Evolution of antibiotic resistance in bacteria

Elena Bray Speth (Saint Louis University), Tammy Long (Michigan State University), and Jenni Momsen
(Michigan State University)
Author Profile


This activity is intended to guide students to apply principles of evolution by natural selection to explain a real world biological phenomenon (the evolution of bacteria populations resistant to common antibiotics).

This activity involves making observations, linking evidence to theory, and constructing scientific arguments and conceptual models that incorporate multiple scales of biological organization (molecular, organismal, population) in the context of a changing environment, over time.

Used this activity? Share your experiences and modifications



The activity is used in an introductory biology course for science majors (Organisms and Populations).

Skills and concepts that students must have mastered

Before working on this activity, students had practiced:
a) constructing scientific arguments, as claims based on evidence and supported by appropriate reasoning and scientific theories;
b) creating conceptual models to represent structures, behaviors and functions of complex systems.

Students had already worked on the biological concepts of phenotypic variation, genetic variation, fitness and population change over time.

How the activity is situated in the course

The activity followed teaching and learning about the fundamental principles of evolution by natural selection, and gave students the opportunity to connect multiple important concepts within a single case.


Content/concepts goals for this activity

Learning Objectives:
1. Apply the general definition of Natural Selection to explain the evolution of antibiotic resistance in bacteria populations.
2. Use data (evidence) to make claims about variation, fitness, selection and evolution in populations.

Higher order thinking skills goals for this activity

1. Formulation of scientific arguments;
2. Application of general concepts to a specific case;
3. Interpretation of graphs and other kinds of evidence;
4. Synthesis of multiple concepts in a single concept model.

Other skills goals for this activity

The activity was used in the context of a large-enrollment course in which students worked in permanent cooperative groups, to discuss ideas, solve problems, etc.

Description of the activity/assignment

Most students are familiar with the use of antibiotics and antibacterial products; most have heard in various contexts about the problem of bacterial populations becoming resistant to antibiotics over time.
We used this example, relevant to everyday life, to guide students to uncover the complexity of the underlying biological mechanism, and to "see" how the evolution principles they have learned are interconnected and apply to a specific case.

Determining whether students have met the goals

We collected and graded the models students developed at the end of class. In addition, on the following in-class quiz, students had to complete a "concept frame" that aligned two independent examples of evolution by natural selection (one of which was the case of antibiotic resistance in bacteria) and asked students to explain how each of five fundamental principles applied in each case.

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials