Haven't we all been fascinated by dinosaurs as kids? But long before dinosaurs roamed our Earth, there were other creatures that came and went.
Paleontologists (scientists who study fossils) believe that ugly reptile-like creatures known as Pareiasaurs were the rulers of the earth, well before dinosaurs arrived on the scene.
What Are Paraeiasaurs?
Imagine huge barrel-shaped creatures with chunky arms and legs, small heads and teeth, and having bony knobs covering their entire body and face.
The Paraeiasaurs were probably the first animals to evolve legs that supported their bodies. Legs are the most efficient way to move from one place to another, making it easy for these creatures to travel in search of food. They are believed to have lived between 1 to 2 million years ago during the Permian period when all the continents were connected.
These creatures are often known as the 'ugliest fossil reptiles' ever found by the scientific community. Pareiasaurs are heavy-weight herbivores that once roamed Russia, Germany, Scotland, China, South Africa and even South America.
For a long time, scientists believed that the Paraeiasaurs found in each region were distinct. But recent studies confirm that the fossils share a lot of similarities. This conclusion seems to suggest that these heavy-weight vegetarians wandered around the globe despite their awkward movement. Pareiasaurs are believed to have become extinct during the end of the Permian era that wiped out more than 96% of the species on the planet.
Mass extinctions are periods in Earth's history when an abnormally large number of species die out simultaneously or within a limited time frame. Usually, mass extinctions are not single events but occur over a period of several years following a huge natural disaster, such as a meteor or volcanic eruption. This, in turn, sets off a chain of events that wipes out most life forms.
Based on studies, scientists believe that our planet has been rocked by at least five big mass extinction events, though many smaller scale extinctions have occurred that show up in fossil records. With each extinction, several species disappear and gives way to a fresh burst of life on earth. The big extinction events are:
- Ordovician extinction - It was a time when the earth was dominated by sea creatures such as trilobites, brachiopods, and graptolites. They were drastically reduced in number during the die out.
- In the late Devonian mass extinction, three-quarters of all species on Earth died out, due to a series of events that spanned over several million. Life in the shallow seas was the worst affected.
- The Permian mass extinction also nicknamed The Great Dying was a die-out when a staggering 96% of species were lost. All life on Earth today is descended from the 4% of species that survived.
- Triassic-Jurassic mass extinction is believed to have occurred during the final 18 million years of the Triassic period. Climate change, volcanic eruptions, and an asteroid impact have all been blamed for the loss of life during this event.
- Cretaceous-Tertiary mass extinction also known as the K/T extinction is thought to have caused the death of the dinosaurs. However, many other organisms perished at the end of the Cretaceous period including ammonites, many flowering plants and the last of the pterosaurs.