Charles Darwin's Works: The origin of species by means of natural selection...with additions and corrections from 6th and last English edD. Appleton, 1896 |
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Página vi
... characters of trifling importance - its power at all ages and on both sexes - Sexual selection - On the generality ... Character , related to the diversity of inhabitants of any small area , and to naturalisation - Action of Natural ...
... characters of trifling importance - its power at all ages and on both sexes - Sexual selection - On the generality ... Character , related to the diversity of inhabitants of any small area , and to naturalisation - Action of Natural ...
Página vii
... characters more variable than generic : secondary sexual characters variable - Species of the same genus vary in an analogous manner - Reversions to long - lost characters - Summary ... Page 164 CHAPTER VI . DIFFICULTIES OF THE THEORY ...
... characters more variable than generic : secondary sexual characters variable - Species of the same genus vary in an analogous manner - Reversions to long - lost characters - Summary ... Page 164 CHAPTER VI . DIFFICULTIES OF THE THEORY ...
Página xvi
... characters alone . After remarking that negroes and mulattoes enjoy an immunity from certain tropical diseases , he observes , firstly , that all animals tend to vary in some degree , and , secondly , that agri- culturists improve their ...
... characters alone . After remarking that negroes and mulattoes enjoy an immunity from certain tropical diseases , he observes , firstly , that all animals tend to vary in some degree , and , secondly , that agri- culturists improve their ...
Página xviii
... characters ; " but farther on ( p . 18 ) he adds , " except the original types or ancestors of the genus . " In 1843-44 Professor Haldeman ( Boston Journal of Nat . Hist . U. States , ' vol . iv . p . 468 ) has ably given the arguments ...
... characters ; " but farther on ( p . 18 ) he adds , " except the original types or ancestors of the genus . " In 1843-44 Professor Haldeman ( Boston Journal of Nat . Hist . U. States , ' vol . iv . p . 468 ) has ably given the arguments ...
Página xxii
... characters " sont fixés , pour chaque espèce , tant qu'elle se perpétue au milieu des mêmes circonstances : ils se modifient , si les circonstances ambiantes viennent à changer . ” " En résumé , l'observation des animaux sauvages ...
... characters " sont fixés , pour chaque espèce , tant qu'elle se perpétue au milieu des mêmes circonstances : ils se modifient , si les circonstances ambiantes viennent à changer . ” " En résumé , l'observation des animaux sauvages ...
Términos y frases comunes
acquired adapted advantage allied analogous appear Asa Gray beak become bees believe birds breeds caudicle cause cells characters climate closely colour common correlated crossed cuckoo degree developed difficulty distinct species disuse domestic animals domestic races doubt effects eggs existence extinct extremely facts favourable females flowers forms Fritz Müller genera genus giraffe gradations greater number groups habits Hence hermaphrodites hive-bee important improved increase in number individual differences inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ large number larger genera larvæ less likewise males manner Melipona Mivart natural selection naturalists nearly nest occasionally offspring organisation organs origin Origin of Species parent perfect period pigeons pollen pollen-grains present preserved principle probably produced progenitor quadrupeds rank Red Grouse relation remarked resemble rock-pigeon seeds sexes sexual sexual selection slight stamens sterile structure struggle supposed swimbladder tend tendency tion transitional tree variability variations varieties vary widely wings young
Pasajes populares
Página 77 - We behold the face of nature bright with gladness, we often see superabundance of food ; we do not see or we forget, that the birds which are idly singing round us mostly live on insects or seeds, and are thus constantly destroying life ; or we forget how largely these songsters, or their eggs, or their nestlings, are destroyed by birds and beasts of prey...
Página 109 - ... perform strange antics before the females, which, standing by as spectators, at last choose the most attractive partner. Those who have closely attended to birds in confinement well know that they often take individual preferences and dislikes; thus Sir R. Heron has described how a pied peacock was eminently attractive to all his hen birds.
Página 229 - If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.
Página 1 - These facts seemed to me to throw some light on the origin of species — that mystery of mysteries, as it has been called by one of our greatest philosophers.
Página 162 - ... of the former and present buds by ramifying branches may well represent the classification of all extinct and living species in groups subordinate to groups. Of the many twigs which flourished when the tree was a mere bush, only two or three, now grown into great branches, yet survive and bear the other branches ; so with the species which lived during long-past geological periods, very few have left living and modified descendants.
Página 203 - Our ignorance of the laws of variation is profound. Not in one case out of a hundred can we pretend to assign any reason why this or that part differs, more or less, from the same part in the parents.
Página 77 - I have called this principle, by which each slight variation, if useful, is preserved, by the term natural selection, in order to mark its relation to man's power of selection. But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient.
Página 163 - From the first growth of the tree, many a limb and branch has decayed and dropped off; and these lost branches of various sizes may represent those whole orders, families, and genera which have now no living representatives, and which are known to us only from having been found in a fossil state.
Página 244 - Why should not Nature take a sudden leap from structure to structure? On the theory of natural selection, we can clearly understand why she should not; for natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps.
Página 138 - The truth of the principle, that the greatest amount of life can be supported by great diversification of structure^ is seen under many natural circumstances. In an extremely small area, especially if freely open to immigration, and where the contest between individual and individual must be severe, we always find great diversity in its inhabitants. For instance, I found that a piece of turf, three feet by four in size, which had been...