LEARN NC was a program of the University of North Carolina at Chapel Hill School of Education from 1997 – 2013. It provided lesson plans, professional development, and innovative web resources to support teachers, build community, and improve K-12 education in North Carolina. Learn NC is no longer supported by the School of Education – this is a historical archive of their website.

a batch of yellow and purple potatoes

In this lesson, students will work as epidemiologists to outline the circumstances of the potato
disease caused by P. infestans and use credible internet resources to research the historical significance of the Great Famine of Ireland.

In this lesson, students use internet resources to determine the factors behind the potato blight that led to the most destructive famine in human history. Students will use the scientific method and inquiry to determine how the pathogen spread over the world and learn some of the historical context surrounding this tragedy.

CSI Dublin: The Hunt for the Irish Potato Killer is an integrated unit incorporating earth science, biology, biotechnology, and art to allow students to apply their understandings of epidemiology and plant pathology into the historical context of science and human health. This unit plan is best used after previous units or discussions on DNA, biotechnology, taxonomy, bacteria, viruses, plants, protists, fungi, and immunity, but is not necessary for this individual lesson plan.

Learning outcomes

The learner will:

  • Employ the scientific method to inquire why the famine was worse in Ireland than in any other location
  • Evaluate internet resources to understand the historical context of late blight
  • Relate plant pathology and poverty to serious risks to human health

Teacher planning

Time required

This lesson requires 50 to 90 minutes of class time. The activity may be finished at home.

  • Pre-activity discussion: 5 minutes depending on student questions
  • Student activity: 45 to 90 minutes depending on student ability (reading) levels
  • Post-activity discussion: 5 minutes depending on student questions

Student handouts

Profiling a potato killer lab sheet
Open as PDF (249 KB, 5 pages)

Technology resources

Students will need access to computers with internet connections.


Prior knowledge and vocabulary

Students should understand the steps of the scientific method as well as terms such as pathogen, epidemic, pandemic, and host. They do not need to know any information about Phytophthora infestans or the Great Famine, as they will learn about these topics within this lesson.


  1. To open the activity, the teacher should review the concepts from the prior days or perhaps review student maps. The time the teacher wishes to dedicate to this activity will vary depending on the nature of the class.
  2. The teacher will explain that P. infestans was the pathogen that caused the Irish potatoes to rot, however there were other factors that caused the Great Famine. Using the lab sheet, have student complete the observation section of the activity. They will be looking at a population graph of Ireland and Europe and considering factors that contribute to population decline. The will also study a map showing the geography of of Ireland and Europe to hypothesize how the potato blight was carried from Belgium to Ireland. The teacher should help students brainstorm possible answers to the questions as they perform this part of the activity.
  3. Students should create a hypothesis based upon the information from their observations as well as the pre-lab discussion. Make sure all students have recorded their own unique hypotheses before they begin their web research.
  4. Have students use the following three websites, also provided on their laboratory sheet, and begin their data collection.
  5. Allow students 40–90 minutes to work independently answering the questions on their lab sheets while monitoring their progress. You may wish to give them an additional day in class to complete this activity on a normal schedule or the entire period on a block schedule.
  6. If students finish their data collection, have them begin the analysis and conclusion questions. They will be answering the following questions:
    • Do you think that P. infestans has a Central American or a South American origin? Explain your answer.
    • Based upon your research, why do you think the pathogen thrived in Europe, Ireland, and the United States instead of its point of origin?
    • Different sources estimate different figures of how many people perished due to the Great Famine. Why do you think there is such a discrepancy?
    • Along with starvation, many Irish people died of epidemic disease. How do you think starvation is linked to outbreaks such as typhus, dysentery, and fever?
    • P. infestans caused the blight of the potatoes, however the Irish Potato Famine is often described as a famine due to poverty. Explain this statement.
    • Re-read your hypothesis. Was it supported or rejected? Why or why not?
  7. In the last remaining minutes of class, review what students have done and find out if there are any questions. Students who did not finish in class should complete their data and/or analysis and conclusion questions for homework (or the next day in class.) Assure students that only their data questions will be assessed upon accuracy whereas the rest of their score depends on the thought and quality of their responses. Ensure that all students can complete the assignment.
  8. Following is an optional homework assignment. It can be also used by a history or English teacher to help students write in a historical or different person’s perspective.
  9. Profiling a potato killer optional narrative assignment
    Open as PDF (152 KB, 2 pages)


  • The teacher will score the student responses based upon completion of each step of the scientific method. The twenty-nine data questions should be assessed upon accuracy and quality of student responses as well as the one extra credit question. The six conclusion questions should be graded based upon use of critical thinking skills.
  • The optional homework should be assessed by the rubric included in the handout.


  • Some schools may or may not have access to computers with internet access. In this case, save and print the articles. These print-outs can also be distributed to students who do not finish in class and do not have technology access at home.
  • ESL and ELL students may use an online translator such as Google Translator to translate entire web pages into their preferred language. They can print these pages to take home, if needed.



  • Because P. infestans is the causative agent of the potato disease and subsequent famine, be vigilant and ensure that students do not acquire the misconception that every time there is a P. infestans outbreak, there will be a famine.
  • It is important for students to understand the importance of observations in formulating a hypothesis. Teachers should foster the creative and unique thought processes and emphasize that there is no right or wrong answer, only supported or not supported.
  • Some students may not have access to internet resources or a computer at home. Encourage students to stop by at the end of the school day (or other convenient time for student and teacher) to get printed copies of the material to read at home.
  • It would be a good idea to meet with your students’ teachers in the disciplines mentioned in the extensions to determine what activities can be done together to help reinforce student engagement and learning.

  • North Carolina Essential Standards
    • Science (2010)
      • Biology

        • Bio.2.1 Analyze the interdependence of living organisms within their environments. Bio.2.1.1 Analyze the flow of energy and cycling of matter (water, carbon, nitrogen and oxygen) through ecosystems relating the significance of each to maintaining the health...
      • Grade 8

        • 8.L.1 Understand the hazards caused by agents of diseases that effect living organisms. 8.L.1.1 Summarize the basic characteristics of viruses, bacteria, fungi and parasites relating to the spread, treatment and prevention of disease. 8.L.1.2 Explain the difference...

North Carolina curriculum alignment

Science (2005)

Grade 9–12 — Biology

  • Goal 1: The learner will develop abilities necessary to do and understand scientific inquiry.
    • Objective 1.01: Identify biological questions and problems that can be answered through scientific investigations.
    • Objective 1.02: Design and conduct scientific investigations to answer biological questions.
      • Create testable hypotheses
      • Identify variables.
      • Use a control or comparison group when appropriate.
      • Select and use appropriate measurement tools.
      • Collect and record data.
      • Organize data into charts and graphs.
      • Analyze and interpret data.
      • Communicate findings.
    • Objective 1.03: Formulate and revise scientific explanations and models of biological phenomena using logic and evidence to:
      • Explain observations.
      • Make inferences and predictions.
      • Explain the relationship between evidence and explanation.
    • Objective 1.05: Analyze reports of scientific investigations from an informed, scientifically literate viewpoint including considerations of:
      • Appropriate sample.
      • Adequacy of experimental controls.
      • Replication of findings.
      • Alternative interpretations of the data.
  • Goal 4: The learner will develop an understanding of the unity and diversity of life.
    • Objective 4.04: Analyze and explain the interactive role of internal and external factors in health and disease:
      • Genetics.
      • Immune response.
      • Nutrition.
      • Parasites.
      • Toxins.
  • Goal 5: The learner will develop an understanding of the ecological relationships among organisms.
    • Objective 5.03: Assess human population and its impact on local ecosystems and global environments:
      • Historic and potential changes in population.
      • Factors associated with those changes.
      • Climate change.
      • Resource use.
      • Sustainable practices/stewardship.