Now that we know how the dinosaurs died out, focus is being put on how dinosaurs ended up on the top of the food chain.
Proceedings of the National Academy of Sciences published this week new research on the events that may have been a blessing for the ‘saurs. Around 206 million years ago was the end-Triassic extinction event, which wiped out approximately 76% of all species on Earth, though the event isn’t as widely known as the KT extinction that killed the dinosaurs. This event also has less theories as to why it happened.
The new research in Proceedings suggests that volcanic activity was the culprit. The North American and African plates pulled away from each other, breaking apart Pangaea and allowing magma to reach the surface. With it came carbon-12, an isotope normally released with volcanoes. Chemical plant fossils from this time period have higher than normal carbon-12. This gas, along with other greenhouse gases, altered the Earth’s temperatures. Other chemicals released from the activity altered the pH of the oceans and of rain, which lead to the demise of sea life and plants.
The biggest casualty of the event were the crurotarsans, which were alligator-like vertebrates. Most of them went extinct because of this event, though the dinosaurs did not. Why one and not the other survived is unknown, but after the end-Triassic extinction, there was little competition for resources, and dinosaurs quickly filled in the gaps left behind.
Most dinosaurs of the Triassic period were small, such as the dimetrodon, but the Jurassic period was when they took full advantage of their new supply of resources. Allosaurus, diplodocus, and archaeopteryx were all representative dinosaurs of the Jurassic.
http://www.ucmp.berkeley.edu/mesozoic/triassic/triassic.html
http://www.britannica.com/EBchecked/topic/1523109/end-Triassic-extinction
http://www.livescience.com/animals/how-dinosaurs-ruled-earth-100322.html
i want a T-Rex for a pet!
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