The Science of Existence (82) Abiogenesis


Whenever a new planetary system is made, these kinds of things should go on. This potential to make organics and then dump them on the surfaces of any planet is probably a universal process. ~ American astrophysicist Scott Sandford

Abiogenesis is the study of how organic life arises from inorganic matter.

For life to begin and sustain, 3 means have to arise: 1) self-contained cells (containment); 2) usable energy to produce proteins (metabolism); and 3) replication (reproduction). Any decent hypothesis of life’s origin must account for all these facets.

The requirements for life’s emergence seem to present a chicken-or-egg problem of which came first: metabolism or replication. While scientific consensus has yet to comfortably square that circle, the answer is fairly certain.

Inorganic energy provided the impetus to put together the organic building blocks that resulted in biosynthesis and nucleobase production. The complexity of both are equivalent, and both are needed.

Sequence is not the issue. The trickiest aspect is not of molecular combinations. Instead, it is the synchrony required for all the ingredients to functionally cohere; for metabolic energy to consistently be applied within a cell where and how required to sustain life, and for RNA to become the basis for reliable memory in protein production.

To simply say that “life happens,” or that energetic pathways are dictated by economy, misses the big picture as well as the myriad of details.

No matter how minute an organism may be, or how elementary it may appear at first glance, it is nevertheless infinitely more complex than a simple solution of organic substances. ~ Alexander Oparin

Aside from the biochemical substrates and processes, there must be a natural force of coherence that begets life. Finding favor in physics and chemistry is, by itself, inadequate.

The underlying problem is complexity. Although we have no idea of the minimal complexity of a living organism, it is likely to be very high. It could be that some sort of complexifying principle operates in Nature, serving to drive a chaotic mix of chemicals on a fast track to a primitive microbe. ~ Paul Davies

Above all, the macromolecules that make for the principle players in cellular life must stably self-assemble yet have the ready flexibility for different conformations to act as information storage. (A misstatement by abbreviation is made here. Matter may store information, but matter cannot use information. Information is purely conceptual, and so immaterial. As the show called Nature is made of matter, essential concepts such as information are portrayed materially – whence brains and accoutrements which comprise an ‘intelligence’ physiology. Do not confuse appearance with actuality–the very mistake matterist scientists blithely make. Information implies mentation – a mind at work.) And all this must be achievable with a mere modicum of energy. These requirements highlight how even the simplest life itself possesses an inherent sophistication that places it well beyond random chance.

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Just as many people have been speaking prose all their lives without realizing it, many organic chemists of the 19th and the first half of the 20th century were prebiotic chemists without realizing it. ~ English chemist Leslie Orgel

Modern organic chemistry began with German chemist Friedrich Wöhler accidentally synthesizing urea in 1828. Russian chemist Alexander Butlerov discovered the formose reaction in 1861, forming sugars from formaldehyde. This remains a cornerstone of prebiotic chemistry. These and other early experiments into synthesizing biochemicals were oriented toward practical applications, without interest in the origin of life.

The first to have such an interest was American chemist Stanley Miller, who in 1953 reduced amino acids from a brew of heated CH4, NH3, H2O, and H2 subjected to an electrical discharge. In selecting his prebiotic compounds, Miller aimed to recreate the chemical conditions of early Earth.

Miller’s assumptions were mistaken, as were many of the surmises that followed in his wake. Miller began what became a continuing quest by would-be Dr. Frankensteins to create life in a flask.

Since we know very little about the availability of starting materials on the primitive Earth or about the physical conditions at the site where life began, it is often difficult to decide whether or not a synthesis is plausibly prebiotic. Not surprisingly, claims of the type “my synthesis is more prebiotic than yours” are common. ~ Leslie Orgel

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From the 1960s, the idea of abiogenesis via spontaneously assembling proteins was gradually displaced by hypotheses emphasizing replication: life’s onset via RNA. This notion first developed when life was presumed to emerge from primordial pools, with RNA emerging by dint of fortuitous biochemical combination. Though the focus shifted, the axiom of life beginning via chemical elixir remained.

Another story of life’s origin starts with fool’s gold in the hydrothermal deep, arguing metabolism-first. There are similar scenarios with slightly different emphases.

Then there is the possibility that life on Earth came from outer space: a concept called panspermia. Demonstrating the natural force of coherence, organic molecules readily form where chemistry instructs they should not. One panspermia scenario has life on Mars coming here.