Transcript: Life forms on Earth can exist and thrive in extreme chemical conditions corresponding to acid or base. Acidophiles can thrive in conditions where the pH is less than five. That's similar to sulfuric acid. Examples include the sulfur pots in Yellowstone Park, volcanic soils, and of course the gastric fluid in the human stomach. At the opposite extreme are alkaliphiles which can exist and thrive at pHs greater than nine. Examples include soda lakes in Africa and soils that are rich in carbonates.