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 29
... closely allied sub- breeds . And when a cross has been made , the closest selection is far more indispensable even than in ordi- nary cases . If selection consisted merely in separating some very distinct variety , and breeding from it ...
... closely allied sub- breeds . And when a cross has been made , the closest selection is far more indispensable even than in ordi- nary cases . If selection consisted merely in separating some very distinct variety , and breeding from it ...
Página 41
... closely , but unequally , related to each other , and in having restricted ranges . BEFORE applying the principles arrived at in the last chapter to organic beings in a state of nature , we must briefly discuss whether these latter are ...
... closely , but unequally , related to each other , and in having restricted ranges . BEFORE applying the principles arrived at in the last chapter to organic beings in a state of nature , we must briefly discuss whether these latter are ...
Página 43
... closely similar to some other forms , or are so closely linked to them by intermediate gradations , that naturalists do not like to rank them as distinct species , V are in several respects the most important for us VARIATION UNDER NATURE ...
... closely similar to some other forms , or are so closely linked to them by intermediate gradations , that naturalists do not like to rank them as distinct species , V are in several respects the most important for us VARIATION UNDER NATURE ...
Página 44
... closely - allied 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 ...
... closely - allied 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 ...
Página 46
... closely attract his attention , varieties of it will almost universally be found recorded . These varieties , moreover , will be often ranked by some authors as species . Look at the common oak , how closely it has been studied ; 46 ON ...
... closely attract his attention , varieties of it will almost universally be found recorded . These varieties , moreover , will be often ranked by some authors as species . Look at the common oak , how closely it has been studied ; 46 ON ...
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