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 in Dinosaurs
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 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 >
There are some animals on earth that can be traced back to the Mesozoic Era when dinosaurs walked the earth; these animals include monotremes such as the duckbill platypus, reptiles such as the crocodilians and sea creatures such as the sea urchin. For the most part, the animals that are alive today have made evolutionary changes from the forms they had when dinosaurs were alive. For example, though the event that caused dinosaurs to die out also killed many other reptile species, several surviving reptile species have direct ancestors from that era, including the crocodilians, which are smaller than their Mesozoic ancestors.Full Answer >
There are multiple theories as to why dinosaurs died out, such as asteroid impact, volcanic activity, and climate change. There are many theories because none has been proven to be 100 percent certain as the reason for the dinosaurs’ demise.Full Answer >