Cambrian Explosion: role of continental drift (Introduction)

by David Turell @, Friday, February 19, 2016, 15:18 (1499 days ago) @ David Turell

Another far-out proposal that the continents drifted toward the Equator and produced shallow areas where life could have diversified:

http://phys.org/news/2016-02-great-secrets-earth-evolution.html

"Around 520 million years ago, a wide variety of animals burst onto the evolutionary scene in an event known as the Cambrian explosion. In perhaps as few as 10 million years, marine animals evolved most of the basic body forms that we observe in modern groups.

"The event has sparked fierce debate all the way back to Darwin. Some paleontologists see the Cambrian explosion as a real, astonishing episode of unprecedented, fast evolution. Others suggest it is a false artifact of an unreliable fossil record.

"Now work published in the American Journal of Science shows that these competing theories can be unified by the geography of Cambrian Earth, as it underwent a wholesale lurch that clustered most of Earth's continents around the equator.

"Co-author Dr Timothy Raub of the Department of Earth and Environmental Sciences at the University of St Andrews said: "In a nutshell both camps were right. The particular locations of Cambrian continents relative to each other was special in a way that supercharged animal speciation while preserving an unusually good record of those early fossils."

***

"The paper suggests that about 520 million years ago a lurch of more than 60 degrees moved most continents from polar to tropical latitudes. For reasons that are still debated, biological diversity reaches a global peak around the equator and tapers off closer to the poles. This early Cambrian rotation therefore would have dramatically increased shallow coastal area in Earth's biodiversity hotspot.

"As another consequence of true polar wander, continents moving towards the equator are flooded by hundreds of metres of sea level rise, as they encounter the great bulge of water caused by Earth's daily spin. This flooding would have increased fossil preservation, but it also would have opened up new habitats for rapid diversification, in particular vast continental seaways rife with previously unexplored ecological niches."

Comment: Another theory that skips the issue of what drove the genetic explosion of information that created the complex organisms from very simple ones.


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