In the previous article, we introduced dinosaurs as a group. Now it is time we move on to the tropical Jurassic period and discuss the time of their greatest dominance. However, the Jurassic is also a time of great changes in Earth’s climate and geology.
The Jurassic Period Forests
Due to the warm and wet climate, in the Jurassic, plants flourished. Their development helped other species to evolve and created more food chains. Amongst conifers and other gymnosperms from the previous periods, new species appeared. However, most of them did not make it until today. Moreover, plants similar to palm trees- cycads-also appeared. They even managed to survive until today, though in quite different forms. We can find them in both the Americas near the equator, Africa, Asia, and Australia, which proves that they were once a joint landmass. Despite that, seed ferns were still hanging good in their ecological niches, first modern coralline algae also appeared.
The Time of Dinosaurs and The First Birds
In the Jurassic period, dinosaurs were at the peak of their dominance. First of all, many of them were herbivorous, which made them the primary consumers in their food chains. They had various adaptations, depending on the type of plants they fed on. Moreover, some of their specializations were also a part of an ever going predator-prey race. Many predatory dinosaurs, such as Allosaurus, hunted them, therefore closing the food chain. Dinosaurs were for sure a massively diverse group, similar to today’s mammals. We might think we know how they looked like, however, new studies still emerge, revealing new details. One of the new interesting conclusion is that dinosaurs were probably feathered creatures. Evidence also shows that dinosaurs were ancestors of modern birds. The first forms between dinosaurs and birds evolved in the Late Triassic. Until then, pterosaurs ruled the air, with many adaptations to flying similar to today’s birds.
Changes in Earth
As we already said, the climate was generally wet and warm. Two major oceans were nearly tropical and there was probably no glaciation. However, due to the continuing breakup of Pangea, the situation got a bit more complicated. Firstly, Pangea separated completely into Laurasia and Gondwana. Due to that, the Pacific Ocean emerged in the west. Later on, the Gondwana also started breaking up, creating the Indian Ocean. Similar geology and some species prove that land masses separate today were once joint. That includes, for example, South America and Africa (if you look close on the map you can even see that their modern shapes match like puzzles). In addition, the sedimentary rock composed of skeletons of marine organisms, found in the Jura Mountains in Europe inspired the name of the period.
The End of the Jurassic Period
The end of the Jurassic period comes quite typically with an extinction event. No one knows what caused it, or if it even can be called an event, not a series of slow graduate ecosystem changes, not related to one another. However, that one was not extremely huge and did not revolutionize the entire life on Earth. Most of the dinosaurs manage to survive and they were quite fine until the next period. Amongst the dinosaur victims, we can find Sauropods- long-neck, tall herbivores. However, marine life suffered way more. Many marine reptiles went extinct, so did some bivalves and ammonites. We do not count that extinction to the ‘big five’ of mass extinction, we cannot even call it a huge event. Scientists typically classify it as a minor extinction event.
Jurassic Period Evidence
There are various pieces of evidence from the Triassic period. For example, there is proof that dinosaurs and reptiles adapted to all environments. In the seas, there were Plesiosaurs- one of the largest marine predators. In the air, there were of course pterosaurs, however, dinosaurs also appeared there. The Archaeopteryx evolved directly from a dinosaur and was the form between dinosaurs and birds. On land, there were extremely tall vegetarian brachiosaurs and predatory Ceratosauruses with an impressive collection of teeth and horns. In the freshwaters despite dinosaurs ancestors of the crocodiles appeared. Among other fossils, we can find a lot of plants or today’s coal. The first mammals were quite small and occupied only several niches. We can also find fossils of first modern amphibians, for example, salamanders.
I hope that the article helped you understand the second period from the Mesozoic era. If you enjoyed it, please share it with family and friends. In the next one, we will discuss dinosaurs more deeply, trying to understand what made them the dominant group on Earth. Stay tuned for updates and also feel free to contact me. You can use the contact form below or find my email address in the team’s section of the page.