Mesozoic era: in the world of fantastic giants
The Epoch of Reptiles
In the mass consciousness of the Mesozoic era has long been rooted as the era of the dinosaurs, who completely ruled the planet a little less than two hundred million years. In part, it is. But not only this is remarkable for this historical period from a geological and biological point of view. The Mesozoic era, whose periods (Triassic, Cretaceous and Jurassic) have their own characteristics, is a temporary subdivision of the geochronological scale, which lasted about one hundred and sixty million years.
General characteristics of the Mesozoic
During this huge temporary period, which started about 248 million years ago and completed 65 million years ago, the last supercontinent Pangea disintegrated. And the Atlantic was born. During this period, deposits of chalk on the ocean floor were formed by unicellular algae and simple organisms. Getting into the zone of collision of lithospheric plates,These carbonate sediments contributed to increased carbon dioxide emissions during volcanic eruptions, which significantly altered the composition of water and the atmosphere. Land life in the Mesozoic era was characterized by the dominance of giant lizards and gymnosperms. In the second half of the Cretaceous period, mammals, which are familiar to us today, began to emerge on the evolutionary scene, and dinosaurs hindered their full development. Significant temperature drops associated with the introduction of angiosperms into the terrestrial ecosystem and, in the marine environment, of new classes of single-celled algae, have disrupted the structure of biological communities. The Mesozoic era is also characterized by a significant reorganization of food chains, which began closer to the middle of the Cretaceous period.
Triassic. Geology, sea creatures, plants
The Mesozoic era began in the Triassic period, which replaced the Permian geological epoch. The living conditions during this period did not differ much from Perm. There were no birds and grass on Earth at that time. Some of the modern North American continent and Siberia was at that time a sea bed, and the territory of the Alps was hidden under the waters of Tethys - a giant prehistoric ocean.Due to the absence of corals, green algae were involved in the construction of reefs, neither before, nor after that, did not play the leading roles in this process. Also, a characteristic feature of life in the Triassic was the combination of old species with new ones that had not yet gained strength. The time of conodonts and cephalopods with straight shells was ending; some species of six-rayed corals, which are still to come, have already begun to appear; formed the first bony fish and sea urchins, having a solid shell, which does not decompose after death. Among terrestrial species, lepidodendrons, cordaitas and tree-like horsetails survived their long age. They were replaced by conifers well known to all of us.
Triassic animal world
Amphibians began to appear among animals - the first stegocephals, but dinosaurs, including their flying species, began to spread more and more widely. At first they were small creatures, similar to modern lizards, equipped with various biological devices for takeoff. Some had dorsal growths resembling wings. They could not make waves, but they were able to successfully descend with their help, like parachutists. Others were equipped with membranes, which allowed them to plan.Such prehistoric hang gliders. Sharovipterix had a full arsenal of such flight membranes. Its wings can be considered the hind limbs, the length of which significantly exceeded the linear dimensions of the rest of the body. During this period, small mammals hiding in burrows from the owners of the planet already hid in anticipation of their hour. Their time will come. So began the Mesozoic era.
This era has gained immense fame thanks to one Hollywood film, in which fiction is more than authenticity. The truth is only in one thing - this is the flourishing of the power of dinosaurs, which simply suppressed the other forms of animal life. In addition, the Jurassic period is notable for the complete disintegration of Pangea into separate continental blocks, which significantly changed the geography of the planet. The population of the ocean floor has undergone tremendous changes. Brachiopods were supplanted by bivalve mollusks, and primitive coquina - oyster clams. It is difficult to imagine the richness and magnificence of the Jurassic forests, especially on the wet coasts. These are giant trees and fantastic ferns, extremely lush shrub vegetation.And, of course, a huge variety of dinosaurs - the largest creatures ever lived on the planet.
The Last Dinosaur Ball
The largest events of this era in the plant world occurred in the middle of the Cretaceous period. The first flowers bloomed, therefore, angiosperm plants appeared, dominating the flora of the planet so far. Already there are real thickets of laurels, willows, poplars, plane trees and magnolias. In principle, the flora in that distant time acquired almost modern outlines, which is not the case with animals. It was the world of ceratops, ankylosaurs, tyrannosaurs and the like. It all ended in a grand catastrophe - the largest in Earth history. And the era of mammals. What eventually made it possible for a person to come to the fore, but that's another story.