Oxygen and the Cambrian: in the pre-Cambrian (Evolution)

by dhw, Monday, October 17, 2022, 13:44 (551 days ago) @ David Turell

QUOTES (with dhw's bolds):

"Oxygen levels in the Earth's atmosphere are likely to have "fluctuated wildly" 1 billion years ago, creating conditions that could have accelerated the development of early animal life, according to new research."
 
"What is uncertain is what happened during the second stage, in a time known as the Neoproterozoic Era, which started about 1 billion years ago and lasted for around 500 million years, during which time early forms of animal life emerged. 

"Fossilized traces of early animals—known as Ediacaran biota, multi-celled organisms that required oxygen —have been found in sedimentary rocks that are 541 to 635 million years old. 

"This periodic change in environmental conditions would have produced evolutionary pressures where some life forms may have become extinct and new ones could emerge." 

"It has been proposed in ecological theory that when you have a habitable space that is expanding and contracting, this can support rapid changes to the diversity of biological life. (

"These expanded habitable spaces would have lasted for millions of years, giving plenty of time for ecosystems to develop." (DAVID’s bold)

DAVID: Early life had little if any oxygen to use. The second bold notes ecosystems had to develop.

The quotes all seem to me to create a unified picture: quite clearly, oxygen was an all-important factor in the evolution of new species. Early forms of animal life emerged before the Cambrian Explosion, but fluctuations could have accelerated their development as well as causing many comings and goings of species – and hence of ecosystems. An ecosystem is simply a collection of plants and animals in a particular area. It doesn’t “have to develop” – it develops, and it changes or disappears when for whatever reason the interrelationships change their balance. These changes can occur rapidly, but if environmental conditions (here the emphasis is on oxygen) remain stable, then of course ecosystems can develop. I don’t know if the article takes into account the theory that the transition from Ediacaran to Cambrian fauna lasted for 410,000 years, but I would still propose that if this period was long enough for your God to have produced the diversity, it would also have been long enough for the thousands and thousands of generations of intelligent organisms to do the same. And over the subsequent millions of years, and with the expansion of habitable places, of course there was plenty of time for species to develop new ecosystems.