Situation: If humans descended from monkeys, why are there still monkeys? This surprisingly common argument relects several levels of ignorance about evolution. The first mistake is that evolution does not teach that humans descended from monkeys; it states that both have a common ancestor. The deepe error is that this objection is tantamount to asking, "If children descended from adults, why are there still adults?" New species evolve by splintering off from established ones, when populations of organisms become isolated from the main branch of their family and acquire sufficient difference to remain forever distinct. The parent species may survive indefinitely thereafter, or may become extinct.