In which John Green teaches you about population. So, how many people can reasonably live on the Earth? Thomas Malthus got it totally wrong in the 19th century, but for some reason,... Read more »
Is the world overpopulated or underpopulated? While we worry about there being too many people for the planet to support, we can also worry about how fewer people in a given place... Read more »
Hank guides us through the process of natural selection, the key mechanism of evolution. Crash Course Biology is now available on DVD! http://dftba.com/product/1av/CrashCourse-Biology-The-Complete-Series-DVD-Set Like CrashCourse on Facebook: http://www.facebook.com/YouTubeCrashCourse Follow CrashCourse on Twitter:... Read more »