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Dinosaurs are a group of reptiles [sub-branch of Dinosauria, which first appeared in the Tam Diep about 243–233.23 million years ago, despite the exact origins and timelines in the evolution of the They are currently active research topics. Since the Tam Diep-Jura extinction event (201.3 million years ago), the dinosaurs became the most dominant group of vertebrate animals throughout the Jurassic until the end of the Cretaceous period, when the event was great. The Cretaceous-Ancient-Near (66 million years ago) strain took place to extinction most of the dinosaur groups and 3/4 species of animals and plants on Earth, marking the end of Mesozoic and beginning of Dai Tan. Born. The fossil record shows that the bird was a feathered dinosaur, evolved from the Late Jurassic dinosaurs. Hence, the bird is the only surviving descendant of dinosaurs today. Dinosaurs can therefore be divided into ostrich dinosaurs — all kinds of dinosaurs other than birds, and birds.
Dinosaurs are a diverse group from taxa, morphology to ecology. Birds, with more than 10,000 living species, are the most diverse group of vertebrates apart from the sea bass. According to the fossil record, paleontologists identified 500 genera and more than 1,000 species of ostrich dinosaurs. Dinosaurs are present on every continent, through surviving species (birds) as well as fossils. During the first half of the twentieth century, before birds were considered dinosaurs, most of the scientific community believed dinosaurs were sluggish and variable animals. However, most studies in the 1970s showed that dinosaurs were active animals with a high metabolic capacity and well adapted to social relationships. Some eat plants, others eat meat. There is evidence that all dinosaurs laid eggs, and nest building was a secondary trait of all dinosaurs, birds and birds.
The dinosaur ancestors walked on two legs. However, many dinosaur limbs traveled on all fours, and some limbs could change between the two forms. Horn and crest structures were common in all groups of dinosaurs, and some groups even developed skeleton modifications such as tissue armor or spikes. While modern dinosaurs (birds) were quite small to facilitate flight (of course there were a few birds that couldn’t fly), many dinosaurs had very large bodies. The largest lizard-footed dinosaur genus can reach 39.7 meters (130 feet) in length and 18 m (59 ft) in height. Even so, the idea that dinosaurs are mostly big is wrong, as large fossils tend to be held longer. Many dinosaur genera were quite small, for example Xixianykus was only about 50 centimeters (20 inches) long.
Since dinosaur fossils were first recorded in the early nineteenth century, their fossil skeletons or models have become favorite attractions at museums, and dinosaurs have become part of world culture. The enormous size of some dinosaur groups, as well as their paranormal and monster-like nature, have ensured their appearance in best-selling books and movies like Jurassic Park. Public enthusiasm has led to significant funding for dinosaur research, and new discoveries are regularly updated by the media.
Using one of the above definitions, dinosaurs can be generally described as lizards with hind legs held upright below the body. Many groups of prehistoric animals are commonly perceived as dinosaurs, such as fish lizards, river lizards, snake-necked lizards, dragonflies and pelycosauria (especially genus Dimetrodon), but are not classified as a Scientifically like dinosaurs Dinosaurs were the dominant terrestrial vertebrates of the Mesozoic era, especially during the Jurassic and Cretaceous periods. Other animal groups have limited size and ecological niches; Mammals for example rarely exceed the size of a domestic cat, and most are small rodent-sized predators.