On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
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Página 5
... developed being or elaborately constructed organ ; secondly , the subject of Instinct , or the mental powers of animals ; thirdly , Hybridism , or the in- fertility of species and the fertility of varieties when intercrossed ; and ...
... developed being or elaborately constructed organ ; secondly , the subject of Instinct , or the mental powers of animals ; thirdly , Hybridism , or the in- fertility of species and the fertility of varieties when intercrossed ; and ...
Página 20
... developed crop , which it glories in inflating , may well excite astonishment and even laughter . The turbit has a ... develop- ment of the bones of the face in length and breadth and curvature differs enormously . The shape , as well as ...
... developed crop , which it glories in inflating , may well excite astonishment and even laughter . The turbit has a ... develop- ment of the bones of the face in length and breadth and curvature differs enormously . The shape , as well as ...
Página 23
... developed . Moreover , when two birds belonging to two distinct breeds are crossed , neither of which is blue or has any of the above - specified marks , the mongrel offspring are very apt suddenly to acquire these characters ; for ...
... developed . Moreover , when two birds belonging to two distinct breeds are crossed , neither of which is blue or has any of the above - specified marks , the mongrel offspring are very apt suddenly to acquire these characters ; for ...
Página 36
... developed in some slight degree in an unusual manner , or a pouter till he saw a pigeon with a crop of somewhat unusual size ; and the more abnormal or unusual any character was when it first appeared , the more likely it would be to ...
... developed in some slight degree in an unusual manner , or a pouter till he saw a pigeon with a crop of somewhat unusual size ; and the more abnormal or unusual any character was when it first appeared , the more likely it would be to ...
Página 114
... developed , have now become extinct . Looking still more remotely to the future , we may predict that , owing to the continued and steady in- crease of the larger groups , a multitude of smaller groups will become utterly extinct , and ...
... developed , have now become extinct . Looking still more remotely to the future , we may predict that , owing to the continued and steady in- crease of the larger groups , a multitude of smaller groups will become utterly extinct , and ...
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Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence 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 land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely