Hyperactive magnetic field may have led to one of Earth’s major extinctions

[HuckleB]

http://www.sciencemag.org/news/2016/02/hyperactive-magnetic-field-may-have-led-one-earth-s-major-extinctions

"Rapid reversals of Earth’s magnetic field 550 million years ago destroyed a large part of the ozone layer and let in a flood of UV radiation, devastating the unusual creatures of the so-called Ediacaran Period and triggering an evolutionary flight from light that led to the Cambrian explosion of animal groups. That’s the conclusion of a new study, which proposes a connection between hyperactive field reversals and this crucial moment in the evolution of life.

The Kotlinian Crisis, as it is known, saw widespread extinction and put an end to the Ediacaran Period. During this time, large (up to meter-sized) soft-bodied organisms, often shaped like discs or fronds, had lived on or in shallow horizontal burrows beneath thick mats of bacteria which, unlike today, coated the sea floor. The slimy mats acted as a barrier between the water above and the sediments below, preventing oxygen from reaching under the sea floor and making it largely uninhabitable.

The Ediacaran gave way to the Cambrian explosion, 542 million years ago: the rapid emergence of new species with complex body plans, hard parts for defense, and sophisticated eyes. Burrowing also became more common and varied, which broke down the once-widespread bacterial mats, allowing oxygen into the seafloor to form a newly-hospitable space for living.

Scientists have long argued over what caused the Cambrian explosion in the first place. Potential explanations have included rising levels of atmospheric oxygen due to photosynthesis, allowing for the development of more complex animals; the rise in carnivorous species and new predatory tactics, such as the flat and segmented, armor-crushing creatures known as anomalocaridids; and the breakup of the super-continent Rodinia, which may have created new ecological niches and isolated populations as the continents drifted apart.

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Very interesting!

[saturnsring]

1. cool stuff thanks for posting. unfortunately since this isnt about circumcision or benevelent

sexism or w.p. it will probably get few replies