|4.6 to 4.0 billion years ago
|Named after Hades, the ancient Greek god of the underworld. This era is associated with the formation of the Earth and the establishment of its early oceans.
|4.0 to 2.5 billion years ago
|The Earth’s crust had begun to solidify, life first appeared, and the Earth’s atmosphere and oceans formed.
|2.5 billion to 541 million years ago
|Named for the Greek words for “earlier life”. This era was characterized by the buildup of oxygen in the atmosphere and the development of simple multicellular organisms.
|541 to 252 million years ago
|Derived from the Greek words for “ancient life”, the Paleozoic era was when life as we know it took off with an explosion of diversity.
|252 to 66 million years ago
|Known as the age of dinosaurs, it was during the Mesozoic era that reptiles and mammals began to evolve, and the supercontinent Pangea began to drift apart.
|66 million years ago to the present
|Known as the age of mammals, this era saw the rise of mammals and flowering plants, the formation of the Himalayas and Alps, and the evolution of humans.