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 30
... single variation from the aboriginal stock . We have proofs that this is not so in some cases , in which exact records have been kept ; thus , to give a very trifling instance , the steadily - increasing size of the common gooseberry ...
... single variation from the aboriginal stock . We have proofs that this is not so in some cases , in which exact records have been kept ; thus , to give a very trifling instance , the steadily - increasing size of the common gooseberry ...
Página 35
... single plant worth culture . It is not that these countries , so rich in species , do not by a strange chance possess the abori- ginal stocks of any useful plants , but that the native plants have not been improved by continued ...
... single plant worth culture . It is not that these countries , so rich in species , do not by a strange chance possess the abori- ginal stocks of any useful plants , but that the native plants have not been improved by continued ...
Página 46
... single instance , -the well - known one of the primrose and cowslip , or Primula vulgaris and veris . These plants differ con- siderably in appearance ; they have a different flavour , and emit a different odour ; they flower at ...
... single instance , -the well - known one of the primrose and cowslip , or Primula vulgaris and veris . These plants differ con- siderably in appearance ; they have a different flavour , and emit a different odour ; they flower at ...
Página 59
... single pair . Even slow - breeding man has doubled in twenty - five years , and at this rate , in a few thousand years , there would literally not be standing room for his progeny . Linnæus has calculated that if an annual plant ...
... single pair . Even slow - breeding man has doubled in twenty - five years , and at this rate , in a few thousand years , there would literally not be standing room for his progeny . Linnæus has calculated that if an annual plant ...
Página 61
... single one ; but this difference does not determine how many indi- viduals of the two species can be supported in a district . A large number of eggs is of some importance to those species which depend on a rapidly fluctuating amount of ...
... single one ; but this difference does not determine how many indi- viduals of the two species can be supported in a district . A large number of eggs is of some importance to those species which depend on a rapidly fluctuating amount of ...
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