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Transcript of Ordovician-Silurian
•Once, Gondwana made its way to the southern polar position, creating massive glaciers that started to form in Gondwana's center, A.K.A present-day Africa. These glaciers caused the
sea-levels to decrease majorly, creating a 20 million year
ice age with shallow seas, wiping out many species of sea life.
of total sea life was wiped out.
• Most life was in the sea during the Ordovician period,
and many sea creatures such as trilobites,
brachiopods and graptolites were reduced
End of Ordovician
• As the Ordovician period ended, Every thing went into place, sea levels rose to their normal levels, and temperatures started to average out.
Sea creatures with bones started to show, or, vertebrates, started to make their first appearance.
Meanwhile, on land, plants became more established, and started to grow along rivers and lakes on Earth.
These plants along the water started creating Earth's first wetland environments, for example: swamps, forests, etc.
And much later animals started to live on land.
The Silurian period ocurred 416 million years ago.
During the Silurian, reefs started to do their thing,
to their ecosystem, and they formed a complete new type of environment for sea life.
These types of corals aren’t the same as the ones now. The old corals were a host of tabulate and rugose corals, crinoids and sponges.
The Ordovician took place in Gondwana, 485.4 million years ago.
Africa, South America, Antarctica, and Australia formed together to form Gondwana, a super continent in the southern hemisphere. At first, Earth's climate was warm and wet, and sea levels rose 1,970 ft more than those of today.
Everything took place mostly in the seas.
Gondwana made its way south, from the north-east.