English, Islam, monotheistic, religious
Human expansion, Hunting and increased poaching.
BOOM
Hope this helps :)
It destroyed the Russian economy, but freed many nations that were behind its Iron Curtain. But thanks to Vladimir Putin, the Russian economy is doing better than it has been in many years. Oh, it also "ended" the Cold War.
The angle of the Earth on its axis causing the sun to beam on the Northern and Southern Hemispheres differently.