The Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeCollier Books, 1962 - 512 páginas |
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Página 62
... ranked as a variety of another , not because the intermediate links have actually been found , but because analogy leads the observer to suppose either that they do now somewhere exist , or may formerly have existed ; and here a wide ...
... ranked as a variety of another , not because the intermediate links have actually been found , but because analogy leads the observer to suppose either that they do now somewhere exist , or may formerly have existed ; and here a wide ...
Página 63
... ranked by botanists as species ; and in making this list he has omitted many trifling varieties , but which nevertheless have been ranked by some botanists as species , and he has entirely omitted several highly polymorphic genera ...
... ranked by botanists as species ; and in making this list he has omitted many trifling varieties , but which nevertheless have been ranked by some botanists as species , and he has entirely omitted several highly polymorphic genera ...
Página 64
... ranked as distinct species by many entomologists . Even Ire- land has a few animals , now generally regarded as varieties , but which have been ranked as species by some zoologists . Several experienced ornithologists consider our ...
... ranked as distinct species by many entomologists . Even Ire- land has a few animals , now generally regarded as varieties , but which have been ranked as species by some zoologists . Several experienced ornithologists consider our ...
Contenido
An Historical Sketch | 15 |
Introduction | 25 |
Variation Under Nature | 58 |
Derechos de autor | |
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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 common continent crossed crustaceans degree developed difficulty distinct species domestic doubt eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological 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 male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil pollen present principle probably produced progenitor 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