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 20
... given . The explanation , I think , is simple : from long - continued study they are strongly impressed with the differences between the several races ; and though they well know that each race varies slightly , for they win their ...
... given . The explanation , I think , is simple : from long - continued study they are strongly impressed with the differences between the several races ; and though they well know that each race varies slightly , for they win their ...
Página 21
... given it existence . " In Saxony the importance of the principle of selection in regard to merino sheep is so fully recog- nised , that men follow it as a trade : the sheep are placed on a table and are studied , like a picture by a ...
... given it existence . " In Saxony the importance of the principle of selection in regard to merino sheep is so fully recog- nised , that men follow it as a trade : the sheep are placed on a table and are studied , like a picture by a ...
Página 22
... given for animals with a good pedigree ; and these have been exported to almost every quarter of the world . The im- provement is by no means generally due to crossing different breeds ; all the best breeders are strongly opposed to ...
... given for animals with a good pedigree ; and these have been exported to almost every quarter of the world . The im- provement is by no means generally due to crossing different breeds ; all the best breeders are strongly opposed to ...
Página 23
... given in an ancient Chinese encyclopædia . Explicit rules are laid down by some of the Roman classical writers . From passages in Genesis , it is clear that the colour of domesticated animals was at that early period attended to ...
... given in an ancient Chinese encyclopædia . Explicit rules are laid down by some of the Roman classical writers . From passages in Genesis , it is clear that the colour of domesticated animals was at that early period attended to ...
Página 26
... given of the important part which selection by man has played , it becomes at once obvious , how it is that our domestic races show adaptation in their structure or in their habits to man's wants or fancies . We can , I think , further ...
... given of the important part which selection by man has played , it becomes at once obvious , how it is that our domestic races show adaptation in their structure or in their habits to man's wants or fancies . We can , I think , further ...
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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