Cambrian is a period of time in Earth’s history when there was a rapid diversification of life. It lasted from about 541 to 485 million years ago, and was the first period in the Paleozoic era. The Cambrian is named after the Latin word for Wales, where rocks from this period were first studied.
During the Cambrian, almost all major animal groups appeared for the first time. This includes vertebrates, mollusks, arthropods, and echinoderms. Many of these groups would go on to become dominant during later periods. For example, fish became common in the oceans during the Cambrian, and would eventually give rise to amphibians, reptiles, and mammals on land. Arthropods such as insects and spiders would also become very successful during later periods.
The Cambrian was a time of great change for life on Earth. It saw the rise of many new animal groups, and the spread of animals to new environments. The diversification of life during this period laid the foundation for all subsequent biodiversity on our planet.