Questão 11 - UEA - SIS 2ª Etapa 2017

Leia o texto para responder à questão.

 

Was the Amazon once an ocean?

  The Amazon rainforest is a valuable source of biodiversity, containing 10% of the planet’s species in its 6.7 million square kilometers. How it got to be that way has been highly disputed for decades. Now, a new study suggests that a large section of the forest was twice flooded by the Caribbean Sea more than 10 million years ago, creating a short-lived inland sea that jump-started the evolution of new species. But the new evidence still                  scientists on the other side of the debate.

  Researchers generally agree that parts of the Amazon were once under water, but they don’t agree on where the water came from. Those in the “river camp” argue that freshwater streaming down from the rising Andes divided the land below, dividing plants and animals into isolated groups that later turned into new species. The fastgrowing mountains also created microclimates at different elevations, sparking speciation and funnelling new plants and animals into the Amazon basin. However, when marine microorganisms were discovered in Amazonian sediments in the 1990s, some scientists hypothesized that the forest was once inundated by an ocean, which created new species as forest inhabitants quickly adapted to the flood.

(Lizzie Wade. www.sciencemag.org, 03.05.2017. Adaptado.)

Sobre a hipótese de que partes da Amazônia já estiveram submersas, os pesquisadores em geral