The Cambrian describes an era of geology that began about 540 million years ago and lasted between sixty and seventy million years. This epoch is characterized by the development of a great biodiversity, which scientists call the "Cambrian Explosion". The name of this epoch was coined in 1835 by the British geologist Adam Sedgwick and is derived from Cambria, the Latin name for Wales, which was in use at the time of the Roman Empire. In Wales, from the beginning of the 19th century, numerous geological discoveries were made on sedimentary rocks from the Cambrian. This era is today divided by scientists in four series and a total of ten levels, with many sections are not yet named.
The climatic conditions of the Cambrian were characterized by a worldwide mild to very hot weather with high humidity. After the glaciations of the previous Proterozoic, the continents were as free of ice as the poles. The continents were characterized on the one hand by huge dry desert areas, on the other hand, large-scale sea flooding, which reached its peak in the middle Cambrian and then gradually led to a retreat of the oceans, made for a humid climate. The oxygen concentration in the earth's atmosphere was still much lower in the early Cambrian period than it is today, but gradually increased during the epoch and was highest at the transition to the Ordovician.
At the dawn of the Cambrian, near the equator, there was a huge landmass that went down in history as the Gondwana, encompassing the continents of Africa, South America, Australia, and Antarctica. Even parts of today's China, Florida and Mexico and India belonged to this southern supercontinent, whose foothills reached into the northern hemisphere. North America, Baltica, much of today's Asia, and Siberia formed isolated, compared to today, differently positioned continental floes. Today's Europe was only partially present, belonging to two of these continental plaques. Cambrian sediments, which are often extremely valuable fossils for science, exist worldwide and are mainly exposed as the oldest layers of shale. This slate is composed of quartzites, phyllites and arkoses. Important deposits of shale-bound fossils are found in China, in the Rocky Mountains, Australia, but also in much of Central Europe, including Germany.
Flora and Fauna (plants and animals):
Life was concentrated in the Cambrian on the oceans, while the land masses of animals and plants were not yet settled. The constant increase in oxygen in the earth's atmosphere and seawater, as well as the gradually warming and mild climate, caused a real explosion of life on Earth in the Cambrian. In the Cambrian, living things developed for the first time, which gained their energy from oxygen breathing alone. Thus, the Cambrian spawned innumerable new forms of life, marked by a great diversity. Not only many species of sponges and worms appeared in the Cambrian, but also first cnidarians, arthropods of a more primitive character, and armpipers. Molluscs, especially gastropods and early forms of nautilus, as well as the predecessors of today's vertebrates already colonized the oceans. The Cambrian is important for the evolution above all else because many species of animals have formed lime-built outer skeletons and housings in order to protect themselves from predatory species. The development of the plant world, however, was characterized in the Cambrian only by the colonization of the seabed with planktonically living algae.