The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
Dentro del libro
Resultados 1-5 de 88
Página xiv
... seems to have been chiefly led to his conclusion on the gradual change of species , by the diffi- culty of distinguishing species and varieties , by the almost perfect gradation of forms in certain groups , and by the analogy of ...
... seems to have been chiefly led to his conclusion on the gradual change of species , by the diffi- culty of distinguishing species and varieties , by the almost perfect gradation of forms in certain groups , and by the analogy of ...
Página xv
... seems to be done with equal efficacy , though more slowly , by nature , in the formation of varieties of mankind , fitted for the country which they inhabit . Of the accidental varieties of man , which would occur among the first few ...
... seems to be done with equal efficacy , though more slowly , by nature , in the formation of varieties of mankind , fitted for the country which they inhabit . Of the accidental varieties of man , which would occur among the first few ...
Página xvi
... seems to consider that the world was nearly depopulated at successive periods , and then re - stocked ; and he gives as an alternative , that new forms may be generated " without the presence of any mould or germ of former aggregates ...
... seems to consider that the world was nearly depopulated at successive periods , and then re - stocked ; and he gives as an alternative , that new forms may be generated " without the presence of any mould or germ of former aggregates ...
Página xx
... seems that Bory St. Vincent , Burdach , Poiret , and Fries , have all admitted that new species are continually being produced . I may add , that of the thirty - four authors named in this Historical Sketch , who believe in the ...
... seems that Bory St. Vincent , Burdach , Poiret , and Fries , have all admitted that new species are continually being produced . I may add , that of the thirty - four authors named in this Historical Sketch , who believe in the ...
Página 5
... seems clear that organic beings must be exposed during several generations to new conditions to cause any great amount of variation ; and that , when the organisation has once begun to vary , it generally continues varying for many ...
... seems clear that organic beings must be exposed during several generations to new conditions to cause any great amount of variation ; and that , when the organisation has once begun to vary , it generally continues varying for many ...
Otras ediciones - Ver todas
Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young