On the Origin of Species by Means of Natural Selection: Or The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1888 - 458 páginas |
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Página 6
... extremely difficult to come to any conclusion in regard to the extent of the changes which have been thus definitely induced . There can , however , be little doubt about many slight changes , such as size from the amount of food ...
... extremely difficult to come to any conclusion in regard to the extent of the changes which have been thus definitely induced . There can , however , be little doubt about many slight changes , such as size from the amount of food ...
Página 7
... extremely sensitive to any change in the con- ditions , and partly from the similarity , as Köireuter and others have remarked , between the variability which follows from the crossing of distinct species , and that which may be ...
... extremely sensitive to any change in the con- ditions , and partly from the similarity , as Köireuter and others have remarked , between the variability which follows from the crossing of distinct species , and that which may be ...
Página 24
... extremely alike the flowers ; how unlike the flowers of the heartsease are , and how alike the leaves ; how much the fruit of the different kinds of gooseberries differ in size , colour , shape , and hairiness , and yet the flowers ...
... extremely alike the flowers ; how unlike the flowers of the heartsease are , and how alike the leaves ; how much the fruit of the different kinds of gooseberries differ in size , colour , shape , and hairiness , and yet the flowers ...
Página 35
... extremely perplexing : I refer to those genera which have been called " protean " or " polymorphic , " in which the species present an inor- dinate amount of variation . With respect to many of these forms , hardly two naturalists agree ...
... extremely perplexing : I refer to those genera which have been called " protean " or " polymorphic , " in which the species present an inor- dinate amount of variation . With respect to many of these forms , hardly two naturalists agree ...
Página 52
... extremely few , is , that the slow - breeders would require a few more years to people , under favourable conditions , a whole district , let it be ever so large . The condor lays a couple of eggs and the ostrich a score , and yet in ...
... extremely few , is , that the slow - breeders would require a few more years to people , under favourable conditions , a whole district , let it be ever so large . The condor lays a couple of eggs and the ostrich a score , and yet in ...
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Términos y frases comunes
adapted admit affinities allied species America analogous ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked reproductive resemblance rudimentary seeds sexual selection slight South America stamens sterility structure struggle successive supposed tend theory tion variability variations varieties vary whilst whole wings young