The beginning of our wold started in what we call the Hadean Eon. The solar system was just starting to form, and all of the planets were molten rock, including Earth. Next came the Archean Eon. Most of the molten rock had now cooled to a solid. The atmosphere was full of toxic gases, like methane and ammonia. This was caused by the high amounts of volcanic activity. The Proterozoic Eon marked a drastic change in Earth's climate. The molten rock and boiling magma was replaced by ice. Life started forming, including red and green algae. These plants helped to raise the oxygen levels on our planet. Now we've come to the Phanerozoic Eon. This began 542 million years ago, and has continued down to this day. It started off with the Cambrian period. During this time, the earth was full of brachiopods, trilobites, and hyolithids. The climate was mild. Life started seeing more diversity going into the Ordovician period. Most of Earth was covered in ocean. We started seeing primitive fish, corals, gastropods, snails, clams, and plant spores. The climate started off warm, then got cold, leading to an extinction. Now we've come to the Silurian period. And no, we're not talking about the lizard people from Doctor Who. At this time, the climate became more stable, which led to an increase in early plant life. More fish started appearing, along with fungi, arachnids, and centipedes on land. These plants continued growing into the Devonian period, introducing us to ferns. During this time, a drastic change in fish life occurred. Arachnids still lived on land, as well as some wingless insects. Now we've come to the Carboniferous period. The earth was now dominated by large swamps, which have provided us with most of our coal today. The climate was more humid and tropical than it is today. More modern fish started appearing, as well as huge amphibians. Early conifers started growing, and we saw the introduction of dragonflies, mayflies, millipedes, scorpions, and spiders. After this came the Permian, and with that a mass extinction. Many of the ferns changed to conifers. Now comes the dawn of the dinosaurs. Triassic period kicked it all of with life outside of the ocean beginning to diversify. Next came the well-known Jurassic period, with giant herbivores, small and vicious carnivores, and the earliest, small mammals. We also saw more life take to the sky, with pterosaurs and the first birds. Next came with the Cretaceous, and with it the first flowers. Ants and butterflies soon followed the flowers, along with aphids, grasshoppers, wasps and termites. Then came another mass extinction. Now we've arrived at the Paleogene period. Small mammals were alive, along with the first elephants with trunks, early horses, deer, camels, cats, dogs, and primates. Grass started growing, which gave rodents a place to hide. With rodents came the first falcons, eagles, and hawks. The grass kept growing into the Neogene period, with much grassland and savanna. Many of the plants we see today we seen in this period as well. Kelp forest started to grow, and with those came sea otters and similar mammals. The last stop is the Quaternary period. The beginning of this period was marked with what many know as the Ice Age. Mammoths, mastodons, saber-toothed cats, and giant ground sloths ruled the earth. After they died off, we came along, to take this planet for ourselves.

• published: 18 Apr 2015
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