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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... DIFFICULTIES ON THEORY 154 7. INSTINCT 186 8. HYBRIDISM 220 9. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD 250 10. ON THE GEOLOGICAL SUCCESSION OF ORGANIC BEINGS 280 11. GEOGRAPHICAL DISTRIBUTION 12. GEOGRAPHICAL DISTRIBUTION ...
... DIFFICULTIES ON THEORY 154 7. INSTINCT 186 8. HYBRIDISM 220 9. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD 250 10. ON THE GEOLOGICAL SUCCESSION OF ORGANIC BEINGS 280 11. GEOGRAPHICAL DISTRIBUTION 12. GEOGRAPHICAL DISTRIBUTION ...
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... difficulties on the theory will be given namely , first , the difficulties of transi- tions , or in understanding how a simple being or a simple organ can be changed and perfected into a highly developed being or elaborately constructed ...
... difficulties on the theory will be given namely , first , the difficulties of transi- tions , or in understanding how a simple being or a simple organ can be changed and perfected into a highly developed being or elaborately constructed ...
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... Difficulty of dis tinguishing between Varieties and Species - Origin of Domestic Varieties from one or more Species - Domestic Pigeons , their Differences and Origin - Principle of Selection anciently followed , its Effects - Methodical ...
... Difficulty of dis tinguishing between Varieties and Species - Origin of Domestic Varieties from one or more Species - Domestic Pigeons , their Differences and Origin - Principle of Selection anciently followed , its Effects - Methodical ...
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... on what decisive facts the above statement has so often and so boldly been made . There would be great difficulty in proving its truth : we may safely conclude that very many of the most strongly - marked VARIATION UNDER DOMESTICATION 13.
... on what decisive facts the above statement has so often and so boldly been made . There would be great difficulty in proving its truth : we may safely conclude that very many of the most strongly - marked VARIATION UNDER DOMESTICATION 13.
Página 19
... difficulty , or rather utter hopelessness , of the task becomes apparent . Certainly , a breed intermediate between two very distinct breeds could not be got without extreme care and long - continued selection ; nor can I find a single ...
... difficulty , or rather utter hopelessness , of the task becomes apparent . Certainly , a breed intermediate between two very distinct breeds could not be got without extreme care and long - continued selection ; nor can I find a single ...
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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