Celtics6789+Silurian


 * __Silurian Time Period__**

**__Introduction__**

The Silurian time period is crucial in the Earth's development. The word “Silurian” is name after the Silures who were a fierce Celtic tribe that live in Wales during the roman times. The time period is divided into 4 subdivisions- Llandoverian, Wenlockian, Lundlovian, and Pridolian. The time period is also in the Paleozoic era. The Silurian time period occured from 443 to 408 million years ago! The humans have only been alive on the planet for 200,000 years; so imagine how long 38 MILLION years. After my time period, the next period is called the Devonian. During this time forests grew very tall. Fish with jaws split into 4 groups of classification but all of the groups are extinct except for 1 group that has evolved into 96% of the fish today. Also, the first amphibians appeared. The period before the Silurian was the Ordovician. It was 505 to 443 million years ago, during this period ice caps formed near North America. Jawless fish were very common. Most of the worlds land formed creating the continent Gondwana in the South Pole. Squids, octopus and mollusks appeared. 60% of invertebrates went extinct. The Silurian time period is complex in its own way, read more to find out why. **__Plate Tectonics__**



Around the world, plate tectonics are always moving. The continents were in a much different place during the Silurian time period than now. Massachusetts was already in the place it is today since most of the northeast of North America had formed. The major thing that was happening during the time was volcanic islands, Iaeputes ocean sediments, and the continent Avalonia collided with the northeast of North America. But still most of the land was in the South Pole including Gondwana. Most of the seas were shallow. The climate then was much different then modern times. If the humans had appeared during those times, we’d immediately die. The oxygen level was 30% less than today. The weather was basically between tropical and sub-tropical. The Silurian time period’s changes in tectonics plates really helped out the current world we live in. **__Landforms__**

A lot of interesting things formed during the Silurian time period. One landform that formed was the Appalachian Mountains. As North America grew bigger, the plates collided together causing mountains.There were also volcanoes in the Iaepetus Ocean that exploded a lot. Also, the northeast of North America almost completely formed during this period. In general many fish scale fossils were found in Wales, UK. Another fossil found was Eurypterid Remipes in Berlie Group, New York. The third fossil was a Dalmanites Limulurus that was found in Middleport, New York. The Silurian time period formed many things that we still have now.

**__Biotic__**

There were many incredible life forms during the Silurian time period. One great evolution during this period was that fish grew jaws.Most life was in the water during those times. In the Silurian time period, the first land plants appeared. The only other thing on land was arthropod. The trilobites had almost completely died off. A very well known arthropod during the Silurian was the Brantoscorpia that was 1 meter long. It had neurons to move which helped evolve into humans. A lot of other giant scorpions also roamed the earth. There were also many arachnids as well as other insects. A known land plant at the time was a caxonia. It used light to grow, and it eventually evolved into large forests like during the Devonian times. A lot of animal’s brains developed, creating memories, which of course evolved to the humans today. Also, a lot of vascular plants now had leaves. The Silurian time period was crucial in the earth’s production and survival.



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