The Devonian Period Rora stiles, joslyn cassel and jesse ward

The Devonian Period was 419.2 million and 358.9 million years ago

The Devonian Period is named for Devon, England where the old red sandstone of the Devonian was first studied.

In the sea, the organisms that dominated were in the early part of the Devonian Period were bivalves, crinoid and blastoid echinoderms, graptolites, and trilobites. In the later part of the devonian period there was the first jawed fish.

First sarcopterygians, the lobe-finned fish, which eventually produced the first tetrapods just before the end of the Devonian Period.

It was about this time when the vertebrates started to move onto land.

During this time the super-continent Gondwana had taken place in the southern hemisphere, later in time the continent slowly drifted North.

Several episodes of global cooling may have lead to the Devonian Extinction.

The close of the Devonian Period is considered to be the second of the “big five” mass extinction events of Earth’s history.

During the Devonian period, about 375 million years ago, some of the fish developed legs and began to walk on land. These amphibians were the first animals with spinal cords to leave the water.

Some of the earliest vascular plants lived here, consisted of small plants by the end of the period there was ferns, horsetails, and seed plants that started to appear.

Many paleontologists believe that there were several extinctions over a short period rather than just one massive one.

Up to 70 percent of marine species died.

Near the end of the devonian period there was a major extinction that mostly affected the tropical community especially the reefs. This extinction happened because there was glacial conditions in the south polar region, which caused glaciation.

The plants increased the oxygen content of the atmosphere, which was important for the making of terrestrial animals.

The plant life on land was mainly made up of Lycophytes, horsetails and ferns that grew to large sizes. Archaeopteris were the first successful trees. Archaeopteris could grow up to 98 feet.

Works Cited

"The Devonian Period." The Devonian Period. Web. 20 Mar. 2017.

House, Michael R. "Devonian Period." Encyclopedia Britannica. Encyclopedia Britannica, Inc., 09 May 2013. Web. 20 Mar. 2017.


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