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 15
... naturalists differ widely in determining what characters are of generic value ; all such valuations being at present empirical . Moreover , on the view of the origin of genera which I shall presently give , we have no right to expect ...
... naturalists differ widely in determining what characters are of generic value ; all such valuations being at present empirical . Moreover , on the view of the origin of genera which I shall presently give , we have no right to expect ...
Página 21
... naturalists is correct , namely , that all have de- scended from the rock - pigeon ( Columba livia ) , including under this term several geographical races or sub- species , which differ from each other in the most trifling respects ...
... naturalists is correct , namely , that all have de- scended from the rock - pigeon ( Columba livia ) , including under this term several geographical races or sub- species , which differ from each other in the most trifling respects ...
Página 41
... naturalists ; yet every naturalist knows vaguely what he means when he speaks of a species . Generally the term includes the unknown element of a distinct act of creation . The term ' variety ' is almost equally difficult to define ...
... naturalists ; yet every naturalist knows vaguely what he means when he speaks of a species . Generally the term includes the unknown element of a distinct act of creation . The term ' variety ' is almost equally difficult to define ...
Página 42
... naturalists consider unimportant parts ; but I could show by a long catalogue of facts , that parts which must be ... naturalist would be surprised at the number of the cases of variability , even in important parts of structure , which ...
... naturalists consider unimportant parts ; but I could show by a long catalogue of facts , that parts which must be ... naturalist would be surprised at the number of the cases of variability , even in important parts of structure , which ...
Página 43
... naturalists have honestly confessed ) which does not vary ; and , under this point of view , no instance of an important part varying will ever be found : but under any other point of view many instances assuredly can be given . There ...
... naturalists have honestly confessed ) which does not vary ; and , under this point of view , no instance of an important part varying will ever be found : but under any other point of view many instances assuredly can be given . There ...
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