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 38
... observation , -perhaps never , the case . The law of correlated variation , the importance of which should never be overlooked , will ensure some differences ; but , as a general rule , it can- not be doubted that the continued ...
... observation , -perhaps never , the case . The law of correlated variation , the importance of which should never be overlooked , will ensure some differences ; but , as a general rule , it can- not be doubted that the continued ...
Página 53
... observed in the individuals of the same species inhabiting the same confined locality , may be called individual differences . No one supposes that all the individuals of the same species are cast in the same actual mould . These in ...
... observed in the individuals of the same species inhabiting the same confined locality , may be called individual differences . No one supposes that all the individuals of the same species are cast in the same actual mould . These in ...
Página 56
... observed , with some dimorphic plants . It certainly at first appears a highly remarkable fact that the same female butterfly should have the power of producing at the same time three distinct female forms and a male ; and that an ...
... observed , with some dimorphic plants . It certainly at first appears a highly remarkable fact that the same female butterfly should have the power of producing at the same time three distinct female forms and a male ; and that an ...
Página 60
... observed by Mr. Walsh to present in their larval or mature state , or in both states , slight , though constant differences in colour , size , or in the nature of their secretions . In some instances the males alone , in other instances ...
... observed by Mr. Walsh to present in their larval or mature state , or in both states , slight , though constant differences in colour , size , or in the nature of their secretions . In some instances the males alone , in other instances ...
Página 64
... observations , he will meet with more cases of difficulty ; for he will encounter a greater number of closely - 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 ...
... observations , he will meet with more cases of difficulty ; for he will encounter a greater number of closely - 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 ...
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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