Paleozoic Era

The Paleozoic Era, which means "ancient life," is a geologic era that lasted from about 541 to 252 million years ago. It is known as the era of the first complex life forms, including the first fish, plants, and insects. The Paleozoic Era is divided into six periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian.

Key Events and Characteristics

• Cambrian Period: The Cambrian Explosion occurred during this period, marking the rapid diversification of multicellular life forms, including the appearance of many major animal groups.
• Ordovician Period: The first land plants and diverse marine invertebrates emerged during this period. It was also a time of extensive glaciation.
• Silurian Period: The first vascular plants and terrestrial arthropods appeared, and the colonization of land by plants and animals continued.
• Devonian Period: Often referred to as the "Age of Fishes," this period saw the diversification of fish and the first forests dominated by vascular plants.
• Carboniferous Period: This period is known for its vast swamp forests, which eventually formed the coal deposits that are mined today. Reptiles and insects also became widespread.
• Permian Period: The Permian ended with the largest mass extinction in Earth's history, known as the Permian-Triassic extinction event. It led to the disappearance of over 95% of marine species and marks the end of the Paleozoic Era.

Study Guide

1. What is the Paleozoic Era, and when did it occur?
2. List the six periods of the Paleozoic Era and provide a key characteristic or event for each.
3. Describe the significance of the Cambrian Explosion.
4. Explain the major developments in plant and animal life during the Paleozoic Era.
5. Discuss the causes and consequences of the Permian-Triassic extinction event.

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