The Origin of Species by Means of Natural Selection: Or, the Preservation of Favored Races in the Struggle for Life, Volumen1D. Appleton, 1898 |
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Página 40
... increased in weight and in early maturity , compared with the stock formerly kept in this country . By comparing the ac- counts given in various old treatises of the former and present state of carrier and tumbler pigeons in Britain ...
... increased in weight and in early maturity , compared with the stock formerly kept in this country . By comparing the ac- counts given in various old treatises of the former and present state of carrier and tumbler pigeons in Britain ...
Página 42
... increased size and beauty which we now see in the varieties of the heartsease , rose , pelargonium , dahlia , and other plants , when compared with the older varieties or with their parent - stocks . No one would ever expect to get a ...
... increased size and beauty which we now see in the varieties of the heartsease , rose , pelargonium , dahlia , and other plants , when compared with the older varieties or with their parent - stocks . No one would ever expect to get a ...
Página 46
... increased by a large number of individuals being kept . Hence , number is of the highest importance for success . On this principle Marshall formerly remarked , with respect to the sheep of parts of Yorkshire , " as they generally ...
... increased by a large number of individuals being kept . Hence , number is of the highest importance for success . On this principle Marshall formerly remarked , with respect to the sheep of parts of Yorkshire , " as they generally ...
Página 48
... increased to their utmost limit , could not , after remaining fixed for many centuries , again vary under new conditions of life . No doubt , as Mr. Wallace has remarked with much truth , a limit will be at last reached . For in- stance ...
... increased to their utmost limit , could not , after remaining fixed for many centuries , again vary under new conditions of life . No doubt , as Mr. Wallace has remarked with much truth , a limit will be at last reached . For in- stance ...
Página 49
... we do not know , may be attributed to the definite action of the conditions of life . Some , perhaps a great , effect may be attributed The final re- to the increased use or disuse of. CHAP . I. ] 49 CIRCUMSTANCES FAVOURABLE .
... we do not know , may be attributed to the definite action of the conditions of life . Some , perhaps a great , effect may be attributed The final re- to the increased use or disuse of. CHAP . I. ] 49 CIRCUMSTANCES FAVOURABLE .
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Términos y frases comunes
adapted advantage allied analogous animals and plants appear Asa Gray beak become bees believe birds breeds caudicle cause cells characters climate closely colour common crossed cuckoo degree descendants developed difficulty distinct species disuse divergence domestic animals domestic races doubt effects eggs existence extinct extremely facts favourable females flowers forms Fritz Müller genera genus giraffe gradations greater number groups habits Hence hermaphrodites hive-bee important increase inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ large number larger genera larvæ less males manner Melipona Mivart modified natural selection naturalists nearly nest occasionally offspring organisation organs origin Origin of Species parent perfect period pigeons pollen pollen-grains present preserved prey principle probably produced progenitor quadrupeds rank rarely Red Grouse relation remarked resemble rock-pigeon seeds sexes sexual selection slight stamens striped structure struggle supposed swimbladder tend tendency tion tree variability variations varieties vary widely wings young