On the Origin of the Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeJohn Murray, 1869 - 596 páginas |
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear archipelago Asa Gray become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common continuous crossed crustaceans degree developed difficulty distinct species divergence doubt eggs embryo existing exterminated extinct extremely facts favourable females fertilised fertility flowers formation forms fossil Fritz Müller Gärtner genera genus geological Glacial period gradations greater number groups of species habits Hence hermaphrodites hive-bee hybrids important individuals inhabitants inherited insects instance instincts intercrossing larvæ less living males mammals manner migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation parent perfect pigeons pistil pollen present principle probably produced progenitor racters ranked reciprocal crosses remarked resemble rudimentary organs seeds sexual sexual selection Silurian slight South America stamens sterility structure struggle successive suppose theory tion variability variations vary whilst whole