There are many Geological time periods that stand out on their own rights but one among them was bordered and ‘sandwiched’ by two of the worst cataclysms Earth witnessed throughout its history. Behold… the Triassic Period.
Triassic Period is the first of three periods of the Mesozoic Era. Lasting about 52 million years, it kick-started about 252.9 million years ago after the End-Permian Extinction event (The Great Dying) which wiped out about 95% of marine life and 70% of terrestrial species. Evidence of prolonged volcanic activity in the Siberian Traps coinciding with this event shows it was the major cause. This unprecedented release of carbon dioxide into the atmosphere for numerous millennia altered global climate, created anoxic environments, and acidified oceans killing off major ecosystems of the time.
The rest 10% of species that held on, were left with a world without competition. And because mass extinctions are quickly followed by intense diversification of life, the surviving species rapidly adapted to previously occupied niches which were left barren after the extinction event. The Pangea supercontinent which formed during the late Carboniferous period altered the inland climates and became utterly dry. This humongous landmass transformed the beautiful tropical forests into vast grasslands as continuous mountain ranges and other natural barriers restricted moisture and rainfall to the inland. Likewise, the marine niches which plummeted in diversity were also waiting to be occupied. This awoke the dawn of reptiles!
The sudden burst of adaptive radiation favoured animals like the mighty marine reptile Shonisaurus (biggest Ichthyosaur), the semiaquatic Phytosaurs, and the terrestrial chameleon-like bird snouted Drepanosaurus. Our familiar dinosaurs and mammalian ancestors evolved during the Late Triassic and lived in the shadows of these major reptiles.
Things were looking promising for these reptiles until the small geological window of Triassic came to a close in the form of the End-Triassic Extinction Event about 201.3 million years ago. Wiping out about 75% of all species on Earth, the dominating reptiles vanished from the fossil records.
Sandwiched between these two extinction events, the Triassic period sheds light on how life restores itself in a “short” interval despite being met with numerous crises.
The cycle of life moved on as, during the Early Jurassic, these same niches were calling again to be occupied. But this time it was the dinosaurs which replied before the tiny mammals could say “yes”. And it was their time to rule the Earth!
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