AP BIOLOGY

Detailed explanation-1: -The Cretaceous-Paleogene boundary-65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India.

Detailed explanation-2: -The first segment of the Cenozoic Era, from 65 million years ago until the present, has historically been called the Tertiary Period. The abbreviation for the boundary between the Cretaceous and Tertiary periods is the K-T boundary, where K is the abbreviation for the German form of the word Cretaceous.

Detailed explanation-3: -This extinction event marks a major boundary in Earth’s history, the K-T or Cretaceous-Tertiary boundary, and the end of the Mesozoic Era. The K-T extinctions were worldwide, affecting all the major continents and oceans. There are still arguments about just how short the event was.

Detailed explanation-4: -The disappearances included the last of the great dinosaurs. Paleontologists speculated and theorized for many years about what could have caused this “mass extinction, ” known, as the K-T event (Cretaceous-Tertiary Mass Extinction event).

Detailed explanation-5: -The event receives its name from the German word Kreide, meaning “chalk” (which references the chalky sediment of the Cretaceous Period), and the word Tertiary, which was traditionally used to describe the period of time spanning the Paleogene and Neogene periods.