The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432페이지 |
도서 본문에서
54개의 결과 중 1 - 5개
vii 페이지
... Fertility of varieties when crossed , and of their mongrel offspring not universal - Hybrids and mongrels compared independently of their fertility - Summary 219 b CHAPTER X. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD . CONTENTS . vii.
... Fertility of varieties when crossed , and of their mongrel offspring not universal - Hybrids and mongrels compared independently of their fertility - Summary 219 b CHAPTER X. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD . CONTENTS . vii.
xii 페이지
... fertile hybrid moths . The discussion on the fertility of hybrids ' not having been acquired through natural selection condensed and modified . On the causes of sterility of hybrids , added to and corrected . Pyrgoma found in the chalk ...
... fertile hybrid moths . The discussion on the fertility of hybrids ' not having been acquired through natural selection condensed and modified . On the causes of sterility of hybrids , added to and corrected . Pyrgoma found in the chalk ...
3 페이지
... fertility of varieties when intercrossed ; and fourthly , the imperfection of the Geological Record . In the next chapter I shall consider the geological succession of organic beings throughout time ;. INTRODUCTION . 3 CHAPTER I ...
... fertility of varieties when intercrossed ; and fourthly , the imperfection of the Geological Record . In the next chapter I shall consider the geological succession of organic beings throughout time ;. INTRODUCTION . 3 CHAPTER I ...
7 페이지
... fertile eggs . Many exotic plants have pollen utterly worthless , in the same condition as in the most sterile hybrids . When , on the one hand , we see domesticated animals and plants , though often weak and sickly , breeding freely ...
... fertile eggs . Many exotic plants have pollen utterly worthless , in the same condition as in the most sterile hybrids . When , on the one hand , we see domesticated animals and plants , though often weak and sickly , breeding freely ...
11 페이지
... fertility of varieties when crossed , - a subject hereafter to be discussed ) , domestic races of the same . species differ from each other in the same manner as do the closely- allied species of the same genus in a state of nature ...
... fertility of varieties when crossed , - a subject hereafter to be discussed ) , domestic races of the same . species differ from each other in the same manner as do the closely- allied species of the same genus in a state of nature ...
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accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young