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 231
... reciprocal cross between two species , I mean the case , for instance , of a stallion - horse being first crossed ... crosses . Such cases are highly important , for they prove that the capacity in any two species to cross is often com ...
... reciprocal cross between two species , I mean the case , for instance , of a stallion - horse being first crossed ... crosses . Such cases are highly important , for they prove that the capacity in any two species to cross is often com ...
Página 232
Or The Preservation of Favoured Races in the Struggle for Life Charles Darwin. reciprocal crosses between the same two species was long ago observed by Kölreuter . To give an instance : Mirabilis jalapa can easily be fertilised by the ...
Or The Preservation of Favoured Races in the Struggle for Life Charles Darwin. reciprocal crosses between the same two species was long ago observed by Kölreuter . To give an instance : Mirabilis jalapa can easily be fertilised by the ...
Página 233
... cross between any two species is not always governed by their systematic affinity or degree of resemblance to each other . This latter statement is clearly proved by reciprocal crosses between the same two species , for according as the ...
... cross between any two species is not always governed by their systematic affinity or degree of resemblance to each other . This latter statement is clearly proved by reciprocal crosses between the same two species , for according as the ...
Página 234
... crosses and of hybrids is simply incidental or dependent on unknown differences , chiefly in the repro- ductive systems , of the species which are crossed . The differences being of so peculiar and limited a nature , that , in reciprocal ...
... crosses and of hybrids is simply incidental or dependent on unknown differences , chiefly in the repro- ductive systems , of the species which are crossed . The differences being of so peculiar and limited a nature , that , in reciprocal ...
Página 235
... reciprocal crosses , the facility of effecting an union is often very far from equal , so it sometimes is in grafting ; the common gooseberry , for instance , cannot be grafted on the currant , whereas the currant will take , though ...
... reciprocal crosses , the facility of effecting an union is often very far from equal , so it sometimes is in grafting ; the common gooseberry , for instance , cannot be grafted on the currant , whereas the currant will take , though ...
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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