Aconcagua
The Paleozoic Era
For some reason, there was a “life boom” 550 Ma ago and water was filled with invertebrates, especially arthropods, whose hard covers fossilized and were preserved in time in the sediments.
Fish, the first vertebrates, were already abundant by mid-Paleozoic. Some fresh-water species which lived in temporary puddles had to adapt themselves to stay there even in times of droughts. These animals slowly developed their gills into lungs and their fins into legs and became amphibians.
Then, a special kind of amphibians evolved, giving birth to a new group of animals which did no longer depend on water for survival: the reptiles.
Some 300 Ma, all the emerged landmass in the planet formed one “supercontinent”, known as Pangaea (or Pangea.) This “supercontinent” comprised two other continents: Laurasia to the north and Gondwana to the south.
Laurasia was made up of North America, Europe and Asia. Gondwana, on the other hand, included South America, Africa, Australia, Antarctica and India.
This period ended with a worldwide catastrophe, of unknown origin, which terminated 90% of the species existing at the moment.
