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 8
... closely allied species , we Difficulty of generally perceive in each domestic race , as already remarked , less ... allied . With these exceptions ( and with that of the perfect fertility of varieties when crossed , —a subject hereafter ...
... closely allied species , we Difficulty of generally perceive in each domestic race , as already remarked , less ... allied . With these exceptions ( and with that of the perfect fertility of varieties when crossed , —a subject hereafter ...
Página 44
... closely allied forms , marked for me by Mr. Watson as doubtful species , but which are almost universally ranked by British botanists as good and true species . Finally , varieties cannot be distinguished from species , except , first ...
... closely allied forms , marked for me by Mr. Watson as doubtful species , but which are almost universally ranked by British botanists as good and true species . Finally , varieties cannot be distinguished from species , except , first ...
Página 369
... closely - allied species invading each other's territory , when put into free intercommunication . Undoubtedly , if one species has any advantage over another , it will in a very brief time wholly or in part supplant it ; but if both ...
... closely - allied species invading each other's territory , when put into free intercommunication . Undoubtedly , if one species has any advantage over another , it will in a very brief time wholly or in part supplant it ; but if both ...
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