How did the dinosaurs become extinct?

(Lansing State Journal, March 26, 1997)

Many theories exist as to why dinosaurs disappeared from Earth about 65 million years ago.

Some scientists believe dinosaurs died out due to the rapid evolution of flowering plants. The theory goes like this: Up until the flowering plants came along, the dinosaurs ate things like pine needles from evergreen trees. Then flowering plants appeared, replacing many of the pine trees. Dinosaurs did not have time to switch their diet to flowers and, as a result, died of starvation.

Another recent and popular theory is that a giant asteroid or meteorite, as wide as 6 miles across, struck the Earth. This collision would have produced an explosive force and damage similar to that of a nuclear war. Vast amounts of dust, debris and ash would have spread quickly around the planet, blocking out the sunlight reaching Earth's surface. Lack of sunlight is believed to have lasted for several months and to have caused temperatures to drop worldwide from 66 degrees Fahrenheit to about 14 degrees. Without sunlight to perform photosynthesis, many plants would have died, causing a domino-like effect on other organisms in the food chain, including the dinosaurs.

These are only two of the many theories that attempt to explain the mass extinction of the dinosaurs. Scientists do not know and may never know what caused their extinction, but they continue to search for evidence to solve this puzzle.

Back to MSU Science Theatre Home Page