An examination of the earth's crust shows that thin layers of iridium, an element which only occurs in asteroids, are found deposited in soil about every 26 million years. If this is the case, the next extinction period will occur in about 16 million years. It is believed that one such extinction period killed off much of the vegetation on Earth, and therefore killed off the dinosaurs. The first creatures like people appeared on Earth about three million years ago. Homo sapiens appeared about 500,000 years ago.
People are the first animal to dominate the earth because of intellect and cooperation.
People are bright and formed social units for teamwork. Humanity developed morality which allowed for even greater harmony. All progress made by humanity has been made because morality restrained our savage animal nature to allow cooperation. Paleontologists estimate the age of fossils using techniques such as carbon dating. It is known that life forms have the same percentage of the radioactive isotope known as carbon 14 which exists in the atmosphere.