The Origin of Species by Means of Natural Selection, Or, The Preservation of Favored Races in the Struggle for Life, Tema 4D. Appleton, 1896 - 365 páginas |
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Página 62
... Asa Gray has remarked in commenting on this memoir , such as generally enter into specific definitions . De Candolle then goes on to say that he gives the rank of species to the forms that differ by characters never varying on the same ...
... Asa Gray has remarked in commenting on this memoir , such as generally enter into specific definitions . De Candolle then goes on to say that he gives the rank of species to the forms that differ by characters never varying on the same ...
Página 63
... Asa Gray again remarks , if these connecting forms which are now rare , were to become wholly extinct , the three sub - species would hold exactly the same relation to each other , as do the four or five provisionally admitted species ...
... Asa Gray again remarks , if these connecting forms which are now rare , were to become wholly extinct , the three sub - species would hold exactly the same relation to each other , as do the four or five provisionally admitted species ...
Página 98
Charles Darwin. our domestic productions , is not directly produced , as Hooker and Asa Gray have well remarked , by man ; he can neither originate varieties , nor prevent their occur- rence ; he can only preserve and accumulate such as ...
Charles Darwin. our domestic productions , is not directly produced , as Hooker and Asa Gray have well remarked , by man ; he can neither originate varieties , nor prevent their occur- rence ; he can only preserve and accumulate such as ...
Página 116
... Asa Gray , in an exactly intermediate condition , or , as he expresses it , are more or less diœciously polygamous . Let us now turn to the nectar - feeding insects ; we may suppose the plant , of which we have been slowly increasing ...
... Asa Gray , in an exactly intermediate condition , or , as he expresses it , are more or less diœciously polygamous . Let us now turn to the nectar - feeding insects ; we may suppose the plant , of which we have been slowly increasing ...
Página 123
... Asa Gray those of the United States , and the result was as I anticipated . On the other hand , Dr. Hooker informs me that the rule does not hold good in Australia : but if most of the Australian trees are dichogamous , the same result ...
... Asa Gray those of the United States , and the result was as I anticipated . On the other hand , Dr. Hooker informs me that the rule does not hold good in Australia : but if most of the Australian trees are dichogamous , the same result ...
Términos y frases comunes
acquired adapted advantage allied analogous animals and plants appear Asa Gray beak become bees believe birds breeds caudicle cause cells characters climate closely colour common crossed cuckoo degree developed difficulty distinct species disuse divergence domestic animals domestic races doubt effects eggs existence extinct extremely facts favourable females flowers forms Fritz Müller genera genus giraffe gradations greater number groups habits Hence hermaphrodites hive-bee important improved increase in number inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ large number larger genera larvæ less likewise males manner Melipona Mivart natural selection naturalists nearly nest occasionally offspring organisation organs origin Origin of Species perfect period pigeons pollen pollen-grains present preserved principle probably produced progenitor quadrupeds rank Red Grouse relation remarked resemble rock-pigeon seeds sexes sexual sexual selection slight stamens striped structure struggle supposed swimbladder tend tendency tion transitional tree variability variations varieties vary widely wings young