what are some of the animals that existed during the cambrian period
This period lasted about 53 million years and marked a dramatic burst of evolutionary changes in life on Earth, known as the Cambrian Explosion. Among the animals that evolved during this period were the chordates â animals with a dorsal nerve cord; hard-bodied brachiopods, which resembled clams; and arthropods â ancestors of spiders, insects and crustaceans.