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 81
... less modification and less extermination . Hence , we can understand how it is that the flora of Madeira , according to Oswald Heer , resembles to a certain extent the extinct tertiary flora of Europe . All fresh - water basins , taken ...
... less modification and less extermination . Hence , we can understand how it is that the flora of Madeira , according to Oswald Heer , resembles to a certain extent the extinct tertiary flora of Europe . All fresh - water basins , taken ...
Página 300
... less degree , thus causing a greater or less amount of permanent modification , will depend on many complex contingencies - on the variations being of a beneficial nature , on the freedom of intercrossing , on the slowly changing ...
... less degree , thus causing a greater or less amount of permanent modification , will depend on many complex contingencies - on the variations being of a beneficial nature , on the freedom of intercrossing , on the slowly changing ...
Página 385
... less variable than the shape or colour of the body , & c .; whereas with sheep the horns are much less serviceable , because less constant . In classing varieties , I apprehend that if we had a real pedigree , a genealogical ...
... less variable than the shape or colour of the body , & c .; whereas with sheep the horns are much less serviceable , because less constant . In classing varieties , I apprehend that if we had a real pedigree , a genealogical ...
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