jan 1, 65000000 BC - Mass Extinction
Description:
That one...Many planktonic organisms and bottom-dwelling invertebrates went extinct. Most animals larger than about 25 kg in body weight also went extinct.
This would give rise to the radiation mammals and many of the organisms directly related to those seen today.
Added to timeline:
Date:
jan 1, 65000000 BC
Now
~ 5883516 years ago