DINOSAUR | THRIVED FOR NEARLY 180 MILLION YEARS
Dinosaurs are a varied group of reptiles belonging to the Dinosauria clade. They originally appeared between 243 and 233.23 million years ago, during the Triassic epoch, while the exact origin and chronology of dinosaur evolution are still being researched. After the Triassic–Jurassic extinction crisis 201.3 million years ago, they became the dominating terrestrial vertebrates, and their supremacy lasted through the Jurassic and Cretaceous ages. Birds are contemporary feathered dinosaurs that developed from older theropods during the Late Jurassic period and are the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event around 66 million years ago, according to the fossil record. Dinosaurs are split into two groups: avian dinosaurs, or birds, and extinct non-avian dinosaurs, which include all dinosaurs that aren’t birds.
Dinosaurs are a diverse group of creatures in terms of taxonomy, morphology, and ecology. Birds are the most varied group of vertebrates, with approximately 10,700 species. Paleontologists have identified over 900 different genera and over 1,000 different species of non-avian dinosaurs based on fossil evidence. Extant species and fossil remains of dinosaurs may be found on every continent. Before birds were recognized as dinosaurs in the early part of the twentieth century, most scientists assumed dinosaurs were lethargic and cold-blooded. The majority of research done since the 1970s, on the other hand, has shown that dinosaurs were busy animals with high metabolisms and multiple social characteristics. Some were carnivorous, while others were herbivorous. Evidence implies that all dinosaurs laid eggs and that many dinosaurs, both avian and non-avian, had the ability to create nests.
While dinosaurs were originally bipedal, many prehistoric groups had quadrupedal animals, with some being able to switch between the two. All dinosaur groups include elaborate display structures like horns or crests, and some extinct groups acquired skeletal adaptations like bony armor and spines. Many prehistoric dinosaurs (non-avian and avian) were large-bodied—the largest sauropod dinosaurs were estimated to have reached lengths of 39.7 meters (130 feet) and heights of 18 meters (59 feet), making them the largest terrestrial animals of all time. Preservation bias contributes to the misperception that non-avian dinosaurs were all massive, as huge, durable bones are more likely to survive until they are fossilized. Many dinosaurs were little, with some measuring only 50 centimeters (20 inches) long.
The first dinosaur fossils were discovered in the early nineteenth century, and Sir Richard Owen coined the term “dinosaur” (meaning “terrible lizard”) to describe these “huge fossil lizards” in 1841. Since then, museums around the world have featured displayed fossil dinosaur skeletons, and dinosaurs have become an indelible part of popular culture. Dinosaurs are frequently included in best-selling novels and films, such as Jurassic Park, due to their enormous size and supposedly terrible and bizarre nature. Dinosaur science has received significant funding as a result of public interest in animals, and new findings are constantly highlighted by the media.