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 16
... kind so truly , were the offspring of any single species , then such facts would have great weight in making us doubt about the immutability of the many very closely - allied natural species - for instance , of the many foxes ...
... kind so truly , were the offspring of any single species , then such facts would have great weight in making us doubt about the immutability of the many very closely - allied natural species - for instance , of the many foxes ...
Página 30
... kind of selection is , in fact , also followed ; for hardly any one is so careless as to allow his worst animals to breed . In regard to plants , there is another means of ob- serving the accumulated effects of selection - namely , by ...
... kind of selection is , in fact , also followed ; for hardly any one is so careless as to allow his worst animals to breed . In regard to plants , there is another means of ob- serving the accumulated effects of selection - namely , by ...
Página 32
... kind of Selection , which may be called Unconscious , and which results from every one trying to possess and breed from the best individual animals , is more im- portant . Thus , a man who intends keeping pointers naturally tries to get ...
... kind of Selection , which may be called Unconscious , and which results from every one trying to possess and breed from the best individual animals , is more im- portant . Thus , a man who intends keeping pointers naturally tries to get ...
Página 33
... kind of unconscious selection going on . We see the value set on animals even by the barbarians of Tierra del Fuego , by their killing and devouring their D old women , in times of dearth , as or VARIATION UNDER DOMESTICATION 33.
... kind of unconscious selection going on . We see the value set on animals even by the barbarians of Tierra del Fuego , by their killing and devouring their D old women , in times of dearth , as or VARIATION UNDER DOMESTICATION 33.
Página 43
... kind of varia- bility is independent of the conditions of life . I am inclined to suspect that we see in these polymorphic genera variations in points of structure which are of no service or disservice to the species , and which con ...
... kind of varia- bility is independent of the conditions of life . I am inclined to suspect that we see in these polymorphic genera variations in points of structure which are of no service or disservice to the species , and which con ...
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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