re: #101 FurryOldGuyJeans

Another good example of that is the lung. Early ID proponents claimed the mammalian lung was irreduceably complex, and the oxygenation of blood couldn’t have co-evolved with a lung system bit by bit, since the circulatory suystem and the lung system would have to emerge fully formed to be of any use to each other

But then, of course, it was discovered that the early lung was originally a “flotation bladder” organ used by primitive proto-fish to stay afloat and to go up and down in the water — it had nothing to do with oxygenizing the blood, at first. But little by little, this “side effect” become predominant and allowed the creatures to get oxygen from the air, as opposed from the water — voila, we get land creatures.