Friday, April 20, 2012

It's Baaaaack: The Warm Little Pond

Even in evolution, what goes around comes around. Remember when Darwin posited his “warm little pond” thought experiment. “But if (and oh what a big if) we could conceive in some warm little pond …” So began the homily. Realizing the absurdity Crick switched the narrative to extra terrestrials. That’s where those unlikely seeds of life came. Then it was comets, and then it was deep sea hydrothermal vents. One way to avoid criticism is to keep switching the theory. But what happens when you run out of ideas? No problem, just start over. Of course you must disguise the shell game with newer, more complicated sounding jargon. And so we present, without further ado, “Inland geothermal systems,” a.k.a., warm little ponds:

All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energy-dependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the “hatcheries” of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K+, Zn2+, Mn2+, and phosphate. Thus, protocells must have evolved in habitats with a high K+/Na+ ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO2-dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K+, Zn2+, and phosphorous compounds.

And the evolutionists even have a new method: “Phylogenomic scrutiny.” I have no idea what that means.

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