For quite a long time, scientists have been trying to understand how life on Earth evolved, and how it jumped from the bacterial domination to a bit more complex life forms. Recently, a team of researchers from the Australian National University claims to have discovered the trigger of this major transition, and of the beginning of the animal domination.
Algae are responsible with the evolutionary boom
Researchers gathered all their findings in a study, published in the journal Nature. They suggest the algae expansion was the moment when life switched from being mostly bacterial based to being dominated by more biologically complex creatures.
The process started about 700 million years ago. Back then, our planet suffered an event nicknamed ‘Snowball Earth’. For about 50 million years, the entire world was covered in ice. Even at the equator, the ocean was frozen up to a depth of two kilometers. When all this melted, all the nutrients reached the waters of the ocean, which permanently affected Earth’s ecosystem.
Traces of ancient organisms found in rocks showed scientists how life evolved on Earth
Researchers analyzed several sedimentary rocks originating from that period, which they had collected from Central Australia. Then, they ground these rocks into a powder, and looked at traces of ancient organism molecules trapped inside. From these molecules, they could put together the evolution of life after Snowball Earth.
These molecules indicated that many nutrients got dumped into the ocean as the huge mass of ice melted. This is what propelled the rise of algae, which contributed to the development of food chains and the creation of more diverse ecosystems.
The algae spread so rapidly as the oceans got so rich in nutrients. Also, the global meltdown reduced the temperatures all over the world, and the environment became more hospitable for algae. These organisms lie at the base of the food chain. They brought an immense input of energy, which propelled the development of complex ecosystems.
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