THE cherished assumption that life emerged in the oceans has been thrown into doubt. New research shows that primitive cellular membranes assemble more easily in freshwater than in salt water. So although the oldest known fossil organisms were ocean dwellers, life may actually have developed in freshwater ponds.
Most theories on the origin of cellular life presume that the first step was the formation of a spherical membrane called a vesicle that could enclose self-replicating chemical chains—the ancestors of modern DNA. The idea is that the ingredients for simple membranes were all present on the early Earth, and at some…
