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 29
... belonging to the same genus . So with plants , the seeds of the different varie- ties of the bean or maize probably differ more in size , than do the seeds of the distinct species in any one genus in the same two families . The same ...
... belonging to the same genus . So with plants , the seeds of the different varie- ties of the bean or maize probably differ more in size , than do the seeds of the distinct species in any one genus in the same two families . The same ...
Página 38
... belonging to the oak family , at least two - thirds are provisional species , that is , are not known strictly to fulfil the definition above given of a true species . It should be added that De Candolle no longer believes that species ...
... belonging to the oak family , at least two - thirds are provisional species , that is , are not known strictly to fulfil the definition above given of a true species . It should be added that De Candolle no longer believes that species ...
Página 41
... belong . Again , plants low in the scale of organisation are generally much more widely diffused than plants higher in the scale ; and here again there is no close relation to the size of the genera . The cause of lowly- organised ...
... belong . Again , plants low in the scale of organisation are generally much more widely diffused than plants higher in the scale ; and here again there is no close relation to the size of the genera . The cause of lowly- organised ...
Página 43
... belong range over 14 : 3 provinces . So that the acknowledged varieties have nearly the same restricted average range , as have the closely allied forms , marked for me by Mr. Watson as doubtful species , but which are almost ...
... belong range over 14 : 3 provinces . So that the acknowledged varieties have nearly the same restricted average range , as have the closely allied forms , marked for me by Mr. Watson as doubtful species , but which are almost ...
Página 73
... belonging to all Orders have their sexes more often separated than other plants , I find to be the case in this country ; and at my request Dr. Hooker tabulated the trees of New Zealand , and Dr. Asa Gray those of the United States ...
... belonging to all Orders have their sexes more often separated than other plants , I find to be the case in this country ; and at my request Dr. Hooker tabulated the trees of New Zealand , and Dr. Asa Gray those of the United States ...
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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