Portal was the first Valve-developed game to be added to the OS X-compatible list of games available on the launch of the Steam client for Mac on May 12, 2010, supporting Steam Play, in which players that had bought the game either on a Macintosh or Windows computer could also play it on the alternate system.
1 Eurasian Pleistocene megafauna became extinct in roughly same time period despite having a much longer time to adapt to hunting pressure by humans. 2  However, the extinction of the Eurasian megafauna can be viewed as a result of a different process than that of the American megafauna.
Natural Causes of Extinction. Climatic Heating and Cooling. Climate Change is caused by a number of things. The effect that climate has on extinction is very big. The biodiverse Earth can't keep up with the rapid changes in temperature and climate.