readx;? The Jurassic period (about 200 million years ago – 146 million years ago) was the peak of gymnosperms. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 ｉｎｆｏ

Invertebrates are mainly ammonites, bivalves, arrows, gastropods, leaf limbs, mesozoans, hexacutopods, echinoderm sea urchins.

Cartilaginous scleroths began to decline during the Jurassic and were replaced by whole-bony fishes.

Some of the most primitive mammals that appeared in the late Triassic period developed many new phyla through the diversity of the early Jurassic. Among them, polyodontids are the main herbivorous mammals, and the archaeomammals that appeared in the middle Jurassic are the ancestors of marsupials and placental mammals.

But under the threat of carnivorous dinosaurs, most mammals were endangered in the late Jurassic, and all the large animals were eliminated by carnivorous dinosaurs. At that time, the large and small dinosaurs of King's Landing occupied most of the ecological niche.

The earliest placental mammals appeared in the late Jurassic, and these animals belonged to the order Insectivores. Insectivores are as large as mice or small rats and feed mainly on insects, other arthropods and earthworms. Carnivora, Pterodactylas, and Rodents are all differentiated from the early insectivores. The order Insectivora includes hedgehogs, golden moles, moles, shrews, spiny shrews, hairy hedgehogs, Cuban shrews, and Madagascar hedgehogs, of which modern hedgehogs are descendants.

Mammals that are accustomed to living at night (those who live during the day have been eliminated), avoid the attacks of daytime dinosaurs, have a warm-blooded constitution adapted to nocturnal life (cold-blooded animals freeze to death at night), have a mouse-sized body that can hide in underground burrows (large mammals have been delivered to the dinosaurs' mouths), and have a small appetite (those who eat too much eat take too long, so that they need to move outside the cave for a longer time, increasing the danger of encountering enemies), and can quickly fill their stomachs. These characteristics allowed it to develop a large number during the long period of Jurassic and White Age, so that a small number of them were able to escape the catastrophe of the extinction of dinosaurs at the end of the White Age.

Another type of dinosaur, the sauropods, was most abundant in the Jurassic: carnivorous dinosaurs and bulky plant-eating dinosaurs.

The marine reptiles are mainly ichthyosaurs and plesiosaurs, which are important members of the marine environment.

Dinosaurs became the rulers of the land. Ornithischian dinosaurs, with the exception of some early taxa, were four-legged and plant-eating. Ornithischian dinosaurs were gentle and non-aggressive, so they often became the food of carnivorous dinosaurs.

Stegosaurus, quadruped walking with an erect bony plate on its back and two pairs of bony spurs on its tail.

Ankylosaur dinosaurs were short and stout, covered with bony decks, and fed on plants.

Ceratosaurus is a four-legged vegetarian dinosaur. The posterior part of the skull enlarges into a cervical shield.

The main characteristics of the swollen cephalic dragon are that the skull is thick, the jaw foramen is closed, and the pubic bone in the pelvic is crowded out by the ischial bone, which does not participate in the formation of the belt.

Characteristics of theropods: carnivorous, bipedal, with sharp claws at the ends of the toes, sharp teeth like daggers or knives in the mouth, and often serrated on the anterior and posterior edges of the teeth. Tyrannosaurus rex is its famous representative.

The huge and ferocious Tyrannosaurus rex (the most perfectly evolved, the most attacked, has no weaknesses, and has a very thick body), the petite and vigorous Velociraptor, and the bizarre and extremely huge Spinosaurus (the largest carnivorous animal ever seen in the history of Earth), these dinosaurs were all theropod dinosaurs.

Theropod dinosaurs did not have a large range of motion on their forelimbs and could not rotate their palms back and forth, and their palms could only face down or backwards. The direction and range of motion of the wrist joints are also limited.

Sauropods differ from theropods in that they are all herbivorous dinosaurs. Some of these dinosaurs were 40 meters long and weighed 100 tons, making them the largest creatures ever lived on Earth.

Sauropods are four-legged, vegetarian giant dinosaurs that live around swampy rivers and lakes and can hide in water to avoid predators. It is divided into the group of rod-toothed saurosaurs and the group of spoon-shaped saurosaurs. The former is divided into Mamenxi Dragonidae, Brontosauridae, Diplodocidae, Megalosauridae, and Forkylosauridae. The latter is divided into the family of coil-footed dragons, demon dragons, brachiosauridae, and domed dragons.

In the late Jurassic, ecological competition was extremely fierce. In order to escape the threat of other carnivorous dinosaurs, some theropod dinosaurs began to climb trees, changed to arboreal life, then changed to jumping on trees, and then evolved to glide between branches, and finally until they could really fly, thus evolving into birds.

The advent of pterosaurs and birds was one of the most important changes in the history of animal life.

Ornithians are divided into archaeoavian subclasses, antiorniths, and modern orniths. The Archaeomycetes subclass are all fossil birds, including Archaeopteryx. The antiornithine subclass are all fossil birds, including the Santa Chinese bird, the Chaoyang bird, and the Liaoning bird. The present bird subclass (Neoornithis) includes fossil birds from the White Period and all extant birds.

Archaeopteryx of the Paleomyceaeus subclass was an intermediate link between reptiles and birds. Archaeopteryx is the ancestor of birds and lived in the Jurassic Ageauli Order, about 155 million to 150 million years ago. Archaeopteryx was about the medium size of today's birds, with wings that were round at the end and a tail longer than its size, Archaeopteryx had tiny teeth that could hunt insects and other tiny invertebrates, and its feet had long three-toed claws that closely resembled dinosaurs.

The emergence of Archaeopteryx, which mainly predates insects, has caused some winged insects flying between forests and green spaces to lose their airspace. And amphibians also changed their diets to insects. Despite so many disasters, the highly adaptable insect species have continued to maintain their populations with all their strengths.

In the early Jurassic, the unified continental pattern of Pangea provided enough space for the development of dinosaurs. At that time, the climate was warm, even hot, and the South Pole was far from Pangea. Various flora and fauna have spread from the ancient continent of the north, which was originally the main distribution, to the ancient land of Gondwana. This laid the foundation for the prosperity of the early Jurassic.

In the Jurassic period, reptiles represented by dinosaurs were highly developed, and the phyla were very complete, including sea, land and air, and even a few mammals and birds, which became the most prosperous and complete period of Mesozoic organisms. We can describe this period in terms of liberal capitalism. All kinds of animals have enough room for development, although dinosaurs dominate, but have not encroached on the living space of other animals, the number of carnivorous dinosaurs is not very large, so it can basically be described as living and working in peace and contentment. ”

However, no matter how good the environment is, if there is no restriction on development, it will not be able to maintain such a beautiful situation forever. By the middle of the Jurassic period, all biological development began to enter the saturation stage.

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