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 4
... slight variations . I will then pass on to the variability of species in a state of nature ; but I shall , unfortunately , be compelled to treat this subject far too briefly , as it can be treated properly only by giving long catalogues ...
... slight variations . I will then pass on to the variability of species in a state of nature ; but I shall , unfortunately , be compelled to treat this subject far too briefly , as it can be treated properly only by giving long catalogues ...
Página 10
... slight amount of change may , I think , be attributed to the direct action of the conditions of life - as , in some cases , increased size from amount of food , colour from par- ticular kinds of food or from light , and perhaps the ...
... slight amount of change may , I think , be attributed to the direct action of the conditions of life - as , in some cases , increased size from amount of food , colour from par- ticular kinds of food or from light , and perhaps the ...
Página 12
... slight and those of considerable physiological importance , is endless . Dr. Prosper Lucas's treatise , in two large volumes , is the fullest and the best on this subject . No breeder doubts how strong is the tendency to inheritance ...
... slight and those of considerable physiological importance , is endless . Dr. Prosper Lucas's treatise , in two large volumes , is the fullest and the best on this subject . No breeder doubts how strong is the tendency to inheritance ...
Página 14
... slight devia- tions in their structure , in such case , I grant that we could deduce nothing from domestic varieties in regard to species . But there is not a shadow of evidence in favour of this view : to assert that we could not breed ...
... slight devia- tions in their structure , in such case , I grant that we could deduce nothing from domestic varieties in regard to species . But there is not a shadow of evidence in favour of this view : to assert that we could not breed ...
Página 18
... slight , has had its wild prototype . At this rate there must have existed at least a score of species of wild cattle , as many sheep , and several goats in Europe alone , and several even within Great Britain . One author believes that ...
... slight , has had its wild prototype . At this rate there must have existed at least a score of species of wild cattle , as many sheep , and several goats in Europe alone , and several even within Great Britain . One author believes that ...
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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