On the Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for Life

adapted affinities allied species America amount analogous ancient animals become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence domestic doubt embryo Europe existing exterminated extinct extremely facts favourable Fcap fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites History hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing intermediate land larvæ less living male mammals manner migration modification modified descendants natural selection naturalists nearly nest offspring perfect pigeons plants pollen Post 8vo present principle probably produced progenitor racters ranked reciprocal crosses remarked resemble Second Edition seeds sexual selection Silurian slight South America sterility structure struggle successive suppose theory Third Edition tion variability variation varieties vary Vols whole widely Woodcuts