Let’s suppose there was a first Last Universal Common Ancestor (LUCA) or a small population of it. How did it overcome deleterious harmful mutations, in order not to go extinct?
M.LYNCH (2003): Although uncertainties remain with respect to the form of the mutational-effect distribution, a great deal of evidence from several sources strongly suggests that the overall effects of mutations are to reduce fitness. Indirect evidence comes from asymmetrical responses to artificial selection on life history traits, suggesting that variance for these traits is maintained by downwardly skewed distributions of mutational effects. More direct evidence comes from spontaneous mutation accumulation (MA) experiments in Drosophila, Caenorhabditis elegans, wheat, yeast, Escherichia coli, and different mutation accumulation (MA) experiments in Arabidopsis. All of these experiments detected downward trends in mutation accumulation (MA) line population mean fitness relative to control populations as generations accrued. As far as we know, there is no case of even a single MA line maintained by bottlenecking that showed significantly higher fitness than its contemporary control populations. 2
M.C. Whitlock (2004): The overall effect of mutation on a population is strongly dependent on the population size. A large population has many new mutations in each generation, and therefore the probability is high that it will obtain new favorable mutations. This large population also has effective selection against the bad mutations that occur; deleterious mutations in a large population are kept at a low frequency within a balance between the forces of selection and those of mutation. A population with relatively fewer individuals, however, will have lower fitness on average, not only because fewer beneficial mutations arise, but also because deleterious mutations are more likely to reach high frequencies through random genetic drift. This shift in the balance between fixation of beneficial and deleterious mutations can result in a decline in the fitness of individuals in a small population and, ultimately, may lead to the extinction of that population. As such, a change in population size may determine the ultimate fate of a species affected by anthropogenic change.3
J.C.Sandord (2022): Genetic Entropy is the genetic degeneration of living things. Genetic entropy is the systematic breakdown of the internal biological information systems that make life alive. Genetic entropy results from genetic mutations, which are typographical errors in the programming of life (life’s instruction manuals). Mutations systematically erode the information that encodes life’s many essential functions. Biological information consists of a large set of specifications, and random mutations systematically scramble these specifications – gradually but relentlessly destroying the programming instructions essential to life. Genetic entropy is most easily understood on a personal level. In our bodies there are roughly 3 new mutations (word-processing errors), every cell division. Our cells become more mutant, and more divergent from each other every day. By the time we are old, each of our cells has accumulated tens of thousands of mutations. Mutation accumulation is the primary reason we grow old and die. This level of genetic entropy is easy to understand. There is another level of genetic entropy that affects us as a population. Because mutations arise in all of our cells, including our reproductive cells, we pass many of our new mutations to our children. So mutations continuously accumulate in the population – with each generation being more mutant than the last. So not only do we undergo genetic degeneration personally, we also are undergoing genetic degeneration as a population. This is essentially evolution going the wrong way. Natural selection can slow down, but cannot stop, genetic entropy on the population level.
Apart from intelligence, information and information systems always degenerate. This is obviously true in the human realm, but is equally true in the biological realm (contrary to what evolutionists claim). The more technical definition of entropy, as used by engineers and physicists, is simply a measure of disorder. Technically, apart from any external intervention, all functional systems degenerate, consistently moving from order to disorder (because entropy always increases in any closed system). For the biologist it is more useful to employ the more general use of the word entropy, which conveys that since physical entropy is ever-increasing (disorder is always increasing), therefore there is universal tendency for all biological information systems to degenerate over time – apart from intelligent intervention.1
1. J.C.Sanford: Genetic entropy 2022
2. Michael Lynch: TOWARD A REALISTIC MODEL OF MUTATIONS AFFECTING FITNESS 2003 Mar
3. Michael C. Whitlock: Fixation of New Mutations in Small Populations 2004