[pey-lee-uh-zoh-ik or, especially Brit., pal-ee-] 
Geology| 1. | noting or pertaining to an era occurring between 570 million and 230 million years ago, characterized by the advent of fish, insects, and reptiles. |
| 2. | the Paleozoic Era or group of systems. |
| Pa·le·o·zo·ic (pā'lē-ə-zō'ĭk) adj. Of, belonging to, or designating the era of geologic time that includes the Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, and Permian periods and is characterized by the appearance of marine invertebrates, primitive fishes, land plants, and primitive reptiles. See Table at geologic time. n. The Paleozoic Era. |
| Paleozoic (pā'lē-ə-zō'ĭk) Pronunciation Key
The era of geologic time from about 540 to 245 million years ago. The beginning of the Paleozoic Era is characterized by a great diversity of marine invertebrate animals. Primitive fish and reptiles, land plants, and insects also first appeared during this time. The end of the Paleozoic is marked by the largest recorded mass extinction in the Earth's history, which wiped out nearly 90% of known marine life forms. See Chart at geologic time. |
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