The Paleozoic Era

Sources

Cambrian Period (541-485.4 MYA)

Ordovician Period (485.4-443.8 MYA)

Paleozoic Era

Silurian Period (443.8-419.2 MYA)

541 to 251.9 Million Years Ago

Devonian Period (419.2-358.9 MYA)

From life starting in the ocean, to a variety of climate changing events, this era was marked with extreme changes to the Earth as we know it today!

Carboniferous Period (358.9-298.9 MYA)

Permian Period (298.9-251.9 MYA)

Silurian Period

(443.8-419.2 MYA)

• Cooksonia plant grew on land.
• Ostracoderms developed spines and horns to aid against sea scorpians, the Eurypterids
• Jawed fish appeared, like the enelognathus
• Some life died out but not as bad as an extinction event .

Devonian Period

(419.2-358.9 MYA)

• Earliest sharks
• The armored placoderms took their hold on the ocean
• Trees and early insects hit land!
• Some fish related species may have went up on land with 4 legs.
• 375 to 358 million years ago the late Devonian extinctions were caused by several drops of O2 in seas, some land animals survived. The placoderms did not.

Permian Period

(298.9-251.9 MYA)

• Synapsids, lived with large herbivorous reptiles like pareiasaurs.
• The Estemmenosuchus' were like hippos with armored heads.
• Climate became much more dry.
• 252 million years ago, Permian-triassic extinction event, may have been caused by volcanos killed lots of life on earth.
• 96% of marine life died
• 70% loss of species on land

Carboniferous Period

(358.9-298.9 MYA)

• Climate got warm and swampy, so insects became larger.
• Tetrapod’s started laying eggs on land!
• Amniotes put water inside the egg to protect it from drying out.
• Pangea started forming, some trees died due to climate changes and less moisture.
• Amniote split into two groups: synapsids and reptiles .

Ordovician Period

(485.4-443.8 MYA)

Biodiversity increased significantly with new species of brachiopods, bryozoans, and early fish like the jawless ostracoderms. Primitive moss like plants began covering the land.

• The moss may have spread too much, taking in too much carbon dioxide, causing the Ordovician-silurian extinction event.
• This event lost 86% of its marine species.

Cambrian Period

(541-485.4 MYA)

The Cambrian Explosion gave way to diverse, complex forms, including the first trilobites, arthropods, and mollusks. Predators and prey developed exoskeletons, shells, and the first eyes.

Sources & Citations

Bardet, Nathalie et al. “The Paleozoic Era.” Ocean Life in the Time of Dinosaurs. United States: Princeton University Press, 2023. Web.Prothero, Donald R. The Story of Life in 25 Fossils : Tales of Intrepid Fossil Hunters and the Wonders of Evolution. New York: Columbia University Press, 2015. Web. PBS Eons Series: https://www.youtube.com/watch?v=NOwbjOJjvjE&list=PLi6K9w_UbfFR_lBRq0PwTwBxQNUsrXRKf