The Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for LifeD. Appleton, 1904 - 435 páginas |
Dentro del libro
Resultados 6-10 de 100
Página 16
... nearly mature ; peculiarities in the silkworm are known to ap- pear at the corresponding caterpillar or cocoon stage . But hereditary diseases and some other facts make me believe that the rule has a wider extension , and that , when ...
... nearly mature ; peculiarities in the silkworm are known to ap- pear at the corresponding caterpillar or cocoon stage . But hereditary diseases and some other facts make me believe that the rule has a wider extension , and that , when ...
Página 21
... several authors , that all the races belong to the same species . Having kept nearly all the English breeds of the fowl alive , having bred and crossed them , and examined their skeletons , CHAP . I. ] CHARACTER OF DOMESTIC VARIETIES . 21.
... several authors , that all the races belong to the same species . Having kept nearly all the English breeds of the fowl alive , having bred and crossed them , and examined their skeletons , CHAP . I. ] CHARACTER OF DOMESTIC VARIETIES . 21.
Página 32
... nearly all the breeders of the various domestic animals and the cultivators of plants , with whom I have conversed , or whose treatises I have read , are firmly convinced that the several breeds to which each has attended , are ...
... nearly all the breeders of the various domestic animals and the cultivators of plants , with whom I have conversed , or whose treatises I have read , are firmly convinced that the several breeds to which each has attended , are ...
Página 52
... nearly allied forms , and these alone bear on the question . If monstrous forms of this kind ever do appear in a state of nature and are capable of reproduction ( which is not always the case ) , as they occur rarely and singularly ...
... nearly allied forms , and these alone bear on the question . If monstrous forms of this kind ever do appear in a state of nature and are capable of reproduction ( which is not always the case ) , as they occur rarely and singularly ...
Página 67
... to the members of the same genus or class having nearly similar habits of life . With respect to the number of individuals or commonness of species , the comparison of course relates only to the CHAP . II . ] DOMINANT SPECIES VARY MOST .
... to the members of the same genus or class having nearly similar habits of life . With respect to the number of individuals or commonness of species , the comparison of course relates only to the CHAP . II . ] DOMINANT SPECIES VARY MOST .
Otras ediciones - Ver todas
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