One of the most monumental of all concepts. So many fascinating angles.

Natural Selection is closely related to Hormesis and Antifragility.

Wiki

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations

Wiki: Mechanism: Heritable variation, differential reproduction

Natural variation occurs among the individuals of any population of organisms. Some differences may improve an individual’s chances of surviving and reproducing such that its lifetime reproductive rate is increased, which means that it leaves more offspring. If the traits that give these individuals a reproductive advantage are also heritable, that is, passed from parent to offspring, then there will be differential reproduction, that is, a slightly higher proportion of fast rabbits or efficient algae in the next generation. Even if the reproductive advantage is very slight, over many generations any advantageous heritable trait becomes dominant in the population.

In this way the natural environment of an organism “selects for” traits that confer a reproductive advantage, causing evolutionary change, as Darwin described.[57] This gives the appearance of purpose, but in natural selection there is no intentional choice.

Wiki: Mechanism: Fitness

The concept of fitness is central to natural selection. In broad terms, individuals that are more “fit” have better potential for survival, as in the well-known phrase “survival of the fittest”, but the precise meaning of the term is much more subtle. Modern evolutionary theory defines fitness not by how long an organism lives, but by how successful it is at reproducing. If an organism lives half as long as others of its species, but has twice as many offspring surviving to adulthood, its genes become more common in the adult population of the next generation. Though natural selection acts on individuals, the effects of chance mean that fitness can only really be defined “on average” for the individuals within a population. The fitness of a particular genotype corresponds to the average effect on all individuals with that genotype.[61] A distinction must be made between the concept of “survival of the fittest” and “improvement in fitness”. *“Survival of the fittest” does not give an “improvement in fitness”, it only represents the removal of the less fit variants from a population. *

Wiki: Mechanism: Competition

In biology, competition is an interaction between organisms in which the fitness of one is lowered by the presence of another. This may be because both rely on a limited supply of a resource such as food, water, or territory.[66] Competition may be within or between species, and may be direct or indirect.[67] Species less suited to compete should in theory either adapt or die out, since competition plays a powerful role in natural selection, but according to the “room to roam” theory it may be less important than expansion among larger clades.

Wiki: Arms Race

Natural selection is seen in action in the development of antibiotic resistance in microorganisms. Since the discovery of penicillin in 1928, antibiotics have been used to fight bacterial diseases. The widespread misuse of antibiotics has selected for microbial resistance to antibiotics in clinical use, to the point that the methicillin-resistant Staphylococcus aureus (MRSA) has been described as a “superbug” because of the threat it poses to health and its relative invulnerability to existing drugs.[87] Response strategies typically include the use of different, stronger antibiotics; however, new strains of MRSA have recently emerged that are resistant even to these drugs.[88] *This is an evolutionary arms race, in which bacteria develop strains less susceptible to antibiotics, while medical researchers attempt to develop new antibiotics that can kill them. *

Wiki: Impact: Universal Darwinism

Darwin’s ideas, along with those of Adam Smith and Karl Marx, had a profound influence on 19th century thought, including his radical claim that “elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner” evolved from the simplest forms of life by a few simple principles.[113] This inspired some of Darwin’s most ardent supporters—and provoked the strongest opposition. Natural selection had the power, according to Stephen Jay Gould, to “dethrone some of the deepest and most traditional comforts of Western thought”, such as the belief that humans have a special place in the world.[114]

In the words of the philosopher Daniel Dennett, Darwin’s dangerous idea” of evolution by natural selection is a “universal acid,” which cannot be kept restricted to any vessel or container, as it soon leaks out, working its way into ever-wider surroundings.[115] Thus, in the last decades, the concept of natural selection has spread from evolutionary biology to other disciplines, including evolutionary computation, quantum Darwinism, evolutionary economics, evolutionary epistemology, evolutionary psychology, and cosmological natural selection. This unlimited applicability has been called universal Darwinism.