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 82
... period of life ; and this period in the great majority of cases is an early one . If an animal can in any way protect its own eggs or young , a small number may be produced , and yet the average stock be fully kept up ; but if many eggs ...
... period of life ; and this period in the great majority of cases is an early one . If an animal can in any way protect its own eggs or young , a small number may be produced , and yet the average stock be fully kept up ; but if many eggs ...
Página 85
... period of its life , from enemies or from competitors for the same place and food ; and if these enemies or competitors be in the least degree favoured by any slight change of climate , they will increase in numbers ; and as each area ...
... period of its life , from enemies or from competitors for the same place and food ; and if these enemies or competitors be in the least degree favoured by any slight change of climate , they will increase in numbers ; and as each area ...
Página 105
... period of life , tend to reappear in the offspring at the same period ; -for in- stance , in the shape , size , and flavour of the seeds of the many varieties of our culinary and agricultural plants ; in the caterpillar and cocoon ...
... period of life , tend to reappear in the offspring at the same period ; -for in- stance , in the shape , size , and flavour of the seeds of the many varieties of our culinary and agricultural plants ; in the caterpillar and cocoon ...
Página 125
... periods of time for the work of natural selec- tion , she does not grant an indefinite period ; for as all organic beings are striving to seize on each place in the economy of nature , if any one species does not become modified and ...
... periods of time for the work of natural selec- tion , she does not grant an indefinite period ; for as all organic beings are striving to seize on each place in the economy of nature , if any one species does not become modified and ...
Página 133
... period . We have evidence of this , in the facts stated in the second chapter showing that it is the common and diffused or dominant species which offer the greatest number of re- corded varieties . Hence , rare species will be less ...
... period . We have evidence of this , in the facts stated in the second chapter showing that it is the common and diffused or dominant species which offer the greatest number of re- corded varieties . Hence , rare species will be less ...
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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