The Paleozoic era, also known as the "old life" era, is a major division of geological time that spans from around 541 to 252 million years ago. It is divided into six periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Paleozoic era is known for the diversification and evolution of life on Earth, including the emergence of complex land plants, insects, and vertebrates. Major events during this time include the Cambrian explosion, the colonization of land by plants and animals, and the mass extinction at the end of the Permian period. Paleozoic research involves studying the fossils, geology, and environmental changes of this era to better understand the evolutionary history of life on Earth.