The origin of species by means of natural selectionРипол Классик, 1929 - 454 páginas |
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Página 13
... crossed ofl'spring from a short-horned cow by a long-horned bull, the greater length of horn, though a peering late in life, is clearly due to the male ement. Having alluded to the subject of reversion, I may here refer to a statement ...
... crossed ofl'spring from a short-horned cow by a long-horned bull, the greater length of horn, though a peering late in life, is clearly due to the male ement. Having alluded to the subject of reversion, I may here refer to a statement ...
Página 15
... crossed ,-—-a subject ereafier to be discussed), domestic races of the same species difl'er from each other in the same manner as, only in most cases in a lesser degree than, do closely-allied species of the same genus in a state of ...
... crossed ,-—-a subject ereafier to be discussed), domestic races of the same species difl'er from each other in the same manner as, only in most cases in a lesser degree than, do closely-allied species of the same genus in a state of ...
Página 18
... crossing of a few aboriginal species; but by crossing we can only get forms in some degree intermediate between their parents ; and if we account for our several domestic races by this process, we must admit the former existence of the ...
... crossing of a few aboriginal species; but by crossing we can only get forms in some degree intermediate between their parents ; and if we account for our several domestic races by this process, we must admit the former existence of the ...
Página 19
... crossed one with another for several generations, hardly two of them will be alike, and then the extreme difliculty, or rather utter hopelessness, of the task becomes apparent. Certainly, a breed intermediate between two very distinct ...
... crossed one with another for several generations, hardly two of them will be alike, and then the extreme difliculty, or rather utter hopelessness, of the task becomes apparent. Certainly, a breed intermediate between two very distinct ...
Página 21
... rock-pigeon, they must have descended from at least seven or eight aboriginal stocks; for it is impossible to make the present domestic breeds by the crossing of any lesser number: how, for instance, could a VARIATION UNDER DOMESTICATION ...
... rock-pigeon, they must have descended from at least seven or eight aboriginal stocks; for it is impossible to make the present domestic breeds by the crossing of any lesser number: how, for instance, could a VARIATION UNDER DOMESTICATION ...
Contenido
5 | |
ON was GEOLOGICAL SUCCESSION OF ORGANIC | 155 |
GEOGRAPHICAL DISTRIBUTION | 282 |
Gnoonnmcu DISTRIBUTION Continued | 302 |
RECAPITULATION AND CONCLUSION | 415 |
41 | 449 |
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Términos y frases comunes
action adapted advantage allied America amount ancient animals appear become believe birds breeds cause characters climate closely common considered continuous crossed descendants difl'erent distinct domestic doubt evidence existing extinct extremely facts families favourable fertility find first flowers follow formations forms genera genus give given greater groups habits hand Hence hybrids important increase individuals inhabitants inherited insects instance instincts intermediate islands kind known land laws less lines living look males manner means migration modification namely natural selection naturalists nearly never observed occur organic origin parent perfect period plants points present principle probably produced range ranked reason regions remains remarked resemble seeds seems seen separated shown single slight sometimes species sterility structure struggle successive suppose tend theory tion trees variability variations varieties vary whole widely