What was the Devonian period?

The

Devonian period is the fourth of the six geological periods that make up the paleozoic era, the oldest era of multicellular life on Earth, reaching about 542 to 251 million years ago. The Devonian period itself extends from about 416 to 359 million years ago. Devonian is sometimes called the "age of fish" due to the abundance and diversity of fish genera that have evolved during this time. Ammonity also appeared during the Devonian period. These nautilus organisms continue to be successful until the demise of dinosaurs only 65 million years ago.

The Devonian period was particularly important in the development of earthly life. The fish first developed their legs and began to walk on the ground like tetraps, and the first insects and spiders also colonized the ground. The ancestors Millipedes have already reached this several tens of millions before, during Silurian, but the Devonian period represented the first serious diversity of life on Earth. The fish legs have been made of muscular fins that would use the fish to push on small land bridges separating water formations.

The Devonian period also recorded the first vascular plants bearing seeds that produced the first real forests, which led to a virtuous cycle of accumulation of soil and plants using this soil. These forests contained various primitive insects, including the first spiders in fossil records, mites, springs and perished arachnides of similar mites called trigonotarbides. Trigonotarbiders were among the first land predators, while other organisms lived outside the litter of leaves and tree sap, as evidenced by small punctures in well -preserved plant fossils of the Devonian period.

calcium algae and coral stromatoporoids built large cliffs, thousands of kilometers long, around the edges of the Devonian continents, but at the end of the period Mass were erased. Building reefs did not get more than a hundred million years after various organisms were taken over for this activity.

Extinction that hitAt the end of the Devonian period, the organisms that lived most in shallow, warm water and the least cold water and ground organisms were influenced. About 364 million years ago, fish without jaw disappeared from a fossil record. 57% of the seabed families disappeared. Today is the justification of the cause of the Devonian extinction to a large extent speculative, even if the usual suspects were designed: the impact of asteroids, climate change, methane hydrate, etc.