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 7
... never seed ! In some few cases it has been discovered that a very trifling change , such as a little more or less water at some particular period of growth , will determine whether or not a plant will produce seeds . I cannot here give ...
... never seed ! In some few cases it has been discovered that a very trifling change , such as a little more or less water at some particular period of growth , will determine whether or not a plant will produce seeds . I cannot here give ...
Página 18
... never heard of an instance in England ; and the mongrels were black , brown , and mottled . I also crossed a barb with a spot , which is a white bird with a rod tail and red spot on the forehead , and which 18 CHAP . L Domestic Pigeons .
... never heard of an instance in England ; and the mongrels were black , brown , and mottled . I also crossed a barb with a spot , which is a white bird with a rod tail and red spot on the forehead , and which 18 CHAP . L Domestic Pigeons .
Página 20
... never less than 20,000 pigeons were taken with the court . " The monarchs of Iran and Turan sent him some very rare birds ; " and , continues the courtly historian , “ His Majesty by crossing the breeds , which method was never ...
... never less than 20,000 pigeons were taken with the court . " The monarchs of Iran and Turan sent him some very rare birds ; " and , continues the courtly historian , “ His Majesty by crossing the breeds , which method was never ...
Página 21
... never met a pigeon , or poultry , or duck , or rabbit fancier , who was not fully convinced that each main breed was descended from a dis- tinct species . Van Mons , in his treatise on pears and apples , shows how utterly he disbelieves ...
... never met a pigeon , or poultry , or duck , or rabbit fancier , who was not fully convinced that each main breed was descended from a dis- tinct species . Van Mons , in his treatise on pears and apples , shows how utterly he disbelieves ...
Página 22
... never desire to sit , and with the bantam so small and elegant ; when we compare the host of agricultural , culinary , orchard , and flower - garden races of plants , most useful to man at different seasons and for different purposes ...
... never desire to sit , and with the bantam so small and elegant ; when we compare the host of agricultural , culinary , orchard , and flower - garden races of plants , most useful to man at different seasons and for different purposes ...
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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