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 34
... we cannot recognise , and therefore do not know , the wild parent - stocks of the plants which have been longest cultivated in our flower and kitchen gardens . If it has taken centuries or thousands of 34 ON THE ORIGIN OF SPECIES.
... we cannot recognise , and therefore do not know , the wild parent - stocks of the plants which have been longest cultivated in our flower and kitchen gardens . If it has taken centuries or thousands of 34 ON THE ORIGIN OF SPECIES.
Página 46
... flower at slightly different periods ; they grow in somewhat different stations ; they ascend mountains to different heights ; they have different geographical ranges ; and lastly , according to very numerous experiments made during ...
... flower at slightly different periods ; they grow in somewhat different stations ; they ascend mountains to different heights ; they have different geographical ranges ; and lastly , according to very numerous experiments made during ...
Página 68
... flower . From experiments which I have lately tried , I have found that the visits of bees are necessary for the ... flowers in that district ! In the case of every species , many different checks , acting at different periods of ...
... flower . From experiments which I have lately tried , I have found that the visits of bees are necessary for the ... flowers in that district ! In the case of every species , many different checks , acting at different periods of ...
Página 83
... flower . In this case insects in seeking the nectar would get dusted with pollen , and would certainly often transport the pollen from one flower to the stigma of another flower . The flowers of two distinct individuals of the same ...
... flower . In this case insects in seeking the nectar would get dusted with pollen , and would certainly often transport the pollen from one flower to the stigma of another flower . The flowers of two distinct individuals of the same ...
Página 84
... flower to flower , would likewise be favoured or selected . We might have taken the case of insects visiting flowers for the sake of collecting pollen instead of nectar ; and as pollen is formed for the sole object of fertilisation ...
... flower to flower , would likewise be favoured or selected . We might have taken the case of insects visiting flowers for the sake of collecting pollen instead of nectar ; and as pollen is formed for the sole object of fertilisation ...
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