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 24
... less and less , as in each succeeding genera- tion there will be less of the foreign blood ; but when there has been no cross with a distinct breed , and there is a tendency in both parents to revert to a char- acter , which has been ...
... less and less , as in each succeeding genera- tion there will be less of the foreign blood ; but when there has been no cross with a distinct breed , and there is a tendency in both parents to revert to a char- acter , which has been ...
Página 27
... less of the laws of inheritance than does the breeder , and knowing no more than he does of the intermediate links in the long lines of descent , yet admit that many of our domestic races have descended from the same parents - may they ...
... less of the laws of inheritance than does the breeder , and knowing no more than he does of the intermediate links in the long lines of descent , yet admit that many of our domestic races have descended from the same parents - may they ...
Página 32
... less civilised dis- tricts , where the breed has been less improved . There is reason to believe that King Charles's spaniel has been unconsciously modified to a large extent since the time of that monarch . Some highly competent ...
... less civilised dis- tricts , where the breed has been less improved . There is reason to believe that King Charles's spaniel has been unconsciously modified to a large extent since the time of that monarch . Some highly competent ...
Página 39
... less than others , yet the rarity or absence of distinct breeds of the cat , the donkey , peacock , goose , etc. , may be attributed in main part to selection not having been brought into play : in cats , from the diffi- culty in ...
... less than others , yet the rarity or absence of distinct breeds of the cat , the donkey , peacock , goose , etc. , may be attributed in main part to selection not having been brought into play : in cats , from the diffi- culty in ...
Página 49
... less distinct and more fluctuating forms . The term variety , again , in comparison with mere individual differences , is also applied arbitrarily , and for mere convenience ' sake . I Guided by theoretical considerations , I thought ...
... less distinct and more fluctuating forms . The term variety , again , in comparison with mere individual differences , is also applied arbitrarily , and for mere convenience ' sake . I Guided by theoretical considerations , I thought ...
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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