The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página 3
... 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 perfected into a highly developed being or into an elaborately con ...
... 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 perfected into a highly developed being or into an elaborately con ...
Página 5
... 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 10
... 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 the aboriginal stock was , and so could ...
... 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 the aboriginal stock was , and so could ...
Página 11
... difficulty of distinguishing 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 distinguishing 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 ...
Página 14
... difficulty of the task becomes manifest . Breeds of the Domestic Pigeon , their Differences and Origin . Believing that it is always best to study some special group , I have , after deliberation , taken up domestic pigeons . I have ...
... difficulty of the task becomes manifest . Breeds of the Domestic Pigeon , their Differences and Origin . Believing that it is always best to study some special group , I have , after deliberation , taken up domestic pigeons . I have ...
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important increase 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 resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young