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 vii
... crossing - Dimorphism and Trimorphism — Fertility of varieties when crossed and of their mongrel offspring not universal — Hybrids and mongrels compared independently of their tertility Summary - - 234-263 CHAPTER X. ON THE IMPERFECTION ...
... crossing - Dimorphism and Trimorphism — Fertility of varieties when crossed and of their mongrel offspring not universal — Hybrids and mongrels compared independently of their tertility Summary - - 234-263 CHAPTER X. ON THE IMPERFECTION ...
Página xiv
... crossing of already existing forms , and much to use and disuse , that is , to the effects of habit . To this latter agency he seems to attribute all the beautiful adaptations in nature ; —such as the long neck of the giraffe for ...
... crossing of already existing forms , and much to use and disuse , that is , to the effects of habit . To this latter agency he seems to attribute all the beautiful adaptations in nature ; —such as the long neck of the giraffe for ...
Página xvi
... crossing . Rafinesque , in his New Flora of North America , ' published in 1836 , wrote ( p . 6 ) as follows : - " All species might have been varieties once , and many varieties are gradually becoming species by assuming constant and ...
... crossing . Rafinesque , in his New Flora of North America , ' published in 1836 , wrote ( p . 6 ) as follows : - " All species might have been varieties once , and many varieties are gradually becoming species by assuming constant and ...
Página 7
... crossing of distinct species , and that which may be observed with plants and animals when reared under new or unnatural conditions Many facts clearly show how eminently susceptible the reproduc tive system is to very slight changes in ...
... crossing of distinct species , and that which may be observed with plants and animals when reared under new or unnatural conditions Many facts clearly show how eminently susceptible the reproduc tive system is to very slight changes in ...
Página 12
... crossed , —a subject hereafter to be discussed ) , domestic races of the same species differ from each other in the same manner as do the closely - allied species of the same genus in a state of nature , but the differences in most ...
... crossed , —a subject hereafter to be discussed ) , domestic races of the same species differ from each other in the same manner as do the closely - allied species of the same genus in a state of nature , but the differences in most ...
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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