Intro. Medical microbiologists believe that overuse of antibiotics in animal feed may select for antibiotic resistant bacteria which subsequently can be passed on to humans, potentially causing infection by these antibiotic resistant bacteria. This is an example of_ Biological evolution by natural selection O Enzymes which cause really high mutations rates in the bacterial DNA O drugs acting as mutagens Phenotypic drift caused by random mutations
Evolutionary Genetics
Evolution is known as continuous changes that occur to adjust organisms in their changing environment over many generations. Various theories have been proposed to illustrate the origin of life and organic evolution. The most accepted one is the theory of natural selection by Charles Darwin. According to his postulate, organisms undergo a struggle for existence due to overproduction. To survive in nature, they acquire variations. The inheritable variations are selected by nature, and it leads to the survival of the fittest.
Phenotype Frequency
The majority of populations have a certain degree of variation in their genetic pools. Scientists can predict the genetic variation happening over time by measuring the amount of genetic variation in a population and these predictions assist them in gaining important insights into the processes that allow organisms to adapt to the environment or to develop into new species over generations. This process is referred to as the process of evolution.
Hardy Weinberg Equilibrium
The frequencies of allele and genotype were maintained constant from one generation to another due to the absence of other evolutionary forces. It is otherwise called the Hardy Weinberg principle the field of population genetics.
Antibiotic resistance (ABR) occurs when bacteria evolve mechanisms that protect them from the effects of antibiotics. Resistant bacteria are more difficult to treat, requiring higher doses, or alternative medications which may prove more toxic.
First option is correct because in a large population of bacteria, there may be some that are not affected by antibiotic caused by mutations in single bacteria. These survive and reproduce when frequent overuse of antibiotic is done and produces more bacteria that are not affected by the antibiotic. This is known as Natural selection of antibiotic strain of bacteria produced by random mutation. Thus, the statement in the question about antibiotic resistance is an example of biological evolution by natural selection.
Second option is correct because in the given statement, the enzymes are not involved in increasing the mutation rates of bacteria but more and more antibiotic resistant bacteria get produced through natural selection.
Third option is incorrect because antibiotics do not increase or cause mutation but produce a competitive environment for bacteria in which resistant strain is selected naturally and flourishes.
Fourth option is incorrect because random mutation causes change in strain of single bacteria which increases its population when the more and more antibiotics are introduced in the environment of bacteria and thus resistant strain getting naturally selected.
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