Bacteria

=Bacteria become resistant to antibiotics when a few individual resistant bacteria survive and reproduce, passing their resistance on to the next generation.=

Which of the following correctly describes what happens when a population of bacteria becomes resistant to an antibiotic? Note: a bacterium is one individual in a group of bacteria.

A) During treatment with an antibiotic, each individual bacterium tries to become resistant to the antibiotic. Only some are able to willingly become resistant, and these individuals survive to pass this trait to their offspring.

B) During treatment with an antibiotic, all of the bacteria gradually become more resistant to the antibiotic the more they are exposed to it. They all survive and pass this trait to their offspring.

C) During treatment with an antibiotic, a population of bacteria usually dies. Sometimes by chance, all members of the population become resistant at once, survive, and pass their resistance to their offspring.

D) During treatment with an antibiotic, only those individual bacteria that already have a trait that helps them survive the effects of the antibiotic will live. Their offspring in the next generation will also have this trait.

Correct Answer: D

Misconceptions
ENM031: Individual organisms can deliberately develop new heritable traits because they need them for survival (Bishop & Anderson 1990; Passmore et al., 2002; Stern & Roseman, 2004).
 * Answer Choice: A**

ENM037: Changes in a population occur through a gradual change in all members of a population, not from the survival of a few individuals that preferentially reproduce (Brumby, 1979; Bishop & Anderson, 1990; Anderson et al., 2002; Stern & Roseman, 2004). ENM047: Evolution happens when individual organisms acclimate or "get used to" new conditions gradually (Bishop & Anderson, 1990).
 * Answer Choice: B**

ENM033: Change to the characteristics of populations (i.e. the proportion of individuals in the population having certain traits) of organisms is always random, and is not influenced by the favorability of that change in a given environment (AAAS Project 2061, n.d.).
 * Answer Choice: C**

Bacteria can evolve when antibiotics kill the nonresistant ones and the resistant ones can multiply in the next generation.
 * 1) evolution