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 6
... genera are lineal descendants of some other and generally extinct species , in the same manner as the acknowledged varieties of any one species are the descendants of that species . Furthermore , I am convinced that Natural Selection ...
... genera are lineal descendants of some other and generally extinct species , in the same manner as the acknowledged varieties of any one species are the descendants of that species . Furthermore , I am convinced that Natural Selection ...
Página 15
... genera which I shall presently give , we have no right to expect often to meet with generic differences in our domesticated productions . It has often been differ from each I think it could When we attempt to estimate the amount of ...
... genera which I shall presently give , we have no right to expect often to meet with generic differences in our domesticated productions . It has often been differ from each I think it could When we attempt to estimate the amount of ...
Página 24
... genera- tions . In a breed which has been crossed only once with some distinct breed , the tendency to reversion to any character derived from such cross will naturally become less and less , as in each succeeding genera- tion there ...
... genera- tions . In a breed which has been crossed only once with some distinct breed , the tendency to reversion to any character derived from such cross will naturally become less and less , as in each succeeding genera- tion there ...
Página 41
... genera - Many of the species of the larger genera resemble varieties in being very closely , but unequally , related to each other , and in having restricted ranges . BEFORE applying the principles arrived at in the last chapter to ...
... genera - Many of the species of the larger genera resemble varieties in being very closely , but unequally , related to each other , and in having restricted ranges . BEFORE applying the principles arrived at in the last chapter to ...
Página 43
... genera of insects , and several genera of Brachiopod shells . In most polymorphic genera some of the species have fixed and definite characters . Genera which are polymorphic in one country seem to be , with some few exceptions ...
... genera of insects , and several genera of Brachiopod shells . In most polymorphic genera some of the species have fixed and definite characters . Genera which are polymorphic in one country seem to be , with some few exceptions ...
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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