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 9
... cent . This slight reduction may be much more than accounted for by such causes as disuse in the individual , human preference setting back the teeth , and partial transference of the much more marked diminution seen in female jaws ...
... cent . This slight reduction may be much more than accounted for by such causes as disuse in the individual , human preference setting back the teeth , and partial transference of the much more marked diminution seen in female jaws ...
Página 56
... cent . there would be nothing left to account for . I suspect that investigation would reveal ano- malies inconsistent with the theory of use- inheritance . Thus according to Darwin's tables of comparative weights 56 ARE THE EFFECTS OF ...
... cent . there would be nothing left to account for . I suspect that investigation would reveal ano- malies inconsistent with the theory of use- inheritance . Thus according to Darwin's tables of comparative weights 56 ARE THE EFFECTS OF ...
Página 57
... cent . in weight . " Relatively to the weight of the skeleton , the leg - bones have shortened in the tame breeds of ducks by over 5 per cent . ( and in two breeds by over 8 per cent . ) although they have increased more than 28 per cent ...
... cent . in weight . " Relatively to the weight of the skeleton , the leg - bones have shortened in the tame breeds of ducks by over 5 per cent . ( and in two breeds by over 8 per cent . ) although they have increased more than 28 per cent ...
Página 58
... cent . more than in the shortened legs , and it amounts to II per cent . as compared with the weight of the skeleton . Such a shortening should represent a reduction of 29 per cent . in weight , whereas the actual reduction in the ...
... cent . more than in the shortened legs , and it amounts to II per cent . as compared with the weight of the skeleton . Such a shortening should represent a reduction of 29 per cent . in weight , whereas the actual reduction in the ...
Página 59
... cent . , and partly to a shortening of about 15 per cent . Carefully calculated , the reduction of the weight of the wing- bones in this breed is only 8.3 per cent . relatively to the whole skeleton , or only 5 per cent . relatively to ...
... cent . , and partly to a shortening of about 15 per cent . Carefully calculated , the reduction of the weight of the wing- bones in this breed is only 8.3 per cent . relatively to the whole skeleton , or only 5 per cent . relatively to ...
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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.