> Sirius, thank you for the geology perspective on
What do you mean "geology perspective?"
> If "oxygen levels have been gradually decreasing
> at about 0.7% over the last 800,000 years", that
> probably means a relatively stable atmospheric
> mixture, with nearly no impact on evolution.
Exactly. You'd expect a drastically changing atmosphere as was the case in the Cambrian to have far more opportunities for evolution especially as the change from a reducing atmosphere poisoned off much of the life that already existed and opened up new niches for organisms to take advantage of. In a more stable atmosphere other factors became more important as drivers of evolution such as climate and predation.
> temperature does not seem to have much impact on
> evolution among mammals?
Let's see......Wooly Mammoth vs modern hairless elephant.
Snowshoe hare vs rabbit
Lynx vs leopard
Polar bear vs black bear
Musk ox vs bison
arctic fox vs .....fox
Harp seal vs Monk seal
Yes, I think you must be right there that temperature has little impact on the evolution of mammals.
Thus mutation and
> environmental selection were the main drivers of
> mammalian speciation in the last million or two
Mutation and environmental selection are always among the main drivers of evolution.
> About the geology billions, what is the latest on
> the missing billion years worth of layers in the
> Grand Canyon?
> If a billion could be removed by erosion, could
> that be in one event? And could a supposed billion
> be laid down (moved from elsewhere) in one event?
What do you think? Maybe something to do with how the continents were moving?
> Could geology suffer from a Manetho kind of error,
> by stringing out layers that were actually
> And if so, could biology also suffer from the
> same, and some of its own, high chronology
What are high chronology assumptions? Can you give an example?
Edited 1 time(s). Last edit at 01-Oct-21 18:18 by Sirius7237.