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 xx
... separated from the extinct by new creations , but are tc be regarded as their descendants through continued reproduction . " A well - known French botanist , M. Lecoq , writes in 1854 ( ' Etudes sur Géograph . Bot . , ' tom . i . p ...
... separated from the extinct by new creations , but are tc be regarded as their descendants through continued reproduction . " A well - known French botanist , M. Lecoq , writes in 1854 ( ' Etudes sur Géograph . Bot . , ' tom . i . p ...
Página 6
... separated by any distinct line from slighter variations . All such changes of structure , whether extremely slight or strongly marked , which appear amongst many individuals living together , may be considered as the indefinite effects ...
... separated by any distinct line from slighter variations . All such changes of structure , whether extremely slight or strongly marked , which appear amongst many individuals living together , may be considered as the indefinite effects ...
Página 37
... separated areas . How many of the birds and insects in North America and Europe , which differ very slightly from each other , have been ranked by one eminent naturalist as undoubted species , and by another as varieties , or , as they ...
... separated areas . How many of the birds and insects in North America and Europe , which differ very slightly from each other , have been ranked by one eminent naturalist as undoubted species , and by another as varieties , or , as they ...
Página 74
... separation of the sexes might be effected . It would take up too much space to show the various steps , through dimorphism and other means , by which the separation of the sexes in plants of various kinds is apparently now in progress ...
... separation of the sexes might be effected . It would take up too much space to show the various steps , through dimorphism and other means , by which the separation of the sexes in plants of various kinds is apparently now in progress ...
Página 76
... separated sexes , it is of course obvious that two individuals must always ( with the exception of the curious and not well - understood cases of parthenogenesis ) unite for each birth , but in the case of hermaphrodites this is far ...
... separated sexes , it is of course obvious that two individuals must always ( with the exception of the curious and not well - understood cases of parthenogenesis ) unite for each birth , but in the case of hermaphrodites this is far ...
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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