Evidence from locations across the globe
supports the idea that a large asteroid
struck Earth near the present-day Gulf of
Mexico at the end of the Cretaceous Period.
This animation shows the globe at the end
of the Cretaceous, when dinosaurs still
roamed among recently evolved flowering
Scientists theorize that huge amounts of
water and dust entered the atmosphere and
blocked sunlight for years, cutting the
energy supply of plants on land and in the
ocean. Without sunlight, the base of the
food chain was devastated. Over half of
the plant and animal groups that were living
during the Cretaceous Period were extinct
when the Tertiary Period began.