The History of the Earth

By joelkumi
  • 4600 BCE

    The Formation of the Earth

    The earth was formed 4.6 billion years ago
  • Period: 4000 BCE to 2500 BCE

    Archean Eon

    The collision of the moon into Earth significantly impacted climate, oceans and life on Earth. Because the moon’s orbit drags Earth, it slowed Earth’s rotation significantly from 6 hour days to 24 hours. By having the moon in orbit, it also stabilized the Earth from wobbling. But most importantly, the collision of the moon tilted Earth on its axis. And because the Earth is tilted on its axis, Earth now had seasons.
  • Period: 2500 BCE to 541 BCE

    Proterozoic Eon

    Earth now had an oxygenated atmosphere for new life to flourish on Earth. But it wasn’t cyanobacteria flourishing. Because oxygen was toxic for cyanobacteria, they poisoned all anaerobic life on Earth including themselves. Imagine a dominant species polluting the planet until extinction. The oxygen byproduct from cyanobacteria created an oxygen crisis on Earth.
  • Period: 541 BCE to 245 BCE

    Paleozoic Era

    The Cambrian explosion was the largest diversification of life in Earth’s history. Everything before this era was precambrian. We couldn’t identify life because we didn’t have fossilized shells or animals. This is when hard-shelled invertebrates originated in the oceans. The Cambrian explosion started with the Age of Invertebrates. And life got more diverse from there.
  • Period: 245 BCE to 66 BCE

    Mesozoic Era

    When Earth’s climate became hotter and drier, rainforests collapsed triggering the Age of Reptiles. Reptiles are different from amphibians because they lay their hard-shelled eggs on land. They essentially adapted to the land by cutting all ties with the ocean. Because reptiles evolved to dryland conditions, they gained a unique ecological advantage.
  • Period: 66 BCE to 1 BCE

    Cenozoic Era

    Ultimately, the start of the Cenozoic Era was the demise of dinosaurs. After a 6-mile wide asteroid hit Earth, a dust cloud blocked the sun. This caused temperatures to plummet which was the heart of the damage from the Cretaceous–Paleogene extinction event. Because of the worldwide climate disruption, it was responsible for the extinction of the dinosaurs.