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 x
... PIGEON'S WINGS . · SHORTENED BREASTBONE IN PIGEONS . SHORTENED FEET IN PIGEONS SHORTENED LEGS OF RABBITS BLIND CAVE ANIMALS · 49 53 55 62 64 • 70 70 • • 72 INHERITED HABITS . · 73 TAMENESS OF RABBITS . 76 MODIFICATIONS OBVIOUSLY ...
... PIGEON'S WINGS . · SHORTENED BREASTBONE IN PIGEONS . SHORTENED FEET IN PIGEONS SHORTENED LEGS OF RABBITS BLIND CAVE ANIMALS · 49 53 55 62 64 • 70 70 • • 72 INHERITED HABITS . · 73 TAMENESS OF RABBITS . 76 MODIFICATIONS OBVIOUSLY ...
Página 21
... pigeons , & c . ( many of the characters thus obtained being clearly independent of use and disuse ) , natural selection must be credited with similar powers , and Mr. Wallace concludes that Mr. Spencer's insuperable difficulty is THE ...
... pigeons , & c . ( many of the characters thus obtained being clearly independent of use and disuse ) , natural selection must be credited with similar powers , and Mr. Wallace concludes that Mr. Spencer's insuperable difficulty is THE ...
Página 62
... PIGEONS ' WINGS . Concerning pigeons ' wings Darwin says : “ As fancy pigeons are generally confined in aviaries of moderate size , and as even when not confined they do not search for their own food , they must during many generations ...
... PIGEONS ' WINGS . Concerning pigeons ' wings Darwin says : “ As fancy pigeons are generally confined in aviaries of moderate size , and as even when not confined they do not search for their own food , they must during many generations ...
Página 63
... pigeon for instance , and so might unconsciously be favoured by fanciers . The selection of elegant birds with longer necks or bodies would cause a relative reduction in the wings as with the Pouter , where the wings ... PIGEONS ' WINGS . 63.
... pigeon for instance , and so might unconsciously be favoured by fanciers . The selection of elegant birds with longer necks or bodies would cause a relative reduction in the wings as with the Pouter , where the wings ... PIGEONS ' WINGS . 63.
Página 64
... PIGEONS . The shortening of the sternum in pigeons is at- tributed to disuse of the flight muscles attached to it . The bone is only shortened by a third of an inch , but this represents a very remarkable reduction in proportional ...
... PIGEONS . The shortening of the sternum in pigeons is at- tributed to disuse of the flight muscles attached to it . The bone is only shortened by a third of an inch , but this represents a very remarkable reduction in proportional ...
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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.