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Mesozoic Era Commences
The Mesozoic Era begins at the end of the Paleozoic. Begins due to the mass extinction that brought an end to the Permian Period. Began around 248 million years ago. It is marked by the Permian Extinctions, and when Pangea is formed. -
Period: to
Mesozoic Era
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Beginning or the Triassic Period
The Triassic Period begins with the mass extinction of a large amount of marine life and plant life. All of Earths mass was concentrated at one super continent called Pangea. Began approximately 243 million years ago. -
Lifeforms Begin to Grow
The sea waters begin to protrude into the continent through Tethys. Made climate conditions become arid, and dry. As the water dryed, it freed up the land allowing animals to colonize the whole land mass. -
Climate Changes
At the beggining the climate was mostly cold and most of the Earth was covered with glaciers. As the Triassic Period progressed, Pangea began to become very dry due to its shape. It made all inland areas dry and only the coast was moist and cold. -
Lifeforms Evolve
Rhynchosaurs were flourishing during this time and the Squamota group was just as abundant. The first major animals would include reptiles. -
Plant Life Begins Developing
Although the climate did not allow many plant forms to grow and develop, the dry weather allowed Cycads and Ferns to grow without a problem. -
Mountains Develop
Near the ocean shores of Pangea, mountains just began to form. One plate was being forced under one another, which were the beginnings of the Sierra Nevada mountain range. Although most of what is now America was underwater, mountains still formed. -
Dinosaurs
The earliest dinosaurs were no more than 6 inches in length. They were different from reptiles thanks to their bone structure, and the fact that they are warm-blooded rather than cold-blooded. Although Dinosaurs were evolving, they would not come to dominate until later during this Era. -
Reptiles Dominate
The warm and dry conditions of the supercontinent Pangea allowed reptiles to dominate. They dominated most of the air, land and sea. -
Mammals
Mammals began to evolve from the earliest synapsid reptiles. They were very small, and would fully evolve for millions of years -
More Species Evolve
During the mid Triassic Period, The Belemnites were a completely new invertebrate species that began evolving during the Triassic period. Belemnites were a form of mollusk. A modern day relative to Belemnites would include Squids. -
Reptiles Rule The Ocean
The huge ocean surrounding Pangea, the Panthalassia Ocean, was also ruled by reptiles. Ichthyosaurs developed in the Triassic period. They had fish-like bodies and spent their whole life in the ocean. Although they lived in water they had lungs, not gills. These fish also had a large amoutn of bones, compared to all other animals during this time. Plesiosaurs also developed. -
Reptiles Rule the Air
Near the end of the Triassic Period, many reptiles began developing wings, and learning to fly.. These animals were called pterosaurs. -
Minor Extinction
The Triassic Period in all was a time of transition. Many important plants and animals began growing during this time. Only about 20% of lifeforms died out during this extinction, and the species that survived would come back and dominate the Jurassic Period. Pangea also breaks apart slightly due to plate tectonics moving. Ended about 206 million years ago. -
Jurassic Period Begins
Began about 206 million years ago. Pangea continued to split apart, which caused volcanoes to erupt along the Tethys sea floor. -
Mountain Ranges
Plates began colliding, folding and uplifting. Due to the faults in the plate tectonics, volcanoes began to erupt, and mountain ranges began forming. The mountians that strecth from British Columbia through North America and into South America began to develop. -
Climate Control
The climate became warm and stable, which allowed a number of new species to form and others to evolve, and increase in population. As sea water began to get warmer, the clitmate became more humid and tropical. -
Invertebrate Species
As time went on the amount of invertebrate species began to increase. Belemnites and ammonites were the most important species. Gastropods were plentiful during this period. -
More Sea Creatures
Bony fish, sharks and rays were found a lot in tropical seas. The ammonites, belemnites, and fish were all excellent hunters. Ichthyosaurs and plesiosaurs became overwhelmingly abundant. They also shared the oceans with crocodiles. -
Abundant Plant Life
As a result of the climate change, plants were able to grow thick and tall. Cycads were more abundant than ever. The Jurassic period is often referred to as the Age of Cycads. The ammount of plant life allowed for dinosaurs to dominate this time period. -
Common Error
Although many people believe the Tyrannosaurus Rex and Velociraptors were the major dinosaurs during this time, they werent around until later in the Cretaceous Period. -
Major Dinosaurs
The major dinosaurs of the Jurassic Period consist of the sauropods. These were massive dinosaurs who stood on four legs, with long necks and long tails. The Brachiosaurus could grow to be 55 tons. -
The Allosaurus
The Allosaurus were vicious carnivores. They walked on two legs and could grow to be 35 feet tall. Very similair to the Tyrannosaurus Rex. -
Herbivores
The huge sauropods, and the stegosaurus were herbivorous dinosaurs. The stegosaurus was a form of ornithopod. All ornithopods were plant-eaters -
Huge Birds
The very first birds began developing during the late Jurassic Period. Archaeopteryx were the first species of birds. They had some characteristics of dinosaurs, and also many from modern day birds. -
Mammals
As the Jurassic Period continues to the end, mammals became more and more abundant. The largest mammals were still quiet small. Mammals did not play a large role during this period at all. -
Pangea Splits
As the Earth shifted, the supercontinent Pangea finally split into two continents. The two new continents were Laurasia and Gondwana. -
The End of The Jurassic
Near the end of the Jurassic Periodtheir was a minor extinction. Most of the stegosaurid and enormous sauropod dinosaurs became extinct. Nobody knows what caused this extinction to occur. Ended about 144 million years ago. -
Cretaceous Period Begins
The Cretaceous period about 144 million years ago. It was marked by a minor extinction at the end of the Jurassic Period. Many animals similair to present day clams were killed during this extinction. -
Formation of Continents
As Laurasia and Gondwana continued to separate, they began to resemble more present day continents. South America and Africa broke off from Gondwana. The North Atlantic Ocean and the South Atlantic Ocean also became more distinct. -
Raising Sea Waters
As the Atlantic Ocean became wider, a large chain of undersea volcanoes began forming. Due to the formation of these volcanoes, large amounts of water was displaced, causing sea levels to rise hundreds of meters. -
New Dinosaurs
This is the first time the ceratopsian dinosaurs were developing. The most common ceratopsian dinosaur is the triceratops. -
Tyrannosaurus Rex
This is the first point in history when the Tyrannosaurus rex became the "king" of dinosaurs. He was a type of theropod. -
Flowering Plants
The rise of flowering platns was perhaps the most important event occuring in the Cretaceous Period. The earliest trees to develop flowers were the magnolia and maple trees. -
Placental Mammals
Although mammals had been around for quite some time, this time marked the beginning of placental mammals. These mammls develop offspring from inside their bodies, instead of laying eggs. The earliest placental mammal was the Eomaia Scansoria -
The KT Event
The KT Event marks the end of the Cretaceous Period. Its is the mass extinction of nearly 70% of marine animals and 15% of landforms. Its also destroyed most vegetation. All animals over 50 pounds were wiped out, which included most dinosaurs. The only descendents of dinosaurs are modern day birds. he Ammonites, Belemnites, Icthyosaurs, Plesiosaurs, and Mosasaurs would become extinct forever. -
Why It Happened
The most common theorie as to why this happened is that a meteor hit the Earth at the Gulf of Mexico. This caused many volcanoes to erupt causing the smoke and smog to cover over the sky, hiding the Earth from any and all sunlight. -
A New Era Arrives
Now that all large reptiles and dinosaurs were out of the way, mammals could come in and flourish. This event marks the beginning of the Cenozoic Era. It wouldn't be long until mammals began to rule the earth. -
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THANK YOU!
By:
Frankie Donnelly, Brooke Koerner, Sara Coons
