LIFE FROM SCUM
What mystery pervades a well!
That water lives so far—...
Like looking every time you please
In an abyss's face! (1400)
Whether bacterial or nucleated, the units of life are cells. All visible organisms are composed of nucleated cells, and, as we have seen, the first nucleated cell evolved by bacterial cell merger. But how did that elusive unit, the parent of all Earth life, originate? What accounts for the beginning of the ur-cell? How did the very first bacterial cell originate? This question is exactly equivalent to the question "How did life originate?" To appreciate SET, which only recombines, merges, and integrates exceedingly diverse bacteria, we first have to understand where these diverse bacteria came from. In short, we need to try to understand life from scum.
In search of the ecological setting of the earliest cells on Earth, every few years my students and I make a pilgrimage to San Quintin Bay, in Baja California Norte, Mexico.We seek the shifting shores of Laguna Figueroa, a lagooned complex festooned with salt flats.Here we find laminated, brightly striped sediments underlain by gelatinous mud. These colorful seaside expanses, called "microbial mats,"