On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
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Página 12
... cause having acted on both ; but when amongst individuals , apparently exposed to the same conditions , any very rare deviation , due to some extraordinary combination of circumstances , appears in the parent - say , once amongst ...
... cause having acted on both ; but when amongst individuals , apparently exposed to the same conditions , any very rare deviation , due to some extraordinary combination of circumstances , appears in the parent - say , once amongst ...
Página 13
... cause , which may have acted on the ovules or male element ; in nearly the same manner as in the crossed offspring from a short - horned cow by a long - horned bull , the greater length of horn , though appearing late in life , is ...
... cause , which may have acted on the ovules or male element ; in nearly the same manner as in the crossed offspring from a short - horned cow by a long - horned bull , the greater length of horn , though appearing late in life , is ...
Página 39
... causing variability . I do not believe that variability is an inherent and necessary contingency , under all circumstances , with all organic beings , as some authors have thought . The effects of variability are modified by various ...
... causing variability . I do not believe that variability is an inherent and necessary contingency , under all circumstances , with all organic beings , as some authors have thought . The effects of variability are modified by various ...
Página 40
... causes of Change I am convinced that the accumulative action of Selection , whether applied methodically and more quickly , or unconsciously and more slowly , but more efficiently , is by far the pre- dominant Power . CHAPTER II ...
... causes of Change I am convinced that the accumulative action of Selection , whether applied methodically and more quickly , or unconsciously and more slowly , but more efficiently , is by far the pre- dominant Power . CHAPTER II ...
Página 46
... cause closely attract his attention , varieties of it will almost universally be found recorded . These varieties , moreover , will be often ranked by some authors as species . Look at the common oak , how closely it has been studied ...
... cause closely attract his attention , varieties of it will almost universally be found recorded . These varieties , moreover , will be often ranked by some authors as species . Look at the common oak , how closely it has been studied ...
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Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely