost . But I shall have to return in a future ...
Стр. 36
... forms ; one of these has strong and differently shaped pincers , and the other has antennæ much more abundantly furnished with smelling - hairs . Although in most of these cases , the two or three forms , both with animals and plants ...
... forms ; one of these has strong and differently shaped pincers , and the other has antennæ much more abundantly furnished with smelling - hairs . Although in most of these cases , the two or three forms , both with animals and plants ...
Стр. 37
... forms always remove the difficulty . In very many cases , however , one form is ranked as a variety of another , not because the intermediate links have actually been found , but because analogy leads the observer to suppose either that ...
... forms always remove the difficulty . In very many cases , however , one form is ranked as a variety of another , not because the intermediate links have actually been found , but because analogy leads the observer to suppose either that ...
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adapted admit affinities allied species America analogous ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formations forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids important individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection slight South America stamens sterility structure struggle successive supposed theory tion variability variations varieties vary whilst whole wings young
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Стр. 65 - It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life.
Стр. 104 - The green and budding twigs may represent existing species, and those produced during former years may represent the long succession of extinct species. At each period of growth all the growing twigs have tried to branch out on all sides, and to overtop and kill the surrounding twigs and branches, in the same manner as species and groups of species have at all times overmastered other species in the great battle for life.
Стр. 57 - 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'.
Стр. 23 - ... that which enables the agriculturist not only to modify the character of his flock, but to change it altogether. It is the magician's wand, by means of which he may summon into life whatever form and mould he pleases.
Стр. 146 - 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. 50 - But a plant on the edge of a desert is said to struggle for life against the drought, though more properly it should be said to be dependent on the moisture.
Стр. 429 - These laws, taken in the largest sense, being Growth with reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life, and from use and disuse...
Стр. 104 - The limbs divided into great branches, and these into lesser and lesser branches, were themselves once, when the tree was young, budding twigs; and this connection of the former and present buds, by ramifying branches, may well represent the classification of all extinct and living species in groups subordinate to groups.
Стр. 425 - Nevertheless all living things have much in common, in their chemical composition, their cellular structure, their laws of growth, and their liability to injurious influences.
Стр. 2 - ... species had not been independently created, but had descended, like varieties, from other species. Nevertheless, such a conclusion, even if well founded, would be unsatisfactory, until it could be shown how the innumerable species inhabiting this world have been modified so as to acquire that perfection of structure and co-adaptation which justly excites our admiration.