On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeD. Appleton, 1909 - 430 páginas |
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Página 21
... remarked , have apparently been exposed to exactly the same conditions of life ; and this shows how unim- portant the direct effects of the conditions of life are in comparison with the laws of reproduction , of growth , and of ...
... remarked , have apparently been exposed to exactly the same conditions of life ; and this shows how unim- portant the direct effects of the conditions of life are in comparison with the laws of reproduction , of growth , and of ...
Página 26
... remarked , less uniformity of character than in true species . Domestic races of the same species , also , often have a somewhat monstrous character ; by which I mean , that , although differing from each other , and from other species ...
... remarked , less uniformity of character than in true species . Domestic races of the same species , also , often have a somewhat monstrous character ; by which I mean , that , although differing from each other , and from other species ...
Página 44
... remarked by some authors , namely , that the varieties kept by savages have more of the character of species than the varieties kept in civilised countries . ] [ On the view here given of the all - important part which selection by man ...
... remarked by some authors , namely , that the varieties kept by savages have more of the character of species than the varieties kept in civilised countries . ] [ On the view here given of the all - important part which selection by man ...
Página 46
... remarked , with respect to the sheep of parts of Yorkshire , that " as they generally belong to poor people , and are mostly in small lots , they never can be improved . " On the other hand , nurserymen , from raising large stocks of ...
... remarked , with respect to the sheep of parts of Yorkshire , that " as they generally belong to poor people , and are mostly in small lots , they never can be improved . " On the other hand , nurserymen , from raising large stocks of ...
Página 60
... remarked in regard to plants , and Westwood in regard to insects , that in large genera the amount of difference between the species is often exceedingly small . I have endeavoured to test this numerically by averages , and , as far as ...
... remarked in regard to plants , and Westwood in regard to insects , that in large genera the amount of difference between the species is often exceedingly small . I have endeavoured to test this numerically by averages , and , as far as ...
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Términos y frases comunes
accumulated adapted affinities allied species America analogous ancient animals appear archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour continuous crossed crustaceans degree difficulty distinct species divergence domestic doubt embryo endemic existing exterminated extinct extremely facts favourable fertilised fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids hybrids produced important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate larvæ laws less living males mammals manner migration modification modified descendants natural selection naturalists nearly nest occasionally offspring organic organisation origin of species perfect pigeons plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary seeds sexual sexual selection Silurian slight sometimes South America sterility structure struggle successive supposed swimbladder tend theory variability variations varieties vary whole widely