I will post it here, for the record, and I will post it to ask science here at Voat!

I was wondering if petroleum is like some kind of blood for the earth, does it has any real purpose in nature?

In the past people has burned mummies as a form of fuel. Today we burn petroleum which I was taught is dead animals and plants from the past. Is it? or is it a form of blood that fuels life on earth, like soil fuels plants to grow, or like air fuels in our lungs? I understand we consider it to be toxic because we can't drink it. But if it harvest some kinds of bacteria, that means it's edible for some life forms. Aren't we burning one "element" needed to harvest life on earth without knowing?