The earliest oxygen-breathing bacteria (Evolution)

by David Turell , Saturday, October 22, 2011, 23:23 (4589 days ago) @ dhw

Here we are told that aerobic (= oxygen-dependent) bacteria on land broke down the pyrite, and this released acid into the oceans. Why then do the researchers argue that our ancestors started off in acidic water? Why weren’t the preceding oxygen-dependent land bacteria our ancestors?

Not silly. Misunderstood. First were the cyanobacteria which used a metabolism that created some oxygen in the atmosphere, which did not have oxygen at first. Once enough oxygen appeared than organisms could appear that used oxygen. The acidic water is where the researchers found the organism, presently. they think it needed the water and never changed.