New Oxygen research; abundance and Cambrian (Introduction)

by David Turell , Monday, May 06, 2019, 21:15 (2028 days ago) @ David Turell
edited by David Turell, Monday, May 06, 2019, 21:26

A study from Siberian Cambrian rock layers shows the relationship of atmospheric oxygen levels to new species development:

https://phys.org/news/2019-05-oxygen-linked-boom-early-animal.html

"Extreme fluctuations in atmospheric oxygen levels corresponded with evolutionary surges and extinctions in animal biodiversity during the Cambrian explosion, finds new study led by UCL and the University of Leeds.

"The Cambrian explosion was a crucial period of rapid evolution in complex animals that began roughly 540 million years ago. The trigger for this fundamental phase in the early history of animal life is a subject of ongoing biological debate.

"The study, published today in Nature Geoscience by scientists from the UK, China and Russia, gives strong support to the theory that oxygen content in the atmosphere was a major controlling factor in animal evolution. (my bold)

"The study is the first to show that during the Cambrian explosion there was significant correlation between surges in oxygen levels and bursts in animal evolution and biodiversity, as well as extinction events during periods of low oxygen.

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"By analysing the carbon and sulphur isotopes found in ancient rocks, we are able to trace oxygen variations in Earth's atmosphere and shallow oceans during the Cambrian Explosion. When compared to fossilised animals from the same time we can clearly see that evolutionary radiations follow a pattern of 'boom and bust' in tandem with the oxygen levels.

"'This strongly suggests oxygen played a vital role in the emergence of early animal life."
Study co-author Professor Graham Shields from UCL Earth Sciences, said: "This is the first study to show clearly that our earliest animal ancestors experienced a series of evolutionary radiations and bottlenecks caused by extreme changes in atmospheric oxygen levels. (my bold)

"'The result was a veritable explosion of new animal forms during more than 13 million years of the Cambrian Period. In that time, Earth went from being populated by simple, single-celled and immobile organisms to hosting the wonderful variety of intricate, energetic life forms we see today."

"The team analysed the carbon and sulphur isotopes from marine carbonate samples collected from sections along the Aldan and Lena rivers in Siberia. During the time of the Cambrian explosion this area would have been a shallow sea and the home for the majority of animal life on Earth.

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"'The Siberian Platform gives us a unique window into early marine ecosystems. This area contains over half of all currently known fossilised diversity from the Cambrian explosion.

"'Combining our isotope measurements with a mathematical model lets us track the pulses of carbon and sulphur entering the sediments in this critical evolutionary cradle. Our model uses this information to estimate the global balance of oxygen production and destruction, giving us new insight into how oxygen shaped the life we have on the planet today."

Comment: The oxygen levels were very important factors in allowing the diversification of new forms, but there is an underlying evolutionary driving mechanism which is the real cause of the new animals. Note my bolds about oxygen which tends to blur this point . The final bold above makes the point of how sloppy the authors have been in describing the role of oxygen. Oxygen allows the newly designed form to appear, but does not initiate anything. Again, a Darwinism slant in the reporting.