the origin of species · darwin
Charles Darwin's Origin of 1859 argues, from breeding, geology, geography and embryology, that species are not fixed but descend with modification from common ancestors by natural selection. The chapters read here lay out the theory, answer its difficulties, and end with the grandeur in a view of life that has no need of separate creations.
Charles Darwin, The Origin of Species (Signet Classics, 2003). Read in Junior Spring at Torrey Honors: the Introduction; chapters I to IV, VI and VII; from chapter VIII, Objections to the Theory of Natural Selection as Applied to Instincts, Neuter and Sterile Insects, and the Summary; and chapters IX and XV.