Fare you well, dinos!
A biological crisis, or mass extinction, occurs when at least 75% of the Earth's species disappear within a short period of time—that is, within a few hundreds of thousands of years. Both marine and terrestrial organisms are affected, and the crisis is global. You will find hereafter an account of the 5th extinction.
Sixty-six million years ago, two events combined to trigger a major biological crisis, leading to the extinction of the dinosaurs and many other life forms. This episode is known as the Great Cretaceous Extinction. The first event was the impact of a fifteen-kilometer-diameter meteorite on Mexico's Yucatan Peninsula. It sparked global fires and plunged the planet into prolonged darkness. Meanwhile, massive volcanism in the Deccan Traps of India exacerbated the situation by further cooling the climate and increasing ocean acidity. These upheavals made the environment particularly hostile to many species.
Non-avian dinosaurs, which had dominated the Earth for 160 million years, failed to adapt and disappeared within a few thousands of years. Other groups, such as reptiles and mammals, gradually filled the vacant ecological niches. These smaller, less specialized species survived thanks to their ability to adapt to a wide variety of habitats and diets.
The descendants of some dinosaurs have survived and continue to thrive to this day: find out which ones on panel 6.
Did you know?
Since the appearance of life, it is estimated that between 600 million and 2 billion species have lived on Earth. 95% have become extinct and only 0.02 to 0.07% have been described, with 400,000 fossil species identified.
Informations complémentaires
Five major extinctions have disrupted life on Earth. To discover their stories, step through the gates along the Time Trail.
