#4 of 5 short stories on the Origin of Life - The Singularity (x 3)

According to Wikipedia, “the singularity, is a hypothetical moment in time when artificial intelligence will have progressed to the point of a greater-than-human intelligence, radically changing civilization.” Whether a technological singularity is going to happen in the near future or the distant future is unknown and it may in fact, never happen. But the concept that an evolving system such as artificial intelligence, could produce something that is greater than the sum of its parts is already evident in nature. For instance, humans have language systems that are far more complex than the communications of our closest relatives such as chimps, bonobos and orangutans. Language provides a new platform for development, as information can be exchanged on a level that goes beyond genetic transfer of information from parent to offspring.

Cellular life

The three cell architectures

Another example of a singularity-like event is at the very beginning of cellular life. And this singularity -- the invention of the cell -- might have happened three separate times.

All life that we know of is related and descended from a common ancestor. The last universal common ancestor (L.U.C.A.) gave rise  to all 3 domains of life we have today:  Bacteria, Eukarya, and Archaea.  LUCA might have been similar to a modern bacterial cell plan, just more simple -- a so-called protocell, that once able to grow and divide gave rise to all life on planet Earth.  But another intriguing possibility is that the LUCA was not simple and it was not cellular.

Network life

This idea comes from Carl Woese, who suggested that a pre-cellular network spawned the 3 known cell architectures of Bacteria, Eukarya, and Archaea – and spawned these 3 cell types at different times. The idea is intriguing, because instead of relying on all of the complexity of life coming from a single, simple package of replicating material, it implies that pre-cellular life was a complex network of biochemical ideas. In this model, there was an ecosystem of biochemical exchange, with a tremendous diversity small packets of information exchange through what we now call horizontal gene transfer (HGT). There were no parent cells, no offspring and no linear form of descent.

LUCA was also likely to rely heavily on RNA for information and activity, with the invention of the language of translation (RNA -> Protein) a critical first step in the origin of life. But the next critical step was to spawn a cell from this network – the first bacterial cell that was also the first isolated, self-replicating form of life. Woese argues that bacteria, archaea and eukaryotic cells are so different from one another, that they must’ve spawned from the pre-cellular living network at different times.

Fungal mycelia are a modern form of networked life

Is there non-cellular, network life today?
There is no evidence that the type of biochemically diverse network that Woese describes giving rise to cellular life still exists today. But biochemists can perform in vitro evolution experiments to test how chemical systems can evolve outside of cells--and they do. And interestingly, many forms of life today mix cellular life with a network of material exchange: Mycorrhizal connections allow metabolic exchange between fungi and plants, Plasmodial slime molds can forgo the limitations of cell division, forming extensive branching structures with a shared cytoplasm. And many bacteria form tubes and vesicles that connect neighboring cells.  This cellular/network mix is also found in some of the thermophilic organisms that may be most similar to the very first cells.  

s of cells when nutrients are scare, and form long, branching cytoplasmic networks without cellular separation and finally many bacteria form networks of membrane extensions through

Next up is the last installment of origin stories #5 To catch a predator