The Paleozoic era is defined by the proliferation and diversification of a wide range of complex life forms, especially marine organisms. It is known as the "Age of Invertebrates" because of the dominance and diversification of invertebrates such as trilobites, brachiopods, and mollusks. Another defining characteristic of the Paleozoic era is the appearance and subsequent diversification of early land plants and the establishment of terrestrial ecosystems. Additionally, the Paleozoic era is marked by multiple major geological and climatic events, including the formation and break-up of supercontinents, significant climate changes, and mass extinctions.
