Chapter 14, Problem 1BYB

Summary Introduction

To determine:

The role of natural selection in the evolution of antibiotic resistance.

Introduction:

Natural selection theory is given by Darwin. It involves the selection of organisms on the basis of their phenotypic characters. Organisms who can survive in any changing habitat and produce offspring in a changing habitat are considered as part of the survival of the fittest theory. Natural selection brings evolution as it causes variations among the individuals and that variation is inherited from their parents. It also leads to cause overproduction of the offspring, such as some organisms produce more offspring than the others due to the presence of variations.

Explanation of Solution

Natural selection promotes evolution due to the presence of variations among individuals. Variations are the results of sexual reproduction in which the male and female gametes are fused to form a zygote. The offspring that are formed then have characteristics of both the parents. Rapid use of antibiotics brings the evolution of antibiotic resistance.

When the bacteria are exposed to the antibiotic, some of the bacteria develop the gene for the antibiotic resistance. This gene allows the bacteria to survive in the presence of antibiotic, as it can break down the antibiotic. So, the bacteria which are capable of breaking down the antibiotic, would survive and the bacteria with no resistance would be eliminated ultimately. So, by this process, all the bacteria having antibiotic resistance would be able to survive.

Conclusion

A mutation that occurs in bacteria is the main reason for antibiotic resistance. It brings evolution because natural selection promotes survival of the fittest as on exposure to antibiotics, some bacteria die, while some become resistant to it and produces its offspring.