The Cambrian Period

The Cambrian Period, which occurred approximately 541 to 485 million years ago, was a significant time in Earth's history. It is known for the rapid diversification of life forms, often referred to as the "Cambrian explosion."

Key Points to Remember

The Cambrian Period marked the beginning of the Paleozoic Era.
It is often considered the period when most major groups of animals first appeared in the fossil record.
The Cambrian explosion refers to the rapid appearance and diversification of multicellular organisms.
During this period, life was primarily aquatic, with marine environments teeming with diverse marine invertebrates.
Trilobites, brachiopods, and early chordates were among the dominant life forms of the Cambrian seas.

Study Guide

1. What are the defining characteristics of the Cambrian Period?

The Cambrian Period is characterized by the rapid diversification of life forms, known as the Cambrian explosion. It was a time when most major groups of animals first appeared in the fossil record.

2. What types of environments were predominant during the Cambrian Period?

During the Cambrian Period, marine environments were predominant, and they were teeming with diverse marine invertebrates.

3. Can you name some of the dominant life forms of the Cambrian seas?

The dominant life forms of the Cambrian seas included trilobites, brachiopods, and early chordates.

4. How is the Cambrian explosion significant in the history of life on Earth?

The Cambrian explosion represents a pivotal time in the history of life on Earth, as it marked the emergence of a wide variety of multicellular organisms, laying the foundation for the subsequent evolution of complex life forms.