My original hypothesis, that freshwater species had replenished the upper ocean, turned out to be false. Zooytes had no genes as such, just families of enzymes that re-synthesized each other after cell division, but comparisons of these heritable molecules showed that, rather than rain bringing new life from above, an ocean-dwelling species from a much greater depth had moved steadily closer to the surface, as the Angels’ creations drained oxygen from the water. That wouldn’t have been much of a surprise, if the same techniques hadn’t also shown that several species found in river water were
...more
