Book contents
- Frontmatter
- Contents
- CHAPTER XII INHERITANCE
- CHAPTER XIII INHERITANCE continued – REVERSION OR ATAVISM
- CHAPTER XIV INHERITANCE continued – FIXEDNESS OF CHARACTER – PREPOTENCY – SEXUAL LIMITATION – CORRESPONDENCE OF AGE
- CHAPTER XV ON CROSSING
- CHAPTER XVI CAUSES WHICH INTERFERE WITH THE FREE CROSSING OF VARIETIES – INFLUENCE OF DOMESTICATION ON FERTILITY
- CHAPTER XVII ON THE GOOD EFFECTS OF CROSSING, AND ON THE EVIL EFFECTS OF CLOSE INTERBREEDING
- CHAPTER XVIII ON THE ADVANTAGES AND DISADVANTAGES OF CHANGED CONDITIONS OF LIFE: STERILITY FROM VARIOUS CAUSES
- CHAPTER XIX SUMMARY OF THE FOUR LAST CHAPTERS, WITH REMARKS ON HYBRIDISM
- CHAPTER XX SELECTION BY MAN
- CHAPTER XXI SELECTION–continued
- CHAPTER XXII CAUSES OF VARIABILITY
- CHAPTER XXIII DIRECT AND DEFINITE ACTION OF THE EXTERNAL CONDITIONS OF LIFE
- CHAPTER XXIV LAWS OF VARIATION – USE AND DISUSE, ETC
- CHAPTER XXV LAWS OF VARIATION, continued – CORRELATED VARIABILITY
- CHAPTER XXVI LAWS OF VARIATION, continued – SUMMARY
- CHAPTER XXVII PROVISIONAL HYPOTHESIS OF PANGENESIS
- CHAPTER XXVIII CONCLUDING REMARKS
- INDEX
CHAPTER XV - ON CROSSING
Published online by Cambridge University Press: 05 July 2011
- Frontmatter
- Contents
- CHAPTER XII INHERITANCE
- CHAPTER XIII INHERITANCE continued – REVERSION OR ATAVISM
- CHAPTER XIV INHERITANCE continued – FIXEDNESS OF CHARACTER – PREPOTENCY – SEXUAL LIMITATION – CORRESPONDENCE OF AGE
- CHAPTER XV ON CROSSING
- CHAPTER XVI CAUSES WHICH INTERFERE WITH THE FREE CROSSING OF VARIETIES – INFLUENCE OF DOMESTICATION ON FERTILITY
- CHAPTER XVII ON THE GOOD EFFECTS OF CROSSING, AND ON THE EVIL EFFECTS OF CLOSE INTERBREEDING
- CHAPTER XVIII ON THE ADVANTAGES AND DISADVANTAGES OF CHANGED CONDITIONS OF LIFE: STERILITY FROM VARIOUS CAUSES
- CHAPTER XIX SUMMARY OF THE FOUR LAST CHAPTERS, WITH REMARKS ON HYBRIDISM
- CHAPTER XX SELECTION BY MAN
- CHAPTER XXI SELECTION–continued
- CHAPTER XXII CAUSES OF VARIABILITY
- CHAPTER XXIII DIRECT AND DEFINITE ACTION OF THE EXTERNAL CONDITIONS OF LIFE
- CHAPTER XXIV LAWS OF VARIATION – USE AND DISUSE, ETC
- CHAPTER XXV LAWS OF VARIATION, continued – CORRELATED VARIABILITY
- CHAPTER XXVI LAWS OF VARIATION, continued – SUMMARY
- CHAPTER XXVII PROVISIONAL HYPOTHESIS OF PANGENESIS
- CHAPTER XXVIII CONCLUDING REMARKS
- INDEX
Summary
In the two previous chapters, when discussing reversion and prepotency, I was necessarily led to give many facts on crossing. In the present chapter I shall consider the part which crossing plays in two opposed directions,–firstly, in obliterating characters, and consequently in preventing the formation of new races; and secondly, in the modification of old races, or in the formation of new and intermediate races, by a combination of characters. I shall also show that certain characters are incapable of fusion.
The effects of free or uncontrolled breeding between the members of the same variety or of closely allied varieties are important; but are so obvious that they need not be discussed at much length. It is free intercrossing which chiefly gives uniformity, both under nature and under domestication, to the individuals of the same species or variety, when they live mingled together and are not exposed to any cause inducing excessive variability. The prevention of free crossing, and the intentional matching of individual animals, are the corner-stones of the breeder's art. No man in his senses would expect to improve or modify a breed in any particular manner, or keep an old breed true and distinct, unless he separated his animals. The killing of inferior animals in each generation comes to the same thing as their separation. In savage and semi-civilised countries, where the inhabitants have not the means of separating their animals, more than a single breed of the same species rarely or never exists.
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- The Variation of Animals and Plants under Domestication , pp. 85 - 99Publisher: Cambridge University PressPrint publication year: 2010First published in: 1868