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 vii
... cell - making instinct- Changes of instinct and structure not necessarily simultaneous - Difficulties of the theory of the Natural Selection of instincts - Neuter or sterile insects - Summary .. 191 CHAPTER IX . HYBRIDISM . Distinction ...
... cell - making instinct- Changes of instinct and structure not necessarily simultaneous - Difficulties of the theory of the Natural Selection of instincts - Neuter or sterile insects - Summary .. 191 CHAPTER IX . HYBRIDISM . Distinction ...
Página 93
... cells , or became attached to any supporting surface , his law " that homologous units of any order become differentiated in proportion as their relations to incident forces become different " would come into action . But as we have no ...
... cells , or became attached to any supporting surface , his law " that homologous units of any order become differentiated in proportion as their relations to incident forces become different " would come into action . But as we have no ...
Página 124
... cells , and which has practically anticipated the discoveries of profound mathematicians ? Fourthly , how can we account for species , when crossed , being sterile and producing sterile offspring , whereas , when varieties. 124 [ CHAP ...
... cells , and which has practically anticipated the discoveries of profound mathematicians ? Fourthly , how can we account for species , when crossed , being sterile and producing sterile offspring , whereas , when varieties. 124 [ CHAP ...
Página 135
... cells and covered by translu- cent skin , but without any lens or other refractive body . We may , however , according to M. Jourdain , descend even a step lower and find aggregates of pigment - cells , apparently serving as organs of ...
... cells and covered by translu- cent skin , but without any lens or other refractive body . We may , however , according to M. Jourdain , descend even a step lower and find aggregates of pigment - cells , apparently serving as organs of ...
Página 136
... cells , lying in a sack - like fold of the skin ; and the vitreous body is formed from embryonic sub - cutaneous tissue . To arrive , however , at a just conclusion regarding the formation of the eye , with all its marvel- lous yet not ...
... cells , lying in a sack - like fold of the skin ; and the vitreous body is formed from embryonic sub - cutaneous tissue . To arrive , however , at a just conclusion regarding the formation of the eye , with all its marvel- lous yet not ...
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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