On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
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Página 3
... birds , and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen ... bird had given birth to a woodpecker , and some plant to the mistletoe , and that these had been produced perfect as ...
... birds , and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen ... bird had given birth to a woodpecker , and some plant to the mistletoe , and that these had been produced perfect as ...
Página 8
... I may just mention that carnivorous animals , even from the tropics , breed in this country pretty freely under confinement , with the exception of the plantigrades or bear family ; whereas carnivorous birds , 8 ON THE ORIGIN OF SPECIES.
... I may just mention that carnivorous animals , even from the tropics , breed in this country pretty freely under confinement , with the exception of the plantigrades or bear family ; whereas carnivorous birds , 8 ON THE ORIGIN OF SPECIES.
Página 9
... birds , with the rarest exceptions , hardly ever lay fertile eggs . Many exotic plants have pollen utterly worthless , in the same exact condition as in the most sterile hybrids . When , on the one hand , we see domesticated animals and ...
... birds , with the rarest exceptions , hardly ever lay fertile eggs . Many exotic plants have pollen utterly worthless , in the same exact condition as in the most sterile hybrids . When , on the one hand , we see domesticated animals and ...
Página 19
... bird , is also remarkable from the wonderful development of the carunculated skin about the head , and this is accompanied by greatly elongated eyelids , very large external orifices to the nostrils , and a wide gape of mouth . The ...
... bird , is also remarkable from the wonderful development of the carunculated skin about the head , and this is accompanied by greatly elongated eyelids , very large external orifices to the nostrils , and a wide gape of mouth . The ...
Página 20
... bird of great size , with long , massive beak and large feet ; some of the sub - breeds of runts have very long necks ... birds the head and tail touch ; the oil - gland is quite aborted . Several other less distinct breeds might be ...
... bird of great size , with long , massive beak and large feet ; some of the sub - breeds of runts have very long necks ... birds the head and tail touch ; the oil - gland is quite aborted . Several other less distinct breeds might be ...
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Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely