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 XIX - SUMMARY OF THE FOUR LAST CHAPTERS, WITH REMARKS ON HYBRIDISM
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
It was shown in the fifteenth chapter that when individuals of the same variety, or even of a distinct variety, are allowed freely to intercross, uniformity of character is ultimately acquired. Some few characters, however, are incapable of fusion, but these are unimportant, as they are almost always of a semi-monstrous nature, and have suddenly appeared. Hence, to preserve our domesticated breeds true, or to improve them by methodical selection, it is obviously necessary that they should be kept separate. Nevertheless, through unconscious selection, a whole body of individuals may be slowly modified, as we shall see in a future chapter, without separating them into distinct lots. Domestic races have often been intentionally modified by one or two crosses, made with some allied race, and occasionally even by repeated crosses with very distinct races; but in almost all such cases, long-continued and careful selection has been absolutely necessary, owing to the excessive variability of the crossed offspring, due to the principle of reversion. In a few instances, however, mongrels have retained a uniform character from their first production.
When two varieties are allowed to cross freely, and one is much more numerous than the other, the former will ultimately absorb the latter.
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- The Variation of Animals and Plants under Domestication , pp. 173 - 191Publisher: Cambridge University PressPrint publication year: 2010First published in: 1868