The Cretaceous Period is the third and final period of the Mesozoic Era, spanning from approximately 145 to 66 million years ago. It is known for being the last period of the age of dinosaurs, as well as the time when flowering plants and modern groups of insects, birds, and mammals began to diversify.
During the Cretaceous, the world was dominated by a supercontinent called Gondwana in the south and Laurasia in the north. The climate was warm and the sea levels were high, leading to widespread shallow seas and the formation of chalk deposits in many parts of the world.
The Cretaceous was a time of significant evolution and diversification of life. Dinosaurs continued to dominate the land, with the rise of iconic species like Tyrannosaurus rex and Triceratops. In the oceans, marine reptiles such as mosasaurs and plesiosaurs thrived, and new groups of fish and invertebrates emerged. Additionally, the Cretaceous saw the rapid spread of flowering plants, which eventually led to the evolution of modern ecosystems.
The Cretaceous period ended with one of the most well-known mass extinctions in Earth's history, often referred to as the Cretaceous-Paleogene (K-Pg) extinction event. This event led to the extinction of the non-avian dinosaurs, as well as many other plant and animal species. The cause of this extinction is still a topic of scientific debate, but evidence suggests that a combination of factors, including a large asteroid impact and volcanic activity, may have played a role.