Life of the Permian Period

(Mesothelae)

300 million years ago, when the Permian Period began, the earth was covered in swampland and towering tree-like ferns. The atmosphere was over a third oxygen, and huge arthropod predators roamed the planet. Mesothelae were a foot long spider like creature that ambushed its prey from holes dug in the ground. The queen of the skies, Meganeura had a wing-span measuring about a meter, and it stalked its prey from above. With nearly impenetrable armored plates, arthropleura, an ancestor of centipedes, the arthropleura grazed the dense foliage. It was as long as a car and could rear up to look you in the eye. Also roaming the swamps was the Petrolacosaurus, the first reptile. With its new scaly skin, it could retain moisture and venture far from water, unlike any amphibian before. It also had the first complex heart, allowing it to move faster and longer distances than its predators. Giant amphibian hunters stalked the waters throughout the swamps.

As the oxygen decreased, and the climate became drier, many of the large arthropods died out, allowing the reptiles to evolve without much competition. The Petrolacosaurus evolved to create "mammal-like reptiles." These mammal predecessors grew an enormous sail on their backs to help regulate body heat. Two similar species called the Edaphosaurus and the Dimetrodon dominated the land. The Edaphosaurus was about the size of a hippo, it was an herbivore, and it roamed in herds. The Dimetrodon was usually a meter longer than the Edaphosaurus and was a vicious predator. Modern lions eat 70% of a carcass. A Dimetrodon ate 90%. The Dimetrodon was one of the first to develop specialized teeth, such as incisors and canines. They also developed some of the first maternal protective instincts: the mother protected her eggs for seven months until they hatched. As the climate and geology changed, these enormous reptiles began to evolve.

(Gorgonopsids)

At about 280 million years ago, the land masses came together to form the super-continent Pangea. Pangea stretched from pole to pole and in its center was the largest desert in the history of the Earth. Life had to adapt to this harsher landscape. Scutosaurus was 3 meters long and weighed about a ton. They traveled in herds and are distant relatives of turtles. They swallowed stones to help digest what little vegetation they could forage. The Scutosaurus were often hunted by a group of mammal-like reptile predators called gorgonopsids. There were multiple varieties of gorgonopsid, but on average they were about 5.5 meters long and evolved the first set of saber teeth. Burrowing in the sand of desserts were the Diictodon. They were about the size of a small dog and dug spiral burrows deep into the earth. They often lived in pairs to increase chance of survival. The earth began to change again, forcing life to adapt with it.

The Earth began to heat up due to increased volcanic activity pumping greenhouse gasses into the atmosphere. A massive global drought began to dry up many water sources inland of the ocean. Amphibian predators inland, like the Labyrinthodont, measuring at 5 meters, began to die out. With the constant drought and scorching heat, along with the added disaster of a massive meteor collision, 90% of life began to die. Gorgonopsids and Scutosaurus went extinct. The tiny Diictodon survived and evolved into the Lystrosaurus. Lystrosaurus soon made up 50% of life on earth. At about 2.5 meters, it was a small herbivore. Constantly hunting the Lystrosaurus were the Therocephalians. They measured at about 2 meters and had a highly lethal, venomous bite. Most notable in that time period though was the Euparkeria. It was a small insect-eating reptile. I had a revolutionary hip that allowed it to run on two legs, giving it extra agility and speed. It was a direct ancestor of dinosaurs. As the ferocious dinosaurs began to appear, the "mammal-like" reptiles began gave up their position as dominant group of animal on Earth until, of course, the dinosaur extinction 65 million years ago. They lived in the background, waiting for their time come out of the shadows.

-Max P
-Zach H

References

National Geographic. (n.d.). Permian period. National Geographic. Retrieved from

    http://science.nationalgeographic.com/science/prehistoric-world/permian/

British Broadcasting Corporation (Director). (n.d.). Walking with monsters

    [Television webisode]. In British Broadcasting Corporation (Producer),

    Before the dinosaurs. Retrieved from

http://www.dailymotion.com/video/xknl8n_bbc-walking-with-monsters-2-of-3_tech

British Broadcasting Corporation (Director). (n.d.). Walking with monsters

    [Television webisode]. In British Broadcasting Corporation (Producer),

    Before the dinosaurs. Retrieved from http://www.dailymotion.com/video/xknl8p_bbc-walking-with-monsters-3-of-3_tech

Mesothelae [Image]. (n.d.). Retrieved from http://walkingwith.wikia.com/wiki/ 
     Mesothelae

Gorgonopsids [Image]. (n.d.). Retrieved from http://hi.baidu.com/6500nya1/item/ 
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