NATURAL SELECTION EVOLVED

I have been in the process of writing a book for over ten years. Many bits and pieces of that book have appeared on this bog site as posts. The overall task is turning out to be overwhelming. I cannot seem to get myself out of the primordial pools where scientists are certain life evolved. After an internet research session, I am starting to see some order but not a solid solution. Cosmic chemists named S. L. Miller and H.C. Urey, at the University of Chicago in 1950, conducted what became seminal experiments dealing with cosmic environments. They confined elements and spontaneously generated molecules such as ammonia believed to exist in the earliest environment (free oxygen did not exist at the time) and, metaphorically speaking, hit them with lightening. The results were what we call organic compounds. Further experiments by these and other scientists found hydrogen cyanide, amino acids, and nucleic acids among many, many other compounds. The finding was so profound and had such and impact that creationist started screaming—only God can create life and not a bunch of scientists.

Primordial pools with all these interacting organic compounds in various concentrations and myriad environments became complex stews of chemical molecules including elements leached from the those environments such as sodium, chloride, potassium, phosphorous, calcium and a long, long list of etceteras. The pools changed concentrations of these chemical as water evaporated and rain fell, they changed temperatures not only from the cooling atmosphere but also from day to night, and changed from loss and absorption of volatile chemicals such as carbon dioxide. The addition of carbon dioxide increased the hydrogen concentration while loss of carbon dioxide lowered hydrogen ion concentration; hydrogen is the fickle element, it will jump from compound to compound for the slightest of reason changing the nature of the compounds reaction potentials with which it is affiliated. Carbon dioxide volatilizes and is lost when it is high in the atmosphere it will be absorbed by the water in the pool. Everything that happens follows the rules of chemistry and physics; the same rules we have today. The solubility of carbon dioxide is temperature sensitive, therefore, the concentrations of carbon dioxide changes from day to night establishing a circadian rhythm. The pools could be said to breathe. Again, the creationist scream, only God can create things that breathe.

In the process of researching biological cybernetic, the communications of cells with other cells, I ran into the a number of levels of communications; some would say there are electrical and chemical communications but in truth, nerve impulses are chemically mediated; therefore, in the end, all cell to cell communication in biology is chemical.  The list of chemicals that have to do with some form of biological communication is formidable even when reduced to categories. Although how each functions is not important in this context, what is important is to point out that they are relatively simple compounds. They are monoamines or neurotransmitters, prostaglandins with strong physiological effects, pheromones or chemicals secreted animal that influences the behavior or development of others of the same species, hormones, which chemists divide into steroid and peptide/protein forms. Hormones are substances produced by one tissue and conveyed by the blood or lymph to another to effect physiological activity of another tissue such as growth or metabolism.

I arranged the above list of “communication” molecules is descending ordered by chemical structure. Monoamines are the simplest and are all have a simple amino acid structure.  Prostaglandins all have essentially the same basic structure as well but it is a fatty acid—a chain of 20 carbons including a five carbon ring but with different side groups. Pheromones are chains of carbon atoms with different side groups and types of bonds. Steroid hormones have a common complex polycyclic structure but each has different side groups. Finally, the peptide and protein group of hormones are a bewildering array of over 20 different types of amino acids in chains. Peptides are short chains and proteins are long chains. Scientists have identified 46 peptide/protein hormones know so far.

Except for proteins, “communication molecules” including peptides, are not that complex chemically and I believe could form spontaneously as product of primordial pool dynamics as so eloquently demonstrated by Drs. Miller and Urey. Of course, in primordial pools, they are just random products devoid of function. Because cells exist, in fact because we exist, we know that droplets of primordial pools ended up enclosed in membranes. By random chance, some cells contained a system for capturing the suns energy in a usable chemical form. The process is termed photosynthesis, which we all learned about in grade school, and the chemical form of energy is usually in what scientists refer to as high-energy phosphate bonds. Of interest, is the fact, this process produced all the free oxygen we have in the atmosphere.

Of course, every chemical bond either requires energy to make or requires some energy to break.  When a high-energy bond is broken it transfer its energy to another bond and or releases it as free energy. It seems remote but when you burn a log in the fireplace, you are releasing the suns energy into your living room. Like wise in the body, we digest food, thus,  release the sun’s energy stored in that food one bond at a time and not all at once, like a burning log.

Darwin proposed the theory of the last universal common ancestor (LUCA), the droplet of primordial pool enclosed in a membrane. Scientists now believe with a high degree of certainty that such droplets existed 3.5 to 3.8 billion years ago, especially if we accept the idea that information could pass from cell to cell. The principle implication of this theory, a switch from primordial pools to cells, is that a way to transmit information from generation to generation evolved including the detailed molecular structure of spontaneously formed compounds formed in primordial pools—a Herculean task. To do this a purposeless system involving chemical codes developed—codes required chains of dissimilar subunits such as is found in peptides (changes of a variety of over 20 amino acids), and nucleic acids, chains of four dissimilar bases, such as adenine, which, like amino acids, were products Miller and Urey found after the lightening strike in their Chicago laboratory. None of this was done with purpose, only random chance following the rules of chemistry and physics.

Chains of amino acids could not duplicate themselves but chains of nucleic acids could. The conclusion by scientists was obvious; nucleic acids contained and transmitted information from cell to cell; this is generational transmission. What was not so obvious was nucleic acid chains and did not happen, after cells evolved, but developed before—they developed in primordial pools along with all the other biologically important molecules. In addition, peptides contained information found in daughter cells but, because proteins were not self-duplicating, the information was not transmitted by proteins but by nucleic acids. Thus, the stage was set for one of the most important discoveries in biology; as reveal by DNA/RNA chemists; DNA/RNA could trans-generationally transfer massive amounts of information carried by proteins. The information required to form all the molecules of life, even some of those that nature had spontaneously formed in primitive atmosphere, had to be squeezed through the DNA/RNA keyhole from generation to generation.

DNA/RNA may be the wise old men of evolution, but proteins are the workhorses of biology: structure, membranes, enzymes, transport, transfer, etc. In the form of peptides, they joined monoamines, prostaglandins, pheromones, and steroids in their task of communication between discrete units of bit of primordial pool and pools—thus they were the gossips.

The unknown was and is still, “How useful information found in proteins originated in the chemical chaos in primordial pools and then was put in transmissible form in DNA/RNA?”  No one seems to know. My speculation—and it is pure speculation—is that in the beginning, by random chance, dimer and trimer amino acids randomly formed in a two-step process that served a catalytic function for chemical reactions involve in capture of the sun’s energy in high-energy phosphate bonds—a concatenation of about 300 metabolic steps.  Of course, this was only one of a huge series of reactions extant in the primordial pool. The formation of high-energy bonds would be a way to store and focus the sun’s energy on to a specific chemical reaction. The assistance to any one of the chemical reactions in the series could be minimal; all it would have to do is make it just a little bit easier to form high-energy phosphate bonds—to give slight preference over billions of years.

The first step would have been the formation of covalently bonded random amino acid chains forming a core molecular amino acid chain, a rare, rare one of which served as pro-protease enzymes; a specific amino acid side group could electrostatically bind two specific amino acids, holding them in position thus allowing a covalent peptide bonds to form. As mentioned, amino acids have over twenty different side groups so the possibilities of random paring seem large. Once the bond formed, the product would be released and then the pro-enzyme would await the next binding of two amino acid made available by substrate diffusion. This may sound far fetched, but without getting into binding site configurations and allosteric release mechanisms, this is how scientists have shown how enzymes work. The same random chance mechanism could apply to DNA/RNA but because it is simpler with amino acid than nucleic acids, I chose to use the amino acid chains as the model; for example, it takes three nucleic acids to identify and specify one kind one amino acid. Nonetheless, DNA would eventually have to be involved to be transmissible.

Once a dimer of amino acids aided an energy producing reaction, there would be more focus of energy on the formation of that specific dimer then on others. We could say that reaction was “selected by adaptation”. Because it aided itself, it was self-perpetuating; it was “survival of the fittest”. All the other reactions dealing with DNA or peptide, as in the example, would continue randomly but with less and less substrate, eventually to be lost due to biological parsimony. Cells would absorb water, metabolites, electrolytes, etc as the environment dictated but the DNA and its products reigns supreme.

What I just describe was a fanciful interpretation of what seem to me the fundamentals of evolution of natural selection. Once this is proved, if ever, everything after that still may be of vital interest but would be anti climatic. At worst, it seems to be falsifiable suggestion. 

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