One of the most mysterious times in the history of Earth is that of the “Cambrian Explosion,” when in a short period of time (few millions of years) most of the animal ancestors of all animals alive today (including humans) suddenly appeared. Why did the “Cambrian Explosion” happen, knowing that before this event absolutely no other faunal explosions happened in billions of years of Earth’s history? It is too mysterious that all happened right at the Cambrian, and, further, if not for this event no animal we are familiar with today would exist.  Watch the video posted in our week 5 module (youtube video’s URL link: