Quote:
Originally Posted by jlhredshift
Many "popular" books and even some textbooks have made similar statements, albeit it is probably dated material by now.
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OK - fair enough ...
I have some outdated textbooks and reference books myself - excellent resources for historical background, etc, but not always reliable for conclusions in the light of later information ...
Quote:
Give us your thoughts, please. (seriously)
John
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Well,
AndrewJ's statement raises two issues:
1 - the timing of the establishment of the ozone layer; and
2 - whether the ozone layer (or even atmospheric oxygen) was the critical factor in the timing of the emergence of land-based life ...
but neither really address Swift's OP issue - "a possible trigger for the Cambrian Explosion" - which also has multiple discussion paths:
1 - the merits or otherwise of the linked article and associated study;
2 - the historical and contemporary importance of the Cambrian Explosion within the broader evolutionary trends;
3 - possible triggers for mass speciation events ...
So, I'm inclined to wait for
Swift to clarify the OP intent or desired direction ...
rather than find myself hauled over hot coals for hijacking ...