On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeEaston Press, 1976 - 470 páginas |
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Página 45
... called species or sub- species or varieties ; what rank , for instance , the two or three hundred doubtful forms of British plants are entitled to hold , if the existence of any well - marked varieties be admitted . But the mere ...
... called species or sub- species or varieties ; what rank , for instance , the two or three hundred doubtful forms of British plants are entitled to hold , if the existence of any well - marked varieties be admitted . But the mere ...
Página 442
... called the plan of creation . The rules for classifying will no doubt become simpler when we have a definite object ... called aberrant , and which may fancifully be called living fossils , will aid us in forming a picture of the ancient ...
... called the plan of creation . The rules for classifying will no doubt become simpler when we have a definite object ... called aberrant , and which may fancifully be called living fossils , will aid us in forming a picture of the ancient ...
Página 457
... called from the presence in most cases of a backbone composed of numerous joints or vertebra , which constitutes the centre of the skeleton and at the same time supports and protects the central parts of the nervous system . WHORLS ...
... called from the presence in most cases of a backbone composed of numerous joints or vertebra , which constitutes the centre of the skeleton and at the same time supports and protects the central parts of the nervous system . WHORLS ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
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Términos y frases comunes
accumulated adapted admit affinities allied species America ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number groups of species habits Hence hybrids hybrids produced 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 offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds slight South America stamens sterility structure struggle successive supposed swimbladder theory variability variations varieties vary whilst whole wings young