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 4
... tend to be transmitted , if the use or disuse of organs or faculties does not similarly affect posterity by inheritance , then it is evident that no innate improvement in the race can take place without the aid of natural or artificial ...
... tend to be transmitted , if the use or disuse of organs or faculties does not similarly affect posterity by inheritance , then it is evident that no innate improvement in the race can take place without the aid of natural or artificial ...
Página 8
... tend to eliminate huge jaws and ferocious teeth when these were no longer needed as weapons of war or organs of prehension , & c . We can hardly assume that the lower half of the face is specially exempt from the influence of natural ...
... tend to eliminate huge jaws and ferocious teeth when these were no longer needed as weapons of war or organs of prehension , & c . We can hardly assume that the lower half of the face is specially exempt from the influence of natural ...
Página 21
... tend to vary to- gether , coincident variation is not necessary . The lengthened wing might be gained in one genera- tion , and the strengthened muscle at a subse- quent period ; the bird in the meanwhile drawing upon its surplus energy ...
... tend to vary to- gether , coincident variation is not necessary . The lengthened wing might be gained in one genera- tion , and the strengthened muscle at a subse- quent period ; the bird in the meanwhile drawing upon its surplus energy ...
Página 24
... tends to make the jaws and teeth unwork- able through the overcrowding and decay of the teeth - there being , as his illustrations show , no simultaneous or concomitant or proportional variation in relation to altered degree of use or ...
... tends to make the jaws and teeth unwork- able through the overcrowding and decay of the teeth - there being , as his illustrations show , no simultaneous or concomitant or proportional variation in relation to altered degree of use or ...
Página 41
... most susceptible of culture . The reproductive elements are also disturbed and modified in innumerable minor ways . Changed conditions or habits tend to produce a general " plasticity " " of type , the DIVERSE INHERITANCE . 4I.
... most susceptible of culture . The reproductive elements are also disturbed and modified in innumerable minor ways . Changed conditions or habits tend to produce a general " plasticity " " of type , the DIVERSE INHERITANCE . 4I.
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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.