Palaeozoic The first (570–248 Ma) of the three eras of the Phanerozoic. The Cambrian, Ordovician, and Silurian Periods together form the Lower Palaeozoic sub-era; the Devonian, Carboniferous, and Permian the Upper Palaeozoic sub-era. During the Palaeozoic, two major orogenies occurred: the Caledonian during the Lower Palaeozoic, and the Variscan in late Palaeozoic times. The faunas of the Palaeozoic are noted for the presence of many invertebrate organisms, including trilobites (Trilobita), graptolites (Graptolithina), brachiopods (Brachiopoda), cephalopods (Cephalopoda), and corals. By the end of the era, amphibians and reptiles were major components of various communities and giant tree-ferns, horsetails, and cycads gave rise to extensive forests.

Palaeozoic (Paleozoic) The first of the 3 eras of the Phanerozoic, about 590–248 Ma ago. The Cambrian, Ordovician, and Silurian Periods together form the Lower Palaeozoic Sub-Era; the Devonian, Carboniferous, and Permian the Upper Palaeozoic Sub-Era. It was an era of great evolutionary change among plants, which began to invade the land at its beginning. By the end of the era, amphibians and reptiles were major components of various communities and giant treeferns, horsetails (Calamitaceae), and cycads (Cycadaceae) gave rise to extensive forests. The name is derived from palaeo- and the Greek zoe, meaning ‘life’.

Palaeozoic (Paleozoic) The first of the three eras of the Phanerozoic, about 542–251 Ma ago. The Cambrian, Ordovician, and Silurian Periods together form the Lower Palaeozoic Sub-Era; the Devonian, Carboniferous, and Permian the Upper Palaeozoic Sub-Era. The faunas of the Palaeozoic are noted for the presence of many invertebrate organisms including Trilobitomorpha, Graptolithina, Brachiopoda, Cephalopoda, and corals. By the end of the era, amphibians and reptiles were major components of various communities and giant tree-ferns, horsetails, and cycads gave rise to extensive forests.

Palaeozoic(Paleozoic) The first of the three eras of the Phanerozoic, about 570–248 Ma ago. The Cambrian, Ordovician, and Silurian Periods together form the Lower Palaeozoic Sub-Era; the Devonian, Carboniferous, and Permian the Upper Palaeozoic Sub-Era. It was an era of great evolutionary change among plants, which began to invade the land at its beginning. By the end of the era, amphibians and reptiles were major components of various communities and giant tree-ferns, horsetails (Calamitaceae), and cycads gave rise to extensive forests. The faunas of the Palaeozoic are noted for the presence of many invertebrate organisms including trilobites, graptolites, brachiopods, cephalopods, and corals. The name is derived from palaeo- and the Greek zoe, meaning ‘life’.

Palaeozoic The first era of Phanerozoic time. It follows the Precambrian and is subdivided into the Lower Palaeozoic, comprising the Cambrian, Ordovician, and Silurian periods, and the Upper Palaeozoic, comprising the Devonian, Carboniferous, and Permian periods, It extended from about 590 million years ago to about 248 million years ago, when it was succeeded by the Mesozoic era.