Mechanisms of Evolution GENETIC DRIFT & NATURAL SELECTION Five Factors Drive Evolution Mutation Venom-like proteins first appeared about 200 million years ago Venoms evolved from other proteins Venoms were recruited from other functions I. Natural Selection Green mamba is arboreal Its venom is most effective against birds. Black mamba is terrestrial Its venom is most effective against mammals. OVERPRODUCTION HERITABLE VARIABILITY COMPETITION DIFFERENTIAL REPRODUCTION II. GENETIC DRIFT The smaller the population, the less genetic variety it has. In a very small population, alleles can be lost from one generation to the next, simply by random chance. When a population evolves only because of this type of random sampling error, GENETIC DRIFT is taking place. FOUNDER EFFECT BOTTLENECK EFFECT AND IN 4.5 BILLION YEARS… The diversity of life on earth around us evolved.