The earliest conclusive evidence of the evolution of dinosaurs dates their origins to 230 million years ago. They are believed to have evolved from other reptilian species and developed certain defining characteristics, such as specialized hip and leg bones.Know More
Earlier fossils have been discovered which may predate previously uncovered archaeological evidence. A previously unknown genus of archosaur could push the time period back another 10 million years, while footprints discovered in Europe may place the date back to 250 million years. So little evidence remains from so long ago that it makes it difficult to pinpoint the exact date, year or millennium for a given animal type to have evolved.
What is known, as of 2014, is that the animals referred to as dinosaurs first appeared in the late Triassic period and remained in existence as a group for more than 190 million years. This has been determined based on the depth at which fossils have been found and through the use of radio-carbon dating which allows archaeologists to determine how old an item is based on the constant decay rate of carbon isotopes contained in all matter on Earth. This method is also used in geology when determining the age of rock formations or sedimentary layers.Learn more about Dinosaurs
There are a few well-researched theories about why dinosaurs are extinct; one of the most prominent theories hypothesizes that a massive asteroid impact killed off the dinosaurs. Another states that heavy volcanic eruptions across the Earth may have been responsible.Full Answer >
True dinosaurs were not swimmers. There were a number of very large aquatic reptiles that lived during the age of the dinosaur, but they were not technically dinosaurs. These creatures belonged to one of several other groups, such as ichthyosaurs, plesiosaurs and mosasaurs, which were types of marine reptiles.Full Answer >
There is evidence that dinosaurs did not have a single, uniform and universal diet but rather a wide variety of dietary habits, with evidence supporting the idea that carnivorous, herbivorous and omnivorous species all existed. Different feeding styles were also likely, with some carnivorous species hunting prey such as mammals and small reptiles, while other carnivores may have been opportunistic carrion scavengers. There was likely even a good range of dietary variety amongst the herbivorous dinosaurs, which may have made up the majority of all dinosaur species.Full Answer >
There is not sufficient proof as to why dinosaurs went extinct, but experts believe it is related to geological events, diseases, climate change and lack of plant life for sustenance. The last known dinosaurs, according to their fossils, existed about 65 million years ago.Full Answer >