Question:
Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
Updated On: Oct 4, 2023
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Solution and Explanation
Darwinian selection theory states that individuals with favourable variations are better adapted than individuals with less favourable variation. It means that nature selects the individuals with useful variation as these individuals are better evolved to survive in the existing environment. An example of such selection is antibiotic resistance in bacteria. When bacterial population was grown on an agar plate containing antibiotic penicillin the colonies that were sensitive to penicillin died whereas one or few bacterial colonies that were resistant to penicillin survived. This is because these bacteria had undergone chance mutation which resulted in the evolution of a gene that made them resistant to penicillin drug. Hence the resistant bacteria multiplied quickly as compared to non- resistant (sensitive) bacteria thereby increasing their number. Hence the advantage of an individual over other helps in the struggle for existence.
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Concepts Used:
Evolution
Evolution is a process that occurs in changes in the genetic content of a population over time. Evolutionary change is generally classified into two: microevolution and macroevolution. The process of changes in allele frequencies in a population over time is a microevolutionary process. Three main mechanisms that cause allele frequency change are natural selection, genetic drift, and gene flow. On the other hand, macroevolution refers to change at or above the level of the species.