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 38
... group of organisms quite unknown to him , he is at first much perplexed in determining what differences to consider as ... groups and in other countries , by which to correct his first impressions . As he extends the range of his ...
... group of organisms quite unknown to him , he is at first much perplexed in determining what differences to consider as ... groups and in other countries , by which to correct his first impressions . As he extends the range of his ...
Página 43
... groups . As Fries has well remarked , little groups of species are generally clustered like satellites around other species . And what are varieties but groups of forms , unequally related to each other , and clustered round certain ...
... groups . As Fries has well remarked , little groups of species are generally clustered like satellites around other species . And what are varieties but groups of forms , unequally related to each other , and clustered round certain ...
Página 44
... groups subordinate to groups . CHAPTER III . STRUGGLE FOR EXISTENCE . Its bearing on natural selection - The term used in a wide sense - Geometrical ratio of increase - Rapid increase of naturalised animals and plants- Nature of the ...
... groups subordinate to groups . CHAPTER III . STRUGGLE FOR EXISTENCE . Its bearing on natural selection - The term used in a wide sense - Geometrical ratio of increase - Rapid increase of naturalised animals and plants- Nature of the ...
Página 45
... groups of species , which constitute what are called distinct genera , and which differ from each other more than do the species of the same genus , arise ? All these results , as we shall more fully see in the next chapter , follow ...
... groups of species , which constitute what are called distinct genera , and which differ from each other more than do the species of the same genus , arise ? All these results , as we shall more fully see in the next chapter , follow ...
Página 71
... groups of animals , pair for each birth . Modern research has much diminished the number of supposed hermaphrodites , and of real hermaphrodites a large number pair ; that is , two individuals regularly unite for reproduction , which is ...
... groups of animals , pair for each birth . Modern research has much diminished the number of supposed hermaphrodites , and of real hermaphrodites a large number pair ; that is , two individuals regularly unite for reproduction , which is ...
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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