Friday, August 18, 2017

NEW RESEARCH REVEALS THE PERIOD IN WHICH THE FIRST ANIMALS APPEARED

Over half a billion years ago Earth experienced one of its largest ice ages that, according to the  latest research, most likely gave complex life its beginning. The research led by Australian National University (ANU) used preserved hydrocarbon biomarkers to find the exact timing of when complex photosynthesising organisms (Archaeplastida) first appeared on Earth. The molecules were found trapped inside sedimentary rocks from the Australian outback and they hint at a global algal bloom that came after the ice's melting and began the base for a biological revolution.

"These molecules tell us that it really became interesting 650 million years ago," said lead researcher Jochen Brocks from the ANU. "It was a revolution of ecosystems, it was the rise of algae."

When a large species of microbial predator began swallowing up cyanobacteria without digesting them, an extraordinary union was formed. This occurred approximately one to two billion years ago and gave rise to the world's first eukaryotes. Later, through the measurement of the ratios of the various molecules, researchers gained a more evident idea of the diversity and size of algal populations.

The research team discovered more diversity and an abundance of the Archaeplastida that occurred at the same time as a gap between two important climate events in Earth's history, the Sturtian and Marinoan 'snowball Earth' glaciations, around 659 to 645 million years ago. The glaciations occurred during the Earth's Cryogenian period. Researchers believe that a flood of chemicals (eg. phosphates) released from the weathered rocks lessened the competition for resources and thus created a population explosion that allowed evolution to persevere.

Read more about this fascinating story at: http://www.sciencealert.com/this-groundbreaking-period-in-earth-s-history-gave-rise-to-the-first-animals

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