Cambrian

Cambrian

Definition:

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 marked by the development of a great biodiversity that 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 age is today divided by scientists in four series and a total of ten stages, many sections are not yet named.

Climate:

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.

Geology:

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, which belonged to two of these continental floes. 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 made up of quartzites, phyllites and arkoses. Significant sites of shale-embedded 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. Due to the constant increase of oxygen in the earth's atmosphere and in the seawater as well as the gradually warming and mild climate, a real explosion of life on earth occurred 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 life forms that were 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. Even molluscs, especially gastropods and early forms of nautilus, as well as the precursors of today's vertebrates already colonized the oceans. The Cambrian is especially important for evolution because many species of animals have formed lime-based outer skeletons and housings 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.

Summary

The Cambrian is a section of Earth's history that lasted from about 540 million years ago to 485 million years ago.

Climatically, the Cambrian, with high humidity and an average temperature of 20 to 21 ° C, was much warmer and more tropical than it is today.

A Cambrian explosion is the occurrence of almost all known animal tribes today, at the time of the Cambrian, including worms, sponges, arthropods and cnidarians.

Life took place only in the oceans. The supercontinent Gondwana was still unsettled in the Cambrian.