On the Origin of Species by Means of Natural Selection |
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Page 6
... incidental on other differences - Causes of the sterility of first crosses and of hybrids -- Parallelism between the effects of changed conditions of life and cross ing - Fertility of varieties when crossed and of their 6 CONTENTS .
... incidental on other differences - Causes of the sterility of first crosses and of hybrids -- Parallelism between the effects of changed conditions of life and cross ing - Fertility of varieties when crossed and of their 6 CONTENTS .
Page 7
Charles Darwin. ing - Fertility of varieties when crossed and of their mongrel offspring not uni versal - Hybrids and mongrels compared independently of their fertility - Sum- mary , . 217 CHAPTER IX . ON THE IMPERFECTION OF THE ...
Charles Darwin. ing - Fertility of varieties when crossed and of their mongrel offspring not uni versal - Hybrids and mongrels compared independently of their fertility - Sum- mary , . 217 CHAPTER IX . ON THE IMPERFECTION OF THE ...
Page 12
... fertility of species and the fertility of varieties when inter- crossed ; and fourthly , the imperfection of the Geological Record . In the next chapter I shall consider the geolog ical succession of organic beings throughout time ; in ...
... fertility of species and the fertility of varieties when inter- crossed ; and fourthly , the imperfection of the Geological Record . In the next chapter I shall consider the geolog ical succession of organic beings throughout time ; in ...
Page 15
... fertile eggs . Many exotic plants have pollen utterly worthless , in the same exact condition as in the most sterile hybrids . When , on the one hand , we see domesticated animals and plants , though often weak and sickly , yet breeding ...
... fertile eggs . Many exotic plants have pollen utterly worthless , in the same exact condition as in the most sterile hybrids . When , on the one hand , we see domesticated animals and plants , though often weak and sickly , yet breeding ...
Page 21
... fertility of varieties when crossed , -a subject hereafter to be dis cussed ) , domestic races of the same species differ from each other in the same manner as , only in most cases in a esser degree than , do closely - allied species of ...
... fertility of varieties when crossed , -a subject hereafter to be dis cussed ) , domestic races of the same species differ from each other in the same manner as , only in most cases in a esser degree than , do closely - allied species of ...
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Common terms and phrases
accumulated adapted affinities allied species America amount ancient animals appear become bees believe birds breeds cause cells characters cirripedes climate closely allied colour continuous crossed crustaceans degree difficulty distinct species divergence domestic doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing intermediate land larvæ laws less living look male mammals manner migration modification modified descendants natural selection naturalists nearly nest offspring organic organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rudimentary seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation varieties vary whole widely