ABSTRACT
Cain slew Abel (Gen. 4:8) for reasons of petty jealousy: siblicide. Later God ordered Abraham to sacrifice his son Isaac as a test of faith (Gen. 22:2): infanticide. These biblical legends gained a measure of ecological complexity when the twin sons of Isaac and Rebekah battled in utero for the all-important first position: brawny Esau won the battle but lost the war (and his birthright) when the astute Jacob caught him short of critical resources (food) and struck a hard bargain.
