Final answer:
During the Cretaceous Period, over 96% of marine species and 70% of terrestrial species went extinct.
Step-by-step explanation:
The Cretaceous Period, a geologic era that lasted from approximately 145 to 66 million years ago, witnessed a significant event known as the Cretaceous-Paleogene (K-Pg) mass extinction. This mass extinction had a profound impact on life on Earth, leading to the disappearance of a vast number of species.
The extinction event is widely attributed to the impact of a large asteroid or comet, which caused massive environmental disturbances, including wildfires, tsunamis, and a "nuclear winter" effect from debris in the atmosphere.
The extinction rate during the Cretaceous Period was exceptionally high, with estimates suggesting that over 96% of marine species and 70% of terrestrial species became extinct. This catastrophic event reshaped the Earth's ecosystems and paved the way for the rise of new species during the subsequent Cenozoic Era. The profound changes in biodiversity and ecological dynamics had long-lasting effects on the evolutionary trajectory of life on our planet.
Understanding past extinction events is crucial for scientists to unravel the complex interplay of factors that shape the history of life on Earth. The Cretaceous-Paleogene mass extinction, marked by the disappearance of iconic species like the dinosaurs, serves as a key reference point in the study of Earth's geological and biological evolution.