The Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for LifeD. Appleton, 1904 - 435 páginas |
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Página v
... vary most - Species of the larger genera in each country vary more frequently than the species of the smaller genera - Many of the species of the larger genera resemble varieties in being very closely , but unequally , related to each ...
... vary most - Species of the larger genera in each country vary more frequently than the species of the smaller genera - Many of the species of the larger genera resemble varieties in being very closely , but unequally , related to each ...
Página vii
... vary in an analogous manner - Reversions to long - lost characters - Summary Page 164 · CHAPTER VI . DIFFICULTIES OF THE THEORY . Difficulties of the theory of descent with modification - Absence or rarity of transitional varieties ...
... vary in an analogous manner - Reversions to long - lost characters - Summary Page 164 · CHAPTER VI . DIFFICULTIES OF THE THEORY . Difficulties of the theory of descent with modification - Absence or rarity of transitional varieties ...
Página xvi
... vary in some degree , and , secondly , that agri- culturists improve their domesticated animals by selec- tion ; and then , he adds , but what is done in this latter case " by art , seems to be done with equal efficacy , though more ...
... vary in some degree , and , secondly , that agri- culturists improve their domesticated animals by selec- tion ; and then , he adds , but what is done in this latter case " by art , seems to be done with equal efficacy , though more ...
Página 5
... vary how- ever slightly in any manner profitable to itself , under the complex and sometimes varying conditions of life , will have a better chance of surviving , and thus be naturally selected . From the strong principle of inheri ...
... vary how- ever slightly in any manner profitable to itself , under the complex and sometimes varying conditions of life , will have a better chance of surviving , and thus be naturally selected . From the strong principle of inheri ...
Página 8
... vary , it generally continues varying for many generations . No case is on record of a variable organism ceasing to vary under cultivation . Our oldest cultivated plants , such as wheat , still yield new varieties : our oldest ...
... vary , it generally continues varying for many generations . No case is on record of a variable organism ceasing to vary under cultivation . Our oldest cultivated plants , such as wheat , still yield new varieties : our oldest ...
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Términos y frases comunes
adapted affinities allied species America ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common continent crossed crustaceans degree developed difficulty distinct species domestic doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids important individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living males mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs parent peculiar perfect pigeon pistil pollen present principle probably produced progenitor quadrupeds ranked remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed swimbladder tend theory tion trees variability variations varieties vary whilst whole wings young