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 119
... developed in an unusual manner are highly variable : specific characters more variable than generic : secondary sexual characters variable - Species of the same genus vary in an analogous manner - Reversions to long - lost characters ...
... developed in an unusual manner are highly variable : specific characters more variable than generic : secondary sexual characters variable - Species of the same genus vary in an analogous manner - Reversions to long - lost characters ...
Página 122
... developed and appreciable by us . Effects of Use and Disuse . - From the facts alluded to in the first chapter , I think there can be little doubt that use in our domestic animals strengthens and en- larges certain parts , and disuse ...
... developed and appreciable by us . Effects of Use and Disuse . - From the facts alluded to in the first chapter , I think there can be little doubt that use in our domestic animals strengthens and en- larges certain parts , and disuse ...
Página 133
... any instances , for I see hardly any way of distinguishing between the effects , on the one hand , of a part being largely developed through natural selection and another and adjoining part being reduced by LAWS OF VARIATION 133.
... any instances , for I see hardly any way of distinguishing between the effects , on the one hand , of a part being largely developed through natural selection and another and adjoining part being reduced by LAWS OF VARIATION 133.
Página 134
... developed , and furnished with great nerves and muscles ; but in the parasitic and protected Proteolepas , the whole anterior part of the head is reduced to the merest rudiment attached to the basis of the prehensile antennæ . Now the ...
... developed , and furnished with great nerves and muscles ; but in the parasitic and protected Proteolepas , the whole anterior part of the head is reduced to the merest rudiment attached to the basis of the prehensile antennæ . Now the ...
Página 135
... developed in a corresponding degree . And , conversely , that natural selection may perfectly well succeed in largely developing any organ , without requiring as a necessary compensation the reduction of some adjoining part . It seems ...
... developed in a corresponding degree . And , conversely , that natural selection may perfectly well succeed in largely developing any organ , without requiring as a necessary compensation the reduction of some adjoining part . It seems ...
Otras ediciones - Ver todas
On the Origin of Species by Means of Natural Selection: or the Preservation ... Charles Darwin Vista previa limitada - 2023 |
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