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 27
... above - specified breeds , though agreeing generally with the wild rock - pigeon in constitution , habits , voice , colouring , and in most parts of their structure , yet are certainly highly abnor CHAP . I. ] 27 DOMESTIC PIGEONS .
... above - specified breeds , though agreeing generally with the wild rock - pigeon in constitution , habits , voice , colouring , and in most parts of their structure , yet are certainly highly abnor CHAP . I. ] 27 DOMESTIC PIGEONS .
Página 43
... structure , would often succeed better in the one country than in the other ; and thus by a process of " natural selection , " as will hereafter be more fully explained , two sub - breeds might be formed . This , perhaps , partly ...
... structure , would often succeed better in the one country than in the other ; and thus by a process of " natural selection , " as will hereafter be more fully explained , two sub - breeds might be formed . This , perhaps , partly ...
Página 44
... structure excepting such as is externally visible ; and indeed he rarely cares for what is internal . He can never act by selection , excepting on variations which are first given to him in some slight degree by nature . No man would ...
... structure excepting such as is externally visible ; and indeed he rarely cares for what is internal . He can never act by selection , excepting on variations which are first given to him in some slight degree by nature . No man would ...
Página 52
... structure such as we occasionally see in our domestic productions , more especially with plants , are ever ... structures in widely different animals . Thus pigs have occasionally been born with a sort of proboscis , and if any wild ...
... structure such as we occasionally see in our domestic productions , more especially with plants , are ever ... structures in widely different animals . Thus pigs have occasionally been born with a sort of proboscis , and if any wild ...
Página 94
... structure of every organic being is related , in the most essential yet often hidden manner , to that of all the other organic beings , with which it comes into compe- tition for food or residence , or from which it has to escape , or ...
... structure of every organic being is related , in the most essential yet often hidden manner , to that of all the other organic beings , with which it comes into compe- tition for food or residence , or from which it has to escape , or ...
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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