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 34
... so little quarrelsome , with " everlasting layers " which never desire to sit , and with the bantam so small and elegant ; when we com- pare the host of agricultural , culinary , orchard , 34 [ CHAP . I. SELECTION BY MAN .
... so little quarrelsome , with " everlasting layers " which never desire to sit , and with the bantam so small and elegant ; when we com- pare the host of agricultural , culinary , orchard , 34 [ CHAP . I. SELECTION BY MAN .
Página 38
... never , the case . The law of correlated variation , the importance of which should never be overlooked , will ensure some differences ; but , as a general rule , it can- not be doubted that the continued selection of slight variations ...
... never , the case . The law of correlated variation , the importance of which should never be overlooked , will ensure some differences ; but , as a general rule , it can- not be doubted that the continued selection of slight variations ...
Página 39
... more methodically , did greatly modify , even during their lifetimes , the forms and qualities of their cattle . Slow and insensible . changes of this kind can never be recognised unless actual 5 CHAP . I. ] 39 UNCONSCIOUS SELECTION .
... more methodically , did greatly modify , even during their lifetimes , the forms and qualities of their cattle . Slow and insensible . changes of this kind can never be recognised unless actual 5 CHAP . I. ] 39 UNCONSCIOUS SELECTION .
Página 40
... never be recognised unless actual measurements or careful drawings of the breeds in question have been made long ago , which may serve for comparison . In some cases , however , unchanged , or but little changed individuals of the same ...
... never be recognised unless actual measurements or careful drawings of the breeds in question have been made long ago , which may serve for comparison . In some cases , however , unchanged , or but little changed individuals of the same ...
Página 41
... never have expected , or even wished , to produce the result which ensued - namely , the production of two distinct strains . The two flocks of Leicester sheep kept by Mr. Buckley and Mr. Burgess , as Mr. Youatt remarks , " have been ...
... never have expected , or even wished , to produce the result which ensued - namely , the production of two distinct strains . The two flocks of Leicester sheep kept by Mr. Buckley and Mr. Burgess , as Mr. Youatt remarks , " have been ...
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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