Description
Excerpt from The Origin of Species, Vol. 2 of 2: By Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life
It is certain, on the one hand, that the sterility of various species when crossed is so different in degree and graduates away so insensibly, and, on the other hand, that the fertility of pure species is so easily affected by various circumstances, that for all prae tical purposes it is most difficult to say where perfect fertility ends and ''sterility begins. I think no better evidence of this can be re quired than that the two most experienced observers who have ever lived, namely, Kolreuter and Gartner, arrived at diametrically Opposite conclusions in regard to some of the very same forms. It is also most instructive to compare - but I have not space here to enter on details - the evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties, with the evidence from fertility adduced by different hybridizers, or by the same observer from experiments made during different years. It can thus be shown that neither sterility nor fertility affords any certain distinction between species and varieties. The evidence from this source graduates away, and is doubtful in the same degree as is the evidence derived from other constitutional and structural differences.
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This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
It is certain, on the one hand, that the sterility of various species when crossed is so different in degree and graduates away so insensibly, and, on the other hand, that the fertility of pure species is so easily affected by various circumstances, that for all prae tical purposes it is most difficult to say where perfect fertility ends and ''sterility begins. I think no better evidence of this can be re quired than that the two most experienced observers who have ever lived, namely, Kolreuter and Gartner, arrived at diametrically Opposite conclusions in regard to some of the very same forms. It is also most instructive to compare - but I have not space here to enter on details - the evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties, with the evidence from fertility adduced by different hybridizers, or by the same observer from experiments made during different years. It can thus be shown that neither sterility nor fertility affords any certain distinction between species and varieties. The evidence from this source graduates away, and is doubtful in the same degree as is the evidence derived from other constitutional and structural differences.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Details
Publisher - Forgotten Books
Language - English
Hardback
Contributors
Author
Charles Darwin
Published Date -
ISBN - 9781528288583
Dimensions - 22.9 x 15.2 x 1.3 cm
Page Count - 237
Paperback
Contributors
Author
Charles Darwin
Published Date -
ISBN - 9781330018934
Dimensions - 22.9 x 15.2 x 1.3 cm
Page Count - 239
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