Description
This lab serves as a demonstration of natural selection and of evolution occurring over a short span of time. Students examine the evolution of bacterial populations grown both in the absence of, and presence of, an antibiotic.
Time Requirement
Total, 270 minutes over 2 weeks. Setting up the experiment, 1 lab period. Collecting data over the next 5 days, 15 to 20 minutes a lab period. Discussion and assessment, 2 to 3 lab periods.
Digital Resources
Includes 1-year access to digital resources that support 3-dimensional instruction for NGSS. Digital resources may include a teacher manual and student guide, pre-lab activities and setup videos, phenomenon videos, simulations, and post-lab analysis and assessments.
Performance Expectation(s)
HS-LS4-2 and HS-LS4-3
Crosscutting Concepts
Cause and Effect
Disciplinary Core Ideas
LS4.B: Natural Selection
LS4.C: Adaptation
Science and Engineering Practices
Engaging in Argument from Evidence
Learning Objectives
- Measure the differences in 2 populations that develop in response to different selective pressures.
- Explain the process of natural selection and how it affects population genetics.
- Describe bacterial antibiotic resistance and how and why it is maintained.
- Use sterile technique, perform a serial dilution, and plate bacteria.
Prerequisite Knowledge and Skills
Students need to be familiar with bacteria and have a basic knowledge of their structure and genetics. They should have a working knowledge of genes, mutation, and proteins (including enzymes). They also need a preliminary knowledge of natural selection and evolution. Students should be able to use a micropipet and have some knowledge of sterile technique.