Evolution of multi-cellular complex animal – A new idea

Evolution of multi-cellular complex animal is always an interesting topic. Currently scientists thought that the explosion of complex life was fuelled by oxygen boom. At Mistaken Point in Newfoundland, Canada, the oldest fossils of the enigmatic flat, soft-bodied Ediacara-period fauna spread across the sea floor within five million years after oxygen permeated the waters.

Guy Narbonne of Queen’s University in Kingston, Ontario, Canada says, “The chain of events started with a Glaciation that covered much of the planet with thick ice sheets until 580 million years ago.” At the end of the Glaciation, the rocks change color within a few meters diplaying differences in mineral concentrations, such as iron. The iron compounds reveal a rapid rise in oxygen to at least 15% of today’s level, he says.

Narbonne believes the big thaw triggered a boom of Phytoplankton that pumped oxygen into the air, which quickly permeated the sea. Microbes had dominated the planet for billions of years, but oxygen changed the rules and put evolution on fast-forward. The first Ediacara fossils date from 575 million years ago, and 10 million years later complex communities of filter-feeders had spread over the sea floor. After that, animals evolved mobility by 555 million years ago, and the Cambrian explosion of evolutionary diversity began 542 million years ago.

Ref.: Science (DOI: 10.1126/science/1135013)

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