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 32
... never be recognised unless actual measurements or careful drawings of the breeds in question had been made long ago , which might serve for comparison . In some cases , however , unchanged , or but little changed individuals of the same ...
... never be recognised unless actual measurements or careful drawings of the breeds in question had been made long ago , which might serve for comparison . In some cases , however , unchanged , or but little changed individuals of the same ...
Página 33
... never have expected or even have wished to have pro- duced the result which ensued - namely , the production of two distinct strains . The two flocks of Leicester sheep kept by Mr. Buckley and Mr. Burgess , as Mr. Youatt re- marks ...
... never have expected or even have wished to have pro- duced the result which ensued - namely , the production of two distinct strains . The two flocks of Leicester sheep kept by Mr. Buckley and Mr. Burgess , as Mr. Youatt re- marks ...
Página 34
... never thought what splendid fruit we should eat ; though we owe our excellent fruit , in some small degree , to their having naturally chosen and preserved the best varieties they could anywhere find . A large amount of change in our ...
... never thought what splendid fruit we should eat ; though we owe our excellent fruit , in some small degree , to their having naturally chosen and preserved the best varieties they could anywhere find . A large amount of change in our ...
Página 35
... is internal . He can never act by selection , ex- cepting on variations which are first given to him in some slight degree by nature . No man would ever try to make a fantail , till he saw a pigeon VARIATION UNDER DOMESTICATION 35.
... is internal . He can never act by selection , ex- cepting on variations which are first given to him in some slight degree by nature . No man would ever try to make a fantail , till he saw a pigeon VARIATION UNDER DOMESTICATION 35.
Página 36
... never dreamed what the descendants of that pigeon would become through long - continued , partly unconscious and partly methodical selection . Perhaps the parent bird of all fantails had only fourteen tail - feathers some- what expanded ...
... never dreamed what the descendants of that pigeon would become through long - continued , partly unconscious and partly methodical selection . Perhaps the parent bird of all fantails had only fourteen tail - feathers some- what expanded ...
Otras ediciones - Ver todas
On the Origin of Species by Means of Natural Selection: or the Preservation ... Charles Darwin Vista previa limitada - 2023 |
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