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 11
... light- est Australian jaw , either absolutely or ( in some cases ) relatively to the cranium . The uniformity of change relied upon by Mr. Spencer is scarcely borne out by the facts so far as male jaws are concerned . The great ...
... light- est Australian jaw , either absolutely or ( in some cases ) relatively to the cranium . The uniformity of change relied upon by Mr. Spencer is scarcely borne out by the facts so far as male jaws are concerned . The great ...
Página 59
... correct , since the exces- sive weight of the leg - bones increases the weight of the skeleton more than the diminished weight of the wing - bones reduces it . bones of the wild duck long and light . The DUCKS ' LEGS AND WINGS . 59.
... correct , since the exces- sive weight of the leg - bones increases the weight of the skeleton more than the diminished weight of the wing - bones reduces it . bones of the wild duck long and light . The DUCKS ' LEGS AND WINGS . 59.
Página 60
... light . The used leg - bones and the disused wing - bones have alike been shortened and thickened , though in different proportions . Natural or artificial selection might easily thicken legs without lengthening them , or shorten wings ...
... light . The used leg - bones and the disused wing - bones have alike been shortened and thickened , though in different proportions . Natural or artificial selection might easily thicken legs without lengthening them , or shorten wings ...
Página 73
... light with its various dangers and severer competition . Panmixia , however , as Weismann has shown , would probably be the most important factor in causing blindness . INHERITED HABITS . Darwin says : " A horse is trained to certain ...
... light with its various dangers and severer competition . Panmixia , however , as Weismann has shown , would probably be the most important factor in causing blindness . INHERITED HABITS . Darwin says : " A horse is trained to certain ...
Página 134
... light wings of birds , or the long legs and neck of the giraffe or crane . VARIED EFFECTS OF USE AND DISUSE . " " The changes which we somewhat roughly and empirically group together as the effects of use and disuse are of widely ...
... light wings of birds , or the long legs and neck of the giraffe or crane . VARIED EFFECTS OF USE AND DISUSE . " " The changes which we somewhat roughly and empirically group together as the effects of use and disuse are of widely ...
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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.