Skip links

Facts about the Paleozoic Era for Kids


  • The Paleozoic is the earliest of three geologic eras of the Phanerozoic Eon, spanning from roughly 541 to 252.2 million years ago (ICS, 2004).
  • The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon, and is followed by the Mesozoic Era.
  • The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth’s history, known as the Cambrian explosion, in which most modern phyla first appeared.
  • Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms.
  • Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America.
  • Towards the end of the era, large, sophisticated reptiles were dominant and the first modern plants (conifers) appeared.
  • The Paleozoic Era ended with the largest mass extinction in Earth’s history, the Permian–Triassic extinction event.
  • The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic to recover.
  • In North America, the era began with deep sedimentary basins along the eastern, southeastern, and western sides of the continent, while the interior was dry land.
  • Beginning in the Ordovician Period, mountain building intermittently proceeded in the eastern part of the Appalachian region throughout the rest of the era, bringing in new sediments.
  • The Ordovician and Silurian periods were warm greenhouse periods, with the highest sea levels of the Paleozoic (200 m above today’s); the warm climate was interrupted only by a 30 million years cool period, the Early Palaeozoic Icehouse, culminating in the Hirnantian glaciation.
  • However, as if to offset this trend, Gondwana moved south with considerable speed, so that, in Ordovician time, most of West Gondwana (Africa and South America) lay directly over the South Pole.
  • Sea levels had dropped coincident with the ice age, but slowly recovered over the course of the Silurian and Devonian.
  • As plants took hold on the continental margins, oxygen levels increased and carbon dioxide dropped, although much less dramatically.
  • The Devonian ended with a series of turnover pulses which killed off much of Middle Paleozoic vertebrate life, without noticeably reducing species diversity overall.
  • The Lopingian is associated with falling sea levels, increased carbon dioxide and general climatic deterioration, culminating in the devastation of the Permian extinction.