Around 543 million years ago the Cambrian Explosion occurred, some say it may represent the most important evolutionary event in the history of life on Earth. The “Cambrian Explosion” refers to the rapid appearance of most major living animal body plans in the fossil record within 20 million years or less. This may seem to be a long period of time but is a relatively short in evolutionary history. This swift change in the fossil record appears to be inconsistent with the ideal of the slow process of evolution. Though, the fossil record has had rapid changes like this at other times, often following times of major extinction. The modern body plans we know of today is not what the major body plans looked like during the Cambrian Explosion.
