Antibiotics and Natural Selection

Evolutionary Biology, in particular the understanding of how organisms evolve through natural selection, as proposed by Charles Darwin, is an area of science with many practical applications. Creationists (those who purely believe that God created man in His image and did not evolve from primates) often claim that the Theory of Evolution lacks practical applications, but this has already been refuted by scientists.

Antibiotic resistance can be explained through Darwin's theory. When there is a wrong use of antibiotics (when the patient did not consume all the antibiotics that were prescribed), it causes some of the population of bacteria in the body to resist (adapt to their environment) and change over time (by survival of the fittest).

This can be explained by the steps of Darwin's Natural Selection:

1. Overproduction: there are more bacteria in the body to maintain a population.
2. Competition: bacteria in the body compete with food and space in order to produce and grow.
3. Variation: different bacteria are found in the body. Some of the bacteria react differently to antibiotics than other bacteria.
4. Adaptation: some variations in the bacteria allow them to resist antibiotics that kill many other types of bacteria. These beneficial variations are considered adaptations because they allow the bacteria to not be affected by the antibiotics, and continue to live instead of getting killed with the other bacteria.
5. Differential Reproductive Success: over time, the bacteria with adaptation (resistance to antibiotics) were more likely to survive and reproduce.
6. Changes in Gene Pool Over Time: through differential reproductive success, over time, the resistant bacteria were more likely to survive and pass on their trait (resistance to antibiotics) to their offspring. 

There is also a step called Speciation. It occurs when some of the population get variations and adaptations generations after generations and become so different from the rest of the population that the two types can no longer mate and produce an offspring. They are then considered different species. The one that did not get this variation died (survival of the fittest). Therefore, the bacteria that will be left after natural selection will all be antibiotic resistant.

x-----x

Picture from Pixabay.