The Columbian Exchange has left us with not a richer, but a more impoverished genetic pool, and we, all of life on the planet, are the less for Columbus, and the impoverishment will increase. But let's give you the last word today. Do you agree with Crosby? Are longer, healthier lives for more humans worth the sacrifice of an impoverished biosphere? And most importantly, how will your conclusions about those questions shape the way that you live your life? Thanks for watching, I'll see you next week. Crash Course is produced and directed by Stan Miller.