The Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for LifeD. Appleton, 1904 - 435 páginas |
Dentro del libro
Resultados 1-5 de 100
Página xviii
... become changed into permanent species , which are no longer capable of intercrossing . 6 Rafinesque , in his New ... becoming species by assuming con- stant and peculiar characters ; " but farther on ( p . 18 ) he adds , " except the ...
... become changed into permanent species , which are no longer capable of intercrossing . 6 Rafinesque , in his New ... becoming species by assuming con- stant and peculiar characters ; " but farther on ( p . 18 ) he adds , " except the ...
Página xix
... become adapted to its peculiar habits of life . The work , from its powerful and brilliant style , though displaying in the earlier editions little accurate knowledge and a great want of scientific caution , imme- diately had a very ...
... become adapted to its peculiar habits of life . The work , from its powerful and brilliant style , though displaying in the earlier editions little accurate knowledge and a great want of scientific caution , imme- diately had a very ...
Página 27
... become wild or feral , though the dovecot - pigeon , which is the rock - pigeon in a very slightly altered state , has become feral in several places . Again , all recent experience shows that it is difficult to get wild animals to ...
... become wild or feral , though the dovecot - pigeon , which is the rock - pigeon in a very slightly altered state , has become feral in several places . Again , all recent experience shows that it is difficult to get wild animals to ...
Página 29
... become less and less , as in each suc ceeding generation there will be less of the foreign blood ; but when there has been no cross , and there is a tendency in the breed to revert to a CHAP . I. ] 29 DOMESTIC PIGEONS .
... become less and less , as in each suc ceeding generation there will be less of the foreign blood ; but when there has been no cross , and there is a tendency in the breed to revert to a CHAP . I. ] 29 DOMESTIC PIGEONS .
Página 30
... become anywhere feral ; -these species presenting certain very abnormal characters , as compared with all other Columbida , though so like the rock - pigeon in most respects ; the occasional re - appearance of the blue colour and ...
... become anywhere feral ; -these species presenting certain very abnormal characters , as compared with all other Columbida , though so like the rock - pigeon in most respects ; the occasional re - appearance of the blue colour and ...
Otras ediciones - Ver todas
Términos y frases comunes
adapted affinities allied species America ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common continent crossed crustaceans degree developed difficulty distinct species domestic doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids important individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living males mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs parent peculiar perfect pigeon pistil pollen present principle probably produced progenitor quadrupeds ranked remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed swimbladder tend theory tion trees variability variations varieties vary whilst whole wings young