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
... seeds that must be transported by certain birds , and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen from one flower to the other , it is equally preposterous to account for the ...
... seeds that must be transported by certain birds , and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen from one flower to the other , it is equally preposterous to account for the ...
Página 8
... seed ! In some few such cases it has been discovered that very trifling changes , such as a little more or less water at some particular period of growth , will determine whether or not the plant sets a seed . I cannot here enter on the ...
... seed ! In some few such cases it has been discovered that very trifling changes , such as a little more or less water at some particular period of growth , will determine whether or not the plant sets a seed . I cannot here enter on the ...
Página 9
... seed . These ' sports ' are extremely rare under nature , but far from rare under cultivation ; and in this case we see that the treatment of the parent has affected a bud or offset , and not the ovules or pollen . But it is the opinion ...
... seed . These ' sports ' are extremely rare under nature , but far from rare under cultivation ; and in this case we see that the treatment of the parent has affected a bud or offset , and not the ovules or pollen . But it is the opinion ...
Página 27
... seeds of the same tree . Innumerable other examples could be given . The explanation , I think , is simple : from long- continued study they are strongly impressed with the differences between the several races ; and though they well ...
... seeds of the same tree . Innumerable other examples could be given . The explanation , I think , is simple : from long- continued study they are strongly impressed with the differences between the several races ; and though they well ...
Página 30
... seed - raisers do not pick out the best plants , but merely go over their seed - beds , and pull up the ' rogues , ' as they call the plants that deviate from the proper standard . With animals this kind of selection is , in fact , also ...
... seed - raisers do not pick out the best plants , but merely go over their seed - beds , and pull up the ' rogues , ' as they call the plants that deviate from the proper standard . With animals this kind of selection is , in fact , also ...
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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