f1a32aee_Evolutionary_physiology__Event
[Date] 4500 Ma [Event] 
According to one plausible theory, the planet Earth and the planet Theia collide, sending a very large number of moonlets into orbit around the young Earth. These moonlets eventually coalesce to form theMoon.The gravitational pull of the new Moon stabilises the Earth's fluctuating axis of rotation and sets up the conditions in which life formed.
Evolutionary physiology
Event