Why the amp R gene offers or does not offer an advantage when grown in the environment of these petri dishes.?

The ampR gene provides a selective advantage in environments containing ampicillin, as it encodes for beta-lactamase, an enzyme that breaks down the antibiotic, allowing bacteria carrying this gene to survive and proliferate. In petri dishes with ampicillin, only those bacteria with the ampR gene can thrive, leading to their dominance in that environment. Conversely, in the absence of ampicillin, the ampR gene may not confer any significant advantage, as it does not contribute to other essential survival traits. Thus, the gene's advantage is context-dependent, thriving only in antibiotic-rich environments.