On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeJ. Murray, 1860 - 502페이지 "In considering the Origin of Species, it is quite conceivable that a naturalist, reflecting on the mutual affinities of organic beings, on their embryological relations, their geographical distribution, geological succession, and other such facts, might come to the conclusion that each species had not been independently created, but had descended, like varieties, from other species. Nevertheless, such a conclusion, even if well founded, would be unsatisfactory, until it could be shown how the innumerable species inhabiting this world have been modified, so as to acquire that perfection of structure and coadaptation which most justly excites our admiration. Naturalists continually refer to external conditions, such as climate, food, & c, as the only possible cause of variation. In one very limited sense, as we shall hereafter see, this may be true; but it is preposterous to attribute to mere external conditions, the structure, for instance, of the woodpecker, with its feet, tail, beak, and tongue, so admirably adapted to catch insects under the bark of trees. In the case of the misseltoe, which draws its nourishment from certain trees, which has seeds that must be transported by certain birds, and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen from one flower to the other, it is equally preposterous to account for the structure of this parasite, with its relations to several distinct organic beings, by the effects of external conditions, or of habit, or of the volition of the plant itself"--Introduction. (PsycINFO Database Record (c) 2012 APA, all rights reserved) |
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12 페이지
... become plastic , and tends to depart in some small degree from that of the parental type . Any variation which is not inherited is unimportant for us . But the number and diversity of inheritable deviations of structure , both those of ...
... become plastic , and tends to depart in some small degree from that of the parental type . Any variation which is not inherited is unimportant for us . But the number and diversity of inheritable deviations of structure , both those of ...
24 페이지
... 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 most difficult to get any wild animal ...
... 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 most difficult to get any wild animal ...
26 페이지
... 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 with a distinct breed , and there is a tendency in both parents to revert to a character , which has ...
... 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 with a distinct breed , and there is a tendency in both parents to revert to a character , which has ...
32 페이지
... become an eminent breeder . If gifted with these qualities , and he studies his subject for years , and devotes his lifetime to it with indomitable perseverance , he will succeed , and may make great improvements ; if he wants any of ...
... become an eminent breeder . If gifted with these qualities , and he studies his subject for years , and devotes his lifetime to it with indomitable perseverance , he will succeed , and may make great improvements ; if he wants any of ...
37 페이지
... become blended together by crossing , may plainly be recognised in the increased size and beauty which we now see in the varieties of the heartsease , rose , pelargonium , dahlia , and other plants , when compared with the older ...
... become blended together by crossing , may plainly be recognised in the increased size and beauty which we now see in the varieties of the heartsease , rose , pelargonium , dahlia , and other plants , when compared with the older ...
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adapted affinities allied species America analogous ancient animals become bees believe birds breeds cause cells chapter characters cirripedes climate closely allied colour continuous crossed crustaceans degree difficulty distinct species divergence domestic doubt embryo Europe existing exterminated extinct extremely facts favourable Fcap fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period greater number groups of species habits Hence hermaphrodites History hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing intermediate land larvæ less living male mammals manner migration modification modified descendants natural selection naturalists nearly nest offspring perfect pigeons plants pollen Portrait Post 8vo present principle probably produced progenitor racter ranked reciprocal crosses remarked resemble rudimentary organs Second Edition seeds sexual selection Silurian slight South America sterility structure struggle successive supposed theory Third Edition tion variability variations varieties vary Vols widely Woodcuts