Paleozoic

American  

[pey-lee-uh-zoh-ik, pal-ee-] / ˌpeɪ li əˈzoʊ ɪk, ˌpæl i- /

adjective

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.

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noun

1. the Paleozoic Era or group of systems.

Paleozoic Scientific  

/ pā′lē-ə-zō′ĭk /

1. 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.

2. See Chart at geologic time

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Other Word Forms

• post-Paleozoic
  adjective
• pre-Paleozoic
  adjective

Etymology

Origin of Paleozoic

1830–40; paleo- + -zoic < Greek zōïkós pertaining to animals; see zo-, -ic

Example Sentences

See Examples For:

Paleozoic

It can also help reconstruct the ecology of early Paleozoic oceans, when crinoids were among many early animal groups flourishing in reef ecosystems.

From Science Daily ● Aug. 21, 2026

The experiments revealed that Paleozoic animals could survive in lower oxygen conditions than many modern species.

From Science Daily ● Jul. 12, 2026

And the limestone caves of Richards Spur in Oklahoma contain some of the world’s most diverse and well-preserved fossils from the Paleozoic.

From Science Magazine ● Jan. 11, 2024

When the going got tough in the Paleozoic Era, trilobites rolled up.

From New York Times ● Dec. 19, 2023

Sometimes too you will see the term Phanerozoic used to describe the span encompassing the Cenozoic, Mesozoic, and Paleozoic eras.

From "A Short History of Nearly Everything" by Bill Bryson