While dinosaurs no longer exist today, these massive creatures used to dominate the land over a hundred million years ago.
What Are Dinosaurs?
The term Dinosauria was coined by Sir Richard Owen, an English naturalist, in 1842. The word comes from the Greek word "deinos," which translates to "fearfully great," and sauros, which means "lizard."
Dinosaurs are classified as reptiles. They evolved to become various sizes and shapes later on. These creatures were quite successful during their time, with one reason being their straight back legs that are perpendicular to their bodies. Because of this unique feature, they required less energy for movement compared to other reptiles with a sprawling stance. Their weight was also better supported by the positioning of their lugs under their bodies rather than sticking out to the side.
The earliest known dinosaurs were present during the Triassic period that took place around 200 to 250 million years ago. They then evolved to become different species with unique characteristics.
The biggest dinosaurs, including the Argentinosaurus, Ultrasaurus, Seismosaurus, and Supersaurus, reached more than 30 meters in length and 15 meters in height. On the other hand, the smallest ones, such as the Comphsognathus, were chicken-sized. Most dinosaurs fell in between this size spectrum.
These creatures also had distinctly unique features. Some were bipedal, while others were quadrupedal. Some were fast while others were slow. Others had armor plates, horns, spikes, frills, or crests. There were also some with bumpy and thick skin and even feathers.
Dinosaur Extinction
At present, there are around 700 known extinct dinosaur species. Fossils of dinosaurs have been discovered in all seven continents of the world.
These reptiles dominated the land for roughly 245 million years. Unlike what several people think, not every dinosaur existed at the same geological era. The Stegosaurus, for instance, lived around 150 million years ago in the Late Jurassic Period. On the other hand, the Tyrannosaurus rex existed around 72 million years ago in the Late Cretaceous Period. The Stegosaurus went extinct 66 million years prior to the arrival of the T.rex.
In the Mesozoic Era that covered the Triassic, Jurassic, and Cretaceous eras, non-avian dinosaur species ended up evolving into avian dinosaur species. This avian became the first bird and ended up becoming the forerunner of bird species as a whole.
All non-avian dinosaurs became extinct 66 million years ago. This was when the Cretaceous period ended and it was a time of great tectonic and volcanic activity. While there are several theories regarding the extinction, the most accepted one is that an asteroid impact could have bolstered serious climate change that dinosaurs could not adapt to.
At present, these creatures may live on as birds. All that remains of dinosaurs are fossils and possible birds.
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