Extinction

E X T I N C T I O N

The Cretaceous–Paleogene (K–Pg) extinction event,formerly known as theCretaceous–Tertiary (K–T) extinction,[b] was a mass extinction of some three-quarters of plant and animal species on Earth—including all non-avian dinosaurs—that occurred over a geologically short period of time 66 million years ago. It marked the end of theCretaceous period and with it, the entire Mesozoic Era, opening the Cenozoic Era which continues today.

As originally proposed by a team of scientists led by Luis Alvarez, it is now generally believed that the K–Pg extinction was triggered by a massive comet/asteroid impact and its catastrophic effects on the global environment, including a lingering impact winter that made it impossible for plants and plankton to carry out photosynthesis.[4][5] The impact hypothesis was bolstered by the discovery of the 180-kilometre-wide (112 mi) Chicxulub crater in the Gulf of Mexico in the early 1990s.

Death by asteroid