Devonian

Devonian period

Definition:

The Devonian refers to a temporal portion of the Earth's history, which began about 419 million years ago and lasted about 58 million years. It is divided into three series by scientists with the Lower Devonian, the Middle Devonian and the Upper Devonian, each of which has several levels. The name of this era was coined by the two British scientists Adam Sedgwick and Roderick Murchison in the first half of the 19th century and is derived from the name of the Devonian county of Devon. There, deposits of rocks from the Devonian era were first uncovered and scientifically studied. The Devon is characterized by an increasing colonization of land mass by plants and animals as well as a gradual decay of the large continents.

Climate:

The climatic conditions that prevailed in the Devonian were mainly characterized by warm, in many regions even tropical to dry and hot temperatures. Traces of large-scale icing are almost completely absent from Devonian times, suggesting that the temperature differences were significantly lower than in previous epochs and also compared to today. However, some glaciers could form in the polar regions, since at least on the south pole lower temperatures prevailed.

Geology:

As a result of the largely tropical climate, many new reefs have sprung up since the beginning of the Devonian, many of which today are evidence of reef limestones and sediments in Central Europe and North Africa as well as in North America. Evaporites such as rock salt and gypsum indicate that the dry climate in the Devonian also led to the rapid evaporation of some shallow seas in whose waters the dissolved mineral salts and ions were contained.

In the Lower Devonian, the land masses, as in the Ordovician and Silurians, although largely distributed to the southern Gondwana and the northern Laurasia, yet it came in this era gradually to a disintegration of these large continents. Gondwana, in particular, began to divide slowly as tectonic processes led to the formation of moats, slowly dividing Antarctica and Africa. Many mainland areas inside were flooded and brought with it a separation of North America from Africa. In Europe, the areas of present-day Great Britain and Scandinavia and parts of northern Germany stood out from the sea, while today's central Germany, Poland, Ukraine and other Eastern European countries were completely flooded.

Flora and Fauna (plants and animals):

The Devonian is significantly influenced by the conquest of the mainland by animals and plants, which developed rapidly in this epoch. Initially, the group of fish, both the jaw-free, bone-armored species and the archetypal rays and sharks, experienced explosive radiation. The freshwater was increasingly inhabited by the group of Crossopterygians, which today are considered the link in the development of fish to amphibians. In the upper Devonian, finally, the first amphibians such as Ursalamander spread to the land masses. Even wingless insects and scorpions spread rapidly in the late Devonian on the land masses. Connected with this, the land plants continued to develop. Towards the end of this era, the ancestors of the conifers and the first seed plants had already appeared. Until then, the primeval ferns had already spread across the continents and dominated the landscapes. Since there were no larger herbivorous animals in Devonian, the species were able to evolve rapidly and spread on the earth. Towards the end of the Devonian came to a mass extinction, but mainly affected species among the marine life.

Summary

The Devonian is a section of Earth history that lasted from 419 million years ago to 359 million years ago.


The flora and fauna at the time of the Devonian is characterized by a hitherto unprecedented biodiversity. Especially with the fish there is an explosive radiation.

The departure of the vertebrates, which for the first time in the course of the history of the earth, survived, at least temporarily, outside the water, took place in the Devonian.