Was there really an ice atmosphere during the prehistoric era? and also a much higher concentration of oxygen?

Question

because i am pretty sure that there was a higher concentration of oxygen. much like in hyperbaric chambers... which is why all animals were so big.. if there was such a concentration of oxygen today we would prolly be 10 foot tall... but about the ice atmosphere? i mean its enough dinosaurs got to be giant because of the oxygen, but they also were better protected against the sun's UV rays because of the ice layer in the atmosphere.. this is an outrage if its true

Answer 1

Nope, prehistoric oxygen levels were not higher than today's level.  At most the variance from the current 21 percent (oxygen in the earth's atmosphere) would be only about two percent.  Granted, there was quite a rise in oxygen levels just prior to the Cambrian Explosion which may have helped trigger the increase and rapid diversification of early lifeforms.  However, the current level of oxygen is just about the same as the highest prehistoric level.  

For more info, go to:

http://web.missouri.edu/~news/releases/l...

I am not aware of any information regarding a layer of ice in the prehistoric atmosphere---sorry.

Answer 2

There was a much larger amount of oxygen in the air yes, bcos there was lots of plants that produced oxygen and nothing destroyed  them like we do. dont know about the ice atmosphere though.

Rob