Evolution is the change over time in the inherited traits of a species. It is based on the principle that individuals of a species that have the best adaptations related to the environment tend to reproduce more and the beneficial traits they have let them out-compete other that are less well adapted to their environment, whose genes eventually die out.
This question has a two part answer. The first part is that an asteroid hitting the earth and the second part is massive volcanoes erupting around the world.
