The Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for LifeD. Appleton, 1904 - 435 páginas |
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Página 52
... allied forms , and these alone bear on the question . If monstrous forms of this kind ever do appear in a state of nature and are capable of reproduction ( which is not always the case ) , as they occur rarely and singularly , their ...
... allied forms , and these alone bear on the question . If monstrous forms of this kind ever do appear in a state of nature and are capable of reproduction ( which is not always the case ) , as they occur rarely and singularly , their ...
Página 56
... allied dimorphic species inhabiting an- other part of the Malay archipelago . Thus also with ants , the several worker - castes are generally quite distinct ; but in some cases , as we shall hereafter see , the castes are connected ...
... allied dimorphic species inhabiting an- other part of the Malay archipelago . Thus also with ants , the several worker - castes are generally quite distinct ; but in some cases , as we shall hereafter see , the castes are connected ...
Página 60
... likewise necessarily occurs with closely allied organisms , which inhabit distinct conti- nents or islands . When , on the other hand , an animal or plant ranges over the same continent , or inhabits 60 [ CHAP . II . DOUBTFUL SPECIES .
... likewise necessarily occurs with closely allied organisms , which inhabit distinct conti- nents or islands . When , on the other hand , an animal or plant ranges over the same continent , or inhabits 60 [ CHAP . II . DOUBTFUL SPECIES .
Página 64
... allied forms . But if his ob- servations be widely extended , he will in the end gen- erally be able to make up his own mind : but he will succeed in this at the expense of admitting much varia- tion , and the truth of this admission ...
... allied forms . But if his ob- servations be widely extended , he will in the end gen- erally be able to make up his own mind : but he will succeed in this at the expense of admitting much varia- tion , and the truth of this admission ...
Página 73
... allied to other species as to be of doubtful value : these 63 reputed species range on an average over 6.9 of the prov- inces into which Mr. Watson has divided Great Britain . Now , in this same Catalogue , 53 acknowledged varie- ties ...
... allied to other species as to be of doubtful value : these 63 reputed species range on an average over 6.9 of the prov- inces into which Mr. Watson has divided Great Britain . Now , in this same Catalogue , 53 acknowledged varie- ties ...
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Términos y frases comunes
adapted affinities allied species America ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common continent crossed crustaceans degree developed difficulty distinct species domestic doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation 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 males mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs parent peculiar perfect pigeon pistil pollen present principle probably produced progenitor quadrupeds ranked remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed swimbladder tend theory tion trees variability variations varieties vary whilst whole wings young