Genetic drift happens when chance events cause alleles to spike or decline from one generation to the next. Sometimes a segment of a population gets isolated and continues to grow and mutate on it's own. Sometimes populations change as a result of natural disasters or human intervention. https://youtu.be/mFvmY9JASO4 | CrashCourse

1.8K views · 169 reactions | Best of Crash Course: Our very first...