The Cambrian Period lasted for nearly 53 million years, from about 543 million years ago, until 490 million years ago. The continents were still forming, but were mostly barren rocks. The land had no plant or animal life on it yet. During the Cambrian Period, there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas. The most plentiful species during this period were trilobites. The species got its name from the three lobes in the hard skin. The trilobite was also one of the first animals to have eyesight. There were plenty of other species living during the Cambrian Period also. Molluscs, worms, sponges and echinoderms filled the Cambrian seas. The plants of the Cambrian were mostly simple, one-celled algae.The Cambrian period ended in a mass extinction. Advancing glaciers would have lowered the temperature of the shallow seas where so many species lived. Changes in the temperature and the amount of oxygen in the water would have meant the end for any species that could not adapt.
Rarely Fossilized
Did you know that there are very few fossils of lizards, insects and other land animals? Most of the fossils that have been discovered are of animals that lived in the sea.
Secret Author
Robert Chambers was a well-know literary and intellectual figure who is primarily remembered today as the author of ‘Vestiges of Natural History of Creation’ in 1844. This work caused a great sensation in Victorian Britain. However, Robert kept the fact that he had written the book a secret.