Are the Effects of Use and Disuse Inherited?: An Examination of the View Held by Spencer and DarwinMacmillan, 1890 - 156 páginas |
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Página 7
... bones during ages of brutal violence might bring about a change in this direction . Lightness of structure , facilitating agility and being economical of material , would also be favoured by natural selection SO far as strength was not ...
... bones during ages of brutal violence might bring about a change in this direction . Lightness of structure , facilitating agility and being economical of material , would also be favoured by natural selection SO far as strength was not ...
Página 9
... maintain or develop . the projecting chin , increase its perpendicular height till the jaw is deepest and strongest at its extremity , evolve a side flange , and enlarge the upper jaw - bone to form part of a DIMINUTION OF THE JAWS . 9.
... maintain or develop . the projecting chin , increase its perpendicular height till the jaw is deepest and strongest at its extremity , evolve a side flange , and enlarge the upper jaw - bone to form part of a DIMINUTION OF THE JAWS . 9.
Página 10
... bone to form part of a more prominent nose , while drawing back the savagely obtrusive teeth and lips to a more pleasing ' and subdued position of retirement and of humanized beauty . If human preference and natural selection caused ...
... bone to form part of a more prominent nose , while drawing back the savagely obtrusive teeth and lips to a more pleasing ' and subdued position of retirement and of humanized beauty . If human preference and natural selection caused ...
Página 56
... bones , & c . , of wild and tame ducks similarly reared . If individual disuse diminished the weight of the duck's wing - bones by 9 per cent . there would be nothing left to account for . I suspect that investigation would reveal ano ...
... bones , & c . , of wild and tame ducks similarly reared . If individual disuse diminished the weight of the duck's wing - bones by 9 per cent . there would be nothing left to account for . I suspect that investigation would reveal ano ...
Página 57
... bones of the Penguin duck have slightly diminished in length , although they have in- creased 39 per cent . in weight . " Relatively to the weight of the skeleton , the leg - bones have shortened in the tame breeds of ducks by over 5 ...
... bones of the Penguin duck have slightly diminished in length , although they have in- creased 39 per cent . in weight . " Relatively to the weight of the skeleton , the leg - bones have shortened in the tame breeds of ducks by over 5 ...
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Términos y frases comunes
acquired characters acquired modifications alleged Animals and Plants appears artificial selection atavism attributed Aylesbury duck become birds bones breeds cause cent civilization concomitant variation Contemporary Review Crown 8vo cumulative Darwin Descent deterioration diminished diminution diseases domestic animals domestic rabbit duck effects of ancestral effects of disuse enlarged epilepsy evidence evil explanation eyes fact factor of evolution fancy pigeons father favoured Francis Darwin Francis Galton Galton gemmules guinea-pigs heredity Illustrations improvement incisors increased individual inherited effects inherited injuries inherited mutilations insects instances instincts jaws Lamarckian leg-bones legs lengthened muscles natural or artificial natural selection nervous neuter offspring organs Origin of Species pangenesis panmixia parents pigeons Plants under Domestication quasi-inheritance race Ray Lankester reduced wings relative reproductive elements sexual selection shortened Spencer spite of disuse spontaneous variations sternum structure suppose tameness teeth tend tendency theory thickened sole tion toes transmit true inheritance use-inheritance Variation of Animals weight Weismann wing-bones
Pasajes populares
Página 26 - For peculiar habits confined to the workers or sterile females, however long they might be followed, could not possibly affect the males and fertile females, which alone leave descendants. I am surprised that no one has hitherto advanced this demonstrative case of neuter insects, against the well-known doctrine of inherited habit, as advanced by Lamarck.