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 34
... rank one form as a variety of another , even when they are closely connected by intermediate links ; nor will the ... ranked as a variety of another , not because the intermediate links have actually been found , but because analogy ...
... rank one form as a variety of another , even when they are closely connected by intermediate links ; nor will the ... ranked as a variety of another , not because the intermediate links have actually been found , but because analogy ...
Página 35
... ranked by naturalists as true species . Nevertheless , no certain criterion can possibly be given by which variable ... rank them as distinct species ; but what distance , it has been well asked , will suffice ; if that between America ...
... ranked by naturalists as true species . Nevertheless , no certain criterion can possibly be given by which variable ... rank them as distinct species ; but what distance , it has been well asked , will suffice ; if that between America ...
Página 36
... rank of varieties . Some few naturalists maintain that animals never present varieties ; but then these same naturalists rank the slightest difference as of specific value ; and when the same identical form is met with in two distant ...
... rank of varieties . Some few naturalists maintain that animals never present varieties ; but then these same naturalists rank the slightest difference as of specific value ; and when the same identical form is met with in two distant ...
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