On the Origin of Species By Means of Natural Selection, Or, the Preservation of Favoured Races in the Struggle for Life
On the Origin of Species By Means of Natural Selection, Or, the Preservation of Favoured Races in the Struggle for Life
Darwin, Charles, 1809-1882
The book On the Origin of Species By Means of Natural Selection, Or, the Preservation of Favoured Races in the Struggle for Life was written by author Darwin, Charles, 1809-1882 Here you can read free online of On the Origin of Species By Means of Natural Selection, Or, the Preservation of Favoured Races in the Struggle for Life book, rate and share your impressions in comments. If you don't know what to write, just answer the question: Why is On the Origin of Species By Means of Natural Selection, Or, the Preservation of Favoured Races in the Struggle for Life a good or bad book?
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Kolreuter, whose accuracy has been confirmed by every subsequentobserver, has proved the remarkable fact, that one variety of thecommon tobacco is more fertile, when crossed with a widely distinctspecies, than are the other varieties. He experimentised on fiveforms, which are commonly reputed to be varieties, and which he testedby the severest trial, namely, by reciprocal crosses, and he foundtheir mongrel offspring perfectly fertile. But one of these fivevarieties, when used either as father o...r mother, and crossed with theNicotiana glutinosa, always yielded hybrids not so sterile as thosewhich were produced from the four other varieties when crossed with N. Glutinosa. Hence the reproductive system of this one variety must havebeen in some manner and in some degree modified. From these facts; from the great difficulty of ascertaining theinfertility of varieties in a state of nature, for a supposed varietyif infertile in any degree would generally be ranked as species; fromman selecting only external characters in the production of the mostdistinct domestic varieties, and from not wishing or being able toproduce recondite and functional differences in the reproductivesystem; from these several considerations and facts, I do not thinkthat the very general fertility of varieties can be proved to be ofuniversal occurrence, or to form a fundamental distinction betweenvarieties and species.
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