Has all evolution been forward in it's path?

Has any life form on our planet ever evolve backwards to a simpler life form? If not, why not? If no logic was involved. The atmosphere at the time of the first spark of life could not sustain animal life due to carbon dioxide and volcanic ash. A plants primary role is to consume carbon dioxide and give off oxygen as waste, this sounds as if it was planned out. Did plants clean the air to allow animal life to live on land, or was it another random lucky accident? I am doing an essay on the creation of life and need thoughts on both sides, evolution and creationism.
Asked Nov 18, 2013

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