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 33
... forms , not connected by intermediate varieties . Fritz Müller has described analogous but more extraordinary cases with the males of certain Brazilian Crustaceans : thus , the male of the Tanais regularly occurs under two distinct forms ...
... forms , not connected by intermediate varieties . Fritz Müller has described analogous but more extraordinary cases with the males of certain Brazilian Crustaceans : thus , the male of the Tanais regularly occurs under two distinct forms ...
Página 34
... form as a variety of another , even when they are closely connected by intermediate links ; nor will the commonly- assumed hybrid nature of the intermediate forms always remove the difficulty . In very many cases , however , one form is ...
... form as a variety of another , even when they are closely connected by intermediate links ; nor will the commonly- assumed hybrid nature of the intermediate forms always remove the difficulty . In very many cases , however , one form is ...
Página 433
... forms , with the slow modification of their descendants , causes the forms of life , after long intervals of time , to appear as if they had changed simultaneously throughout the world . The fact of the fossil remains of each formation ...
... forms , with the slow modification of their descendants , causes the forms of life , after long intervals of time , to appear as if they had changed simultaneously throughout the world . The fact of the fossil remains of each formation ...
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