On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeEaston Press, 1976 - 470 páginas |
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Página xviii
... seems to have been chiefly led to his conclusion on the gradual change of species , by the difficulty of distinguishing species and varieties , by the almost perfect gradation of forms in certain groups , and by the analogy of domestic ...
... seems to have been chiefly led to his conclusion on the gradual change of species , by the difficulty of distinguishing species and varieties , by the almost perfect gradation of forms in certain groups , and by the analogy of domestic ...
Página xx
... 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 pre- sence 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 pre- sence of any mould or germ of former aggregates ...
Página 146
... seems plainer than that the long toes , not furnished with membrane of the Grallatores are formed for walking over swamps and floating plants ? —the water - hen and landrail are members of this order , yet the first is nearly as aquatic ...
... seems plainer than that the long toes , not furnished with membrane of the Grallatores are formed for walking over swamps and floating plants ? —the water - hen and landrail are members of this order , yet the first is nearly as aquatic ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
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Términos y frases comunes
accumulated adapted admit affinities allied species America ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number groups of species habits Hence hybrids hybrids produced 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 offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds slight South America stamens sterility structure struggle successive supposed swimbladder theory variability variations varieties vary whilst whole wings young