Dinosaur bones were first discovered in 1677 by an Englishman named Robert Plot. However, William Buckland, born on March 12, 1784, was the first person to identify what dinosaur bones were. Before dinosaurs, there were once living creatures that inhabited the Earth. Those were called microscopic organisms or microbes for short. Microbes existed about 3.5 billion years ago whereas dinosaurs are estimated to have been alive around 233-243 million years ago.

Why are dinosaurs not still here today if they were once alive creatures? About 66 million years ago, an asteroid crashed into Earth, exploded, and caused a massive crater in Mexico, StarDate explains. Because of the big climate change, there were more volcanic eruptions, which also caused more dinosaurs to die.

The only survivors of the asteroid were birds, frogs, and salamanders. After the asteroid hit Earth and wiped out the dinosaurs, plants began to dominate the Earth. Also, marine life began to flourish during this time.

Therefore, around 1.7 million years ago, marine life restored itself, but it took at least 30,000 years for life on this planet to go back. Now, how did this affect mammals? 100,000 years after the asteroid hit the land, mammals have doubled and were around raccoon sized, says Elizabeth Pennisi from Science.org. With dinosaurs gone, mammals were able to begin dominating the Earth.

Throughout the course of history’s major mass extinction cases, this one would be one of the biggest. With the dinosaurs long gone leaving only mammals, birds, fish, reptiles and amphibians, mammals have become the most notable dominant species on Earth. If the asteroid did not hit Earth, would mammals still have dominated today? What would have happened to the dinosaurs now?