The Triassic Period

Taylor O'Connell- Norman- Period 6

about 248 to 199 million years ago

Definition Words-

  1. Archosauromorpha: is made up of three Greek roots that mean "ancient lizard forms"
  2. Proliferate: Increase rapidly in numbers; multiply: "magazines proliferated in the 1920s".
  3. Dicynodont: any of a suborder (Dicynodontia) of small herbivorous therapsid reptiles with reduced dentition
  4. Ginkgo trees: large trees, normally reaching a height of 20–35 m (66–115 feet), with some specimens in China being over 50 m (164 feet)
  5. Sundering: Split apart
  6. Conodonts: snake-like creatures (having tooth-like projections) elements of 0.3 mm to 3 mm in length, with a shape varying from coniform (tooth-like) to ramiform (bars) to pectiniform (plates).
  7. Ichthyosaurs: looked like fish, they were not; averaged 2–4 meters (7–13 ft) in length; with a propoise-like head and a long, toothed snout. Built for speed, like modern tuna, some ichthyosaurs also appear to have been deep divers, like some modern whales; could swim at speeds up to 25 mph
  8. Synapses: a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another cell (neural or otherwise)

Background information on the Triassic Period-

The Triassic Period is the first geological period of the Mesozoic Era or "Age of Reptiles". It was during this time that Archosauromorph reptiles achieved dominance on land, and many types of marine reptiles roamed the seas. The Triassic period was a time of change, with some plants becoming extinct and others starting to proliferate. Ferns, cycads and conifers were common during this period. The Middle Triassic period, for its part, was notable for the many changes that took place as well. Suddenly, there were more carnivores and four-legged predators.

Organisms in the Period-

Therapsids were the dominant mammal-like reptiles of the period. There weren't that many dinosaurs in the early Triassic period. Most of the animals that roamed the earth were reptiles and amphibians.The lystrosaurus was a dicynodont about the size of a dog. Its fossils have been found all over the world.

What was earth like?

Because the middle of Pangaea was so far from the oceans, it was very dry there, like a desert. The whole world was generally pretty warm all through the Triassic period. Even at the North and South poles, there wasn't any ice. Most of the ferns died out, while the new pine trees took over as the main plants on Earth, even at the North and South poles. Ginkgo trees also developed, and possibly the first flowers. The types of plants and animals were different in southern Pangaea than they were in the north. In the south, there were a lot of warm-blooded reptiles, but the north had more cold-blooded reptiles like the turtles that evolved about 215 million years ago. Throughout this period, the cold-blooded reptiles generally did better than the warm-blooded reptiles. But at the very end of the Triassic, about 200 million years ago, the warm-blooded reptiles evolved into the first flying reptiles - the pterodactyls - and others evolved into the first mammals.

What was happening with Pangaea?

Pangaea had stayed the same for millions of years, covering about one quarter of the world’s surface, but by the latter portion of the Triassic period, tectonic forces at last had their way and Pangaea began to fracture.

The first phase of deconstruction involved the sundering of the eastern landmasses allowing most of the water from the Panthalassic Ocean to flow westward, creating the Tethys Ocean and flooding many continental margins. After the Tethys Ocean formed, Pangaea continued to tear apart as the second phase of dismantling produced two large groups of continents; Laurasia held North America, Europe, and Asia while Gondwana held South America, Africa, Antarctica India, and Australia. As these two continental groups split from one another, a deep rift appeared along the eastern borders of what would become the North American continent. This great trench, called the Tethys Seaway, separated North America from Europe and Africa and would eventually form the Atlantic Ocean. Other geological changes included the formation of mountains (in China, Japan and along the western coast-lands of North and South America) which in turn prevented the flow of damp air from the oceans, further intensifying the arid environments in the continents.

The ending of the Triassic Period

The Triassic period ended with a mass extinction accompanied by huge volcanic eruptions about 208-213 million years ago. The super continent Pangaea began to break apart. 35% of all animal families die out, including virtually all labyrinthodont amphibians, conodonts, and all marine reptiles except ichthyosaurs. Most synapses, which had dominated the Permian and early Triassic, went extinct (except for the mammals). Most of the early, primitive dinosaurs also went extinct, but other, more adaptive dinosaurs evolved in the Jurassic. No one is certain what caused this late Triassic extinction; possibilities include global cooling or an asteroid impact. A 210 million-year-old meteor crater surrounding Manicouagan Reservoir, Quebec, Canada, may be the remains of the culprit. This extinction allowed the dinosaurs to expand into many niches that were now unoccupied. Dinosaurs would become increasingly dominant, abundant and diverse, and remained that way for the next 150 million years.