Epochs of the Mesozoic Era

The Mesozoic Era (255-64 million years ago), is called the age of dinosaurs. This middle age group is important for dramatic changes in the animal, and plant kingdoms. It is during this time the first mammals appeared, and the first birds. It is during this time plants begin to flower, and modern insects flourish.

Broken into three major time periods, Triassic, Jurassic, and Cretaceous.

Triassic Period 250-206 million years ago

Middle Triassic Period (227 million years ago)	Late Triassic Period (205.7 million years ago)

The Triassic period was named in 1834 by the German geologist Friedrich August Von Alberti (1795-1878). The name derived from a three part division of rock types in Germany. The Triassic Period began with a massive extinction (the largest known in geological history). Because of the mass extinction of 95% of the animals and 60% of the plants, and the rearrangement of the continental masses allowed animals like dinosaurs and mammals to proliferate. There was one single continental mass, a super continent named Pangaea. The temperatures on land were dry and warm. Seed plants began to dominate the land. Conifers, and ginkgoes dominated the Northern Hemisphere, and Glossopteris (seed ferns), tree ferns, horse-tails, and cycads dominated the Southern Hemisphere. Mammal like reptiles dominated the early landscape. Insects began a complete metamorphous between the stages of larva and adult. They slowly died out and were replaced by dinosaurs. The first dinosaurs appeared in the Late Triassic Period, they were small two legged carnivores, and larger plant eaters that were quadrupeds (walked on four legs). One of the a number of species that evolved during this time has survived until modern times, the crocodiles.

Jurassic period 206-144 million years ago

Early Jurassic Period (180.1 million years ago)	Middle Jurassic Period (159.4 million years ago)	Later Jurassic Period (144.2 million years ago)

The Jurassic Period began with another extinction of species that were abundant during the Triassic Period. Pangaea began to break apart and form smaller continents seperated slowly by oceans. The temperature became cooler and rainfall abundant. The conifers forest began coverning vast amounts of land, and ginkgoes, palms, tree ferns and horse-tails flourisched in the moist climate. Giant-sized plant-eating dinosaurs first began to appear. This brought a need of growth, and strength in carnivorus dinosaurs. The first birds appeared, to compete with the pterosaurs. The ancestors of present day bees and flies began to populate the land.

Cretaceous Period 144-65 million years ago

Early Cretaceous Period (98.9 million years ago)	Late Cretaceous Period (65.0 million years ago)

The Cretaceous period, durning this time the continents have nearly reached their present day positions, and the mountains began forming as the plates sliped, slide, and slam into each other. The temperature of the planet was still in a cooling down stages. and the seasons became distinct. The first flowering plants appeared, providing an abondance of food soucres. Oak, Maple, walnut, and beech trees began to sprout right next to conifers and cyacads and ferns. The dinosaurs formed grazing herds which were preyed upon by carnivorus dinosaurs. Some of the herbivores developed armor like defences to protect themselves from preditors. Snakes and other small mammals appeared on land. and the crocodiles lived in fresh water pools. Birds, and sauring dinosaurs began to share the skies with the first moths. Giant Turtles and lizard like animals lived and survived in the oceans.

The pictures used on this page are from the following sites.

Paleo-Maps: Dinosauricon

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