Question

this chapter discusses the evolution of staphylococcus aureus populations and antibiotic resistance. review the figure in the text then apply what you know about the general patterns of evolution. drag the appropriate labels to the appropriate parts of the figure to indicate which pattern occurred when s. aureus was exposed first to methicillin and then to vancomycin. stabilizing selection after exposure to vancomycin stabilizing selection after exposure to methicillin disruptive selection after exposure to methicillin directional selection after exposure to methicillin disruptive selection after exposure to vancomycin directional selection after exposure to vancomycin drag each item above to its appropriate location in the image. note that every item may not have a match, while some items may have more than one match.

Explanation:

1. When \( S. aureus \) is exposed to methicillin, the population shifts toward methicillin - resistant strains. This is directional selection (favors one extreme phenotype).
2. After exposure to vancomycin, if the population stabilizes around a phenotype (e.g., a level of resistance that is optimal), it is stabilizing selection. So the correct labels are: "directional selection after exposure to methicillin" and "stabilizing selection after exposure to vancomycin".

Answer:

directional selection after exposure to methicillin, stabilizing selection after exposure to vancomycin