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 18
... forms in some degree intermediate between their parents ; and if we account for our several domestic races by this process , we must admit the former existence of the most extreme forms , as the Italian greyhound , bloodhound , bull ...
... forms in some degree intermediate between their parents ; and if we account for our several domestic races by this process , we must admit the former existence of the most extreme forms , as the Italian greyhound , bloodhound , bull ...
Página 43
... forms to rank as species and which as varieties . We may instance Rubus , Rosa , and Hieracium amongst plants ... forms which possess in some considerable degree the character of species , but which are so closely similar to some other ...
... forms to rank as species and which as varieties . We may instance Rubus , Rosa , and Hieracium amongst plants ... forms which possess in some considerable degree the character of species , but which are so closely similar to some other ...
Página 44
... forms have permanently retained their characters in their own country for a long time ; for as long , as far as we know , as have good and true species . Practically , when a naturalist can unite two forms together by others having ...
... forms have permanently retained their characters in their own country for a long time ; for as long , as far as we know , as have good and true species . Practically , when a naturalist can unite two forms together by others having ...
Página 45
... forms ! Amongst animals which unite for each birth , and which are highly locomotive , doubtful forms , ranked by one zoologist as a species and by another as a variety , can rarely be found within the same country , but are common in ...
... forms ! Amongst animals which unite for each birth , and which are highly locomotive , doubtful forms , ranked by one zoologist as a species and by another as a variety , can rarely be found within the same country , but are common in ...
Página 46
... forms . Yet it must be confessed that it is in the best - known countries that we find the greatest number of forms of doubtful value . I have been struck with the fact , that if any animal or plant in a state of nature be highly useful ...
... forms . Yet it must be confessed that it is in the best - known countries that we find the greatest number of forms of doubtful value . I have been struck with the fact , that if any animal or plant in a state of nature be highly useful ...
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