Question

Q Explain biological evolution with reference to antibiotic resistance observed in bacteria in light of darwinian natural selection theory.​

Answer 1

Antibiotics have always been considered one of the wonder discoveries of the 20th century. This is true, but the real wonder is the rise of antibiotic resistance in hospitals, communities, and the environment concomitant with their use. The extraordinary genetic capacities of microbes have benefitted from man's overuse of antibiotics to exploit every source of resistance genes and every means of horizontal gene transmission to develop multiple mechanisms of resistance

Answer 2

Answer:

1. Darwinian selection theory states that individuals with favourable variations are better adapted than individuals with less favourable variation.
2. It means that nature selects the individuals with useful variation as these individuals are better evolved to survive in the existing environment.
3. An example of such selection is antibiotic resistance in bacteria.
4. 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.
5. This is because these bacteria had undergone chance mutation, which resulted in the evolution of a gene that made them resistant to penicillin drug.
6. Hence, the resistant bacteria multiplied quickly as compared to non-resistant (sensitive) bacteria, thereby increasing their number.
7. Hence, the advantage of an individual over other helps in the struggle for existence.