The smoking gun pointing to large extinctions

As any child can tell you, the Mesozoic Era ends with the extinction of the dinosaurs. Most geologists think the cause of that extinction was the impact of an enormous meteorite that hit the Yucatan Peninsula in Mexico. As the theory goes, the impact was so large it led to global changes in the composition of the atmosphere. Smoke and dust raised by the collision blocked the sun’s light for a time, making temperatures drop and plants die off. Many species of both plants and animals didn’t live through the crisis, as parts of the food web simply fell apart. As it happens, the dinos were one gro...