What were common life forms during the Cambrian period?

The Cambrian period, which occurred approximately 541 million to 485.4 million years ago, marked a significant point in the history of life on Earth known as the Cambrian Explosion. During this time, there was a rapid diversification of life, particularly in the oceans, where most Cambrian organisms lived.

Common life forms during the Cambrian period include:

1. Trilobites - One of the most diverse and abundant groups, they were marine arthropods with exoskeletons and are often found as fossils. 2. Anomalocaris - A large predatory arthropod that swam in the Cambrian seas, known for its unusual body plan with large eyes and grasping appendages to capture prey. 3. Brachiopods - Shelled organisms that resembled clams but were quite different in structure and anatomy. They anchored themselves to the sea floor. 4. Sponges - Simple multicellular organisms, they were some of the earliest forms of animal life and were filter feeders. 5. Echinoderms - A group that includes modern starfish and sea urchins; in the Cambrian, they had many different forms, some of which were quite bizarre compared to today’s species. 6. Early mollusks - Including organisms similar to modern-day snails, clams, and cephalopods (like squid and octopuses). 7. Small shelly fauna - An assortment of tiny, shelled organisms that appeared in the early Cambrian. Their evolutionary relationships are often hard to determine. 8. Priapulid worms - Marine worms that lived in burrows and are known from their well-preserved fossils. 9. Algae - Simple photosynthetic organisms that were common in Cambrian seas and formed an important basis for the food chain.

The Cambrian period saw life forms that could burrow, swim, and in some cases, even prey on one another, indicating the presence of complex ecosystems and predator-prey relationships. The Cambrian Explosion is one of the most significant evolutionary events as it set the stage for the diversity of life we see on Earth today.