In this article, I will analyze a timeline of the history of dinosaurs, starting with when scientists first began studying them and ending with why dinosaurs went extinct and also everything in between. I will also demonstrate a fun fact about why scientists believe they can recreate living dinosaurs within five to ten years. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay In ancient history, scientists believed that dinosaurs roamed the earth long before humans did. Fossils have been found all over the world confirming these claims. They also believed that, based on geological evidence, a giant meteor had hit the earth, which could have been the cause of their extinction. Researchers first began looking at dinosaurs during the 1800s, when they found the bones of a huge land reptile they called Megalosaurus. Sir Richard Owen, a British scientist, first invented the expression "dinosaur" and from there the word stuck. Scientists discovered dinosaur fossils all over the world and continued to study them until they found all different types of dinosaurs. “From there, dinosaurs were divided into numerous genera, and each genus into one or more species.” During this time, dinosaurs congregated and stayed close to each other in a landmass known as Pangea. Of course, once Pangea broke up, they began to spread around the world, which explains the fact that fossils are found everywhere. When we arrived in America, the first fossil found on US soil dates back to the 18th century and was a femur. “The first dinosaur fossil found in the United States was a femur found by Dr. Caspar Wistar, in Gloucester County, New Jersey, in 1787 (it has since been lost, but other fossils were later found in the area).” After the first discovery of this fossil, they soon began finding other fossils in the United States in the eighteenth century. Additionally, in 1800, Dr. Moody found a foot-long footprint of a hadrosaur that was also found in the United States. "In 1800 in Massachusetts, USA, Pliny Moody found 31 cm long fossilized footprints on his farm that Harvard and Yale scholars thought belonged to 'Noah's Crow'." Since then, many fossils were found in New England, but scientists never paid much attention to them since they were not as important to them as the first one was. The oldest dinosaur was Saltopus, a small carnivore that lived 245 million years ago. As these dinosaur fossils have only been found in Scotland, the UK holds the key to tracing the origin of dinosaurs. According to scientists, the type of dinosaurs that first walked this Earth were what they called "Labrador-sized" dinosaurs. They were dinosaurs the size of a Labrador Retriever and they kept that name for a while until they finally decided to name them Nyasasaurus Parringtoni. “It would probably have remained standing and lived near Lake Nyasa in Tanzania feeding on vegetation. Although it was the size of a dog, it had a five-foot long tail. Figure one shows a rough image of what the dinosaur would look like.” Scientists also had the idea that they resembled a Labrador due to the fossils they found, namely the upper arm and six vertebrae. Dinosaurs were believed to have evolved from other existing reptiles that already roamed the earth. “Dinosaurs evolved from other reptiles during the Triassic period, over 230 million years ago. THEdinosaurs evolved immediately after the Permian extinction, which was the largest mass extinction ever to occur on Earth” (Dinosaur Fossil). Other mammals, such as birds, were also evolving during the Triassic. Dinosaurs and birds came from an area that is now known as South America, but before when the continents were all colliding together. Here is a timeline of which dinosaurs roamed the world and what they were like, it also includes other mammals that populated the earth. During the time when the continents were organized together as a single supercontinent also known as Pangea, the dinosaurs remained close together but once they separated they slowly began to spread across the world. Dinosaurs lived on this earth for a long time before becoming extinct. They lived in a period known as the Mesozoic Era. This happened a million years ago, long before humans and Homo sapiens set foot on this globe. About 700 different species of dinosaurs are known to have existed. Scientists believe there could have been many more than 700. One research suggested there could have been as many as 1,000 different species. “The numbers will continue to fluctuate. Many of these different species have actually been given separate names based on little fossil evidence, sometimes just one tooth or one vertebra” (Taylor, 2016). There's always a new fossil discovery every year, so it's a little difficult to pinpoint an exact number of how many dinosaur species actually roamed the earth at one point, but this is a rough number of what scientists believe. It's also difficult to find out how many different species there are because sometimes when scientists find fossils they think it's a new species they haven't studied but once they dig deeper they realize it's actually a species they haven't studied . they studied previously. “When skeletons are compared more closely, we sometimes find that animals previously classified into two or three different species are actually one species” (Taylor, 2016). A lot of it has to do with the difference in skeletal details and the difference in sexes, ages or diseases between individuals. Ultimately, the way dinosaurs would feed and maintain themselves would be by simply eating their vegetables, right down to the leaves and plants. The grass at that time was not fully developed, so they could not eat it. Some ate lizards, turtles, eggs, or early mammals, but most dinosaurs ate their vegetables. By now everyone knows why dinosaurs became extinct or at least has an idea of ​​how it happened. It is believed that during the age of dinosaurs, an asteroid, comet, or meteor the size of two football fields made such a strong impact on the earth that it almost destroyed most of what was on the earth. This event is known as the Cretaceous-Tertiary or KT extinction. “For many years, paleontologists believed that this event was caused by climatic and geological changes that disrupted the dinosaurs' food supply.” It wasn't until the 1980s that scientists discovered the theory failed and landed on the idea that it was a comet. Of course these are many theories because there is no proof of them. Scientists say that if the cause of the extinction was a comet, evidence of radiation dating back to that era would have been found on the Earth's surface. “In 1956, Russian astronomer Joseph Shklovsky became the first scientist to consider extinction due to a single catastrophic event when he theorized that a supernova flooded the earth with radiation that could have killed the dinosaurs.” Of course, in 1950 this theory was considered just because.