The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página 38
... theory is the most natural one , " and the most accordant with the known facts in palæontology , geographical botany and zoology , of anatomical structure and classification . " When a young naturalist commences the study of a group of ...
... theory is the most natural one , " and the most accordant with the known facts in palæontology , geographical botany and zoology , of anatomical structure and classification . " When a young naturalist commences the study of a group of ...
Página 42
... theory ; inasmuch as geology plainly tells us that small genera have in the lapse of time often increased greatly in size ; and that large genera have often come to their maxima , decline , and disappeared . All that we want to show is ...
... theory ; inasmuch as geology plainly tells us that small genera have in the lapse of time often increased greatly in size ; and that large genera have often come to their maxima , decline , and disappeared . All that we want to show is ...
Página 119
... theory , sometimes to find the varying offspring of a species assuming characters which are already present in other members of the same group . And this undoubtedly is the case . The difficulty in distinguishing variable species is ...
... theory , sometimes to find the varying offspring of a species assuming characters which are already present in other members of the same group . And this undoubtedly is the case . The difficulty in distinguishing variable species is ...
Página 124
... THEORY . Difficulties of the theory of descent with modification - Absence or rarity of transitional varieties - Transitions in habits of life - Diversified habits in the same species - Species with habits widely different from those of ...
... THEORY . Difficulties of the theory of descent with modification - Absence or rarity of transitional varieties - Transitions in habits of life - Diversified habits in the same species - Species with habits widely different from those of ...
Página 125
... theory innumerable transitional forms must have existed , why do we not find them embedded in countless numbers in the crust of the earth ? It will be more convenient to discuss this question in the chapter on the Imperfection of the ...
... theory innumerable transitional forms must have existed , why do we not find them embedded in countless numbers in the crust of the earth ? It will be more convenient to discuss this question in the chapter on the Imperfection of the ...
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young