Triassic

The Triassic was the first period of the Mesozoic Era and lasted from about 252 to 201 million years ago. It began after a large extinction at the end of the Paleozoic Era and marked a time when life on Earth slowly recovered and changed. During the Triassic, early dinosaurs, early mammals, and many types of reptiles first appeared. The period set the stage for the later Jurassic and Cretaceous periods, where dinosaurs became more widespread.

At the start of the Triassic, most of Earth’s land was joined together in one supercontinent called Pangaea. This giant landmass stretched across much of the planet and created large areas of dry land. Because Pangaea was so large, the climate in many regions was hot and dry, with few areas of heavy rainfall. Over time, cracks began to form in Pangaea’s surface, and the land slowly started to split apart. These early changes in continental shape affected shorelines, ocean currents, and the environments where plants and animals lived.

Much of life during the Triassic was shaped by recovery from the earlier mass extinction, which had removed many species from both land and sea. Reptiles became the most common land animals, and new groups began to appear. Some early dinosaurs showed up near the end of the period, though they were small compared to later species. Early mammals also appeared, usually small in size and adapted to surviving in limited environments. In the oceans, new types of fish and marine reptiles developed, helping rebuild food chains.

Plant life changed slowly during the Triassic. Many areas were covered with hardy plants that could survive dry climates, such as conifers, cycads, and ferns. These plants formed forests in regions that received more moisture. Fossils of Triassic plants show details of leaves, stems, and seeds that help scientists understand the environments of the time. Spores and pollen from ancient plants are also found in rock layers from this period.

The Triassic featured a variety of environments, including deserts, coastal plains, river systems, and shallow seas. These environments supported many different ecosystems. Some reptiles lived on land, while others adapted to living in water. Flying reptiles had not yet appeared, but some animals had gliding abilities that helped them move between trees.

The Triassic ended with another mass extinction about 201 million years ago. This event caused many species to disappear, including several large reptile groups. After this extinction, dinosaurs expanded and became the most common large land animals of the Jurassic Period. The Triassic remains an important period for understanding how life recovered after a major crisis and how early dinosaurs and mammals began to develop.