The most infectious microorganisms are studied in a biosafety level four lab. The safety precautions taken by scientists who study viruses like Ebola must be extreme and constant to match the level of danger posed by these pathogens. #Breakthrough is now streaming on Disney . | National Geographic Science

All 50 episodes of the *NEW* Crash Course Biology series are now available on YouTube! 🎊 Take a journey through life’s vast interconnectedness and discover how evolution, genetics, ecology, and cell and organismal biology deepen our knowledge of every living thing: including YOU! https://www.youtube.com/playlist?list=PL8dPuuaLjXtPW_ofbxdHNciuLoTRLPMgB | CrashCourse

19 reactions | 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 | Facebook