On the Origin of Species by Means of Natural Selection, Or, The Preservation of Favoured Races in the Struggle for LifePhilosophical Library, 1951 - 426 páginas |
Contenido
VARIATION UNDER DOMESTICATION | 6 |
VARIATION UNDER NATURE | 38 |
STRUGGLE FOR EXISTENCE | 52 |
Derechos de autor | |
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Términos y frases comunes
accumulated adapted affinities allied species amount analogous ancient animals appear archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distant distinct species divergence domestic doubt eggs embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flower formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important increase in number individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner migration modification modified descendants natural selection naturalists nearly nest occasionally oceanic islands offspring perfect pigeons pistil plants pollen present probably produced progenitor ranked reciprocal crosses remarked resemblance seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder theory tion trees variability variations vary whole widely