between Europe and Asia (dividing Eurasia): along the Turkish Straits, the Caucasus and the Urals (historically also north of the Caucasus, along the Kuma–Manych Depression or along the Don River) between Asia and Africa (dividing Afro-Eurasia into Africa and Eurasia): at the Isthmus of Suez.
Increased heating, increased evaporation
Fire is important because it cooked food, provided light and provided heat
Volcanic eruptions and/or earthquakes caused by the shifting of tectonic plates
