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 5
... difficulties in accepting the theory will be given : namely , first , the difficulties of transitions , or how a simple being or a simple organ can be changed and per- fected into a highly developed being or into an elab- orately ...
... difficulties in accepting the theory will be given : namely , first , the difficulties of transitions , or how a simple being or a simple organ can be changed and per- fected into a highly developed being or into an elab- orately ...
Página 7
... Difficulty of distinguishing between Varieties and Species - Origin of Domestic Varieties from one or more Species - Domestic Pigeons , their Differences and Origin- Principles of Selection , anciently followed , their Effects ...
... Difficulty of distinguishing between Varieties and Species - Origin of Domestic Varieties from one or more Species - Domestic Pigeons , their Differences and Origin- Principles of Selection , anciently followed , their Effects ...
Página 16
... difficulty in proving its truth : we may safely conclude that very many of the most strongly marked domestic varieties could not possibly live in a wild . state . In many cases we do not know what 16 VARIATION UNDER DOMESTICATION ...
... difficulty in proving its truth : we may safely conclude that very many of the most strongly marked domestic varieties could not possibly live in a wild . state . In many cases we do not know what 16 VARIATION UNDER DOMESTICATION ...
Página 17
... , and esculent vegetables , for an unlimited number of generations , would be opposed to all experience . Character of Domestic Varieties ; difficulty of dis- tinguishing between CHAP . I. ] VARIATION UNDER DOMESTICATION . 17.
... , and esculent vegetables , for an unlimited number of generations , would be opposed to all experience . Character of Domestic Varieties ; difficulty of dis- tinguishing between CHAP . I. ] VARIATION UNDER DOMESTICATION . 17.
Página 18
... difficulty of dis- tinguishing between Varieties and Species ; origin of Domestic Varieties from one or more Species . When we look to the hereditary varieties or races of our domestic animals and plants , and compare them with closely ...
... difficulty of dis- tinguishing between Varieties and Species ; origin of Domestic Varieties from one or more Species . When we look to the hereditary varieties or races of our domestic animals and plants , and compare them with closely ...
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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