On the Origin of Species by Means of Natural Selection: Or The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1888 - 458 páginas |
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Página vii
... Fertility of varieties when crossed and of their mongrel offspring not universal — Hybrids and mongrels compared independently of their tertility Summary - - 234-263 CHAPTER X. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD . CONTENTS . vil.
... Fertility of varieties when crossed and of their mongrel offspring not universal — Hybrids and mongrels compared independently of their tertility Summary - - 234-263 CHAPTER X. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD . CONTENTS . vil.
Página xii
... fertile hybrid moths . The discussion on the fertility of hybrids not having been ac- quired 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 ac- quired through natural selection condensed and modified . On the causes of sterility of hybrids , added to and corrected . Pyrgoma found in the chalk ...
Página 4
... fertility of varieties when intercrossed ; and fourthly , the imperfection of the Geological Record . In the next chapter I shall consider the geo- logical succession of organic beings throughout time ; in the twelfth and thirteenth ...
... fertility of varieties when intercrossed ; and fourthly , the imperfection of the Geological Record . In the next chapter I shall consider the geo- logical succession of organic beings throughout time ; in the twelfth and thirteenth ...
Página 7
... 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 ...
Página 12
... 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 , but ...
... 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 , but ...
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Términos y frases comunes
adapted admit affinities allied species America analogous ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important 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 reproductive resemblance rudimentary seeds sexual selection slight South America stamens sterility structure struggle successive supposed tend theory tion variability variations varieties vary whilst whole wings young