Food for a Hungry Planet

Predicting the future is an inexact art. However, we know that in order to feed the ever-growing human population we must have sufficient arable land, mineral nutrients, and fresh water. Some agricultural scientists think that we are in the midst of a “perfect storm” in which a large human population, limited resources, and environmental climate change are going to challenge our ability to produce enough food. In addition, diseases continually arise to threaten our food crops (such as cassava) and our cash crops (such as cacao). Scientists work to find solutions to these problems, but contributions from educated people in many fields will be necessary to help us feed our hungry planet.

• Chapter 14 Podcast

  Chapter 14 Podcast​
  

  Listen to the Podcast (mp3)
  

  The short podcast provided for each chapter includes a review of a major concept or issue, clarification of an important point that can be confusing to students, and questions for students to think about. This podcast discusses perceptions of risk and the concept of relative risk and contrasts the terms natural and synthetic.

• Demonstration

  Air Quality Observations

  Go to the website AIRNow to view maps of air quality conditions and forecasts. Watch the animations for the entire United States, or choose a local map relevant to the students.

  To prepare for this activity, review temperature data from one or more past summers to find a particularly hot day. Have students observe the change in the air quality index (AQI) over 24 hours and compare the maps of peak ozone and peak particles. Students should note the diurnal variations due to the presence of sunlight and increasing air temperature, which cause the photochemical reaction that produces ozone over the course of a day.

  Also compare peak ozone maps for July and January. Ask students why ozone is less of a problem in the winter.

  
  

  1) Pathogen Group Comparison

  Break the class into small groups of 3–5 students, and have each group fill in the following grid.

  Note: If students have been completing review grids throughout the semester, they should be able to fill in the categories in the top row and left column of this grid. If students are not used to the review grids, you can provide them the grid with these categories filled in and the rest blank. (See the completed Sample Grid for possible answers.)

  
  
• Short Writing Assignments

  Notes: These assignments require each student to write a paragraph (introductory sentence, body, concluding sentence) and can be completed in 10–15 minutes in class. They provide a good way to check student comprehension and to improve student writing skills. See Chapter 1 for a simple grading system.

  
  

  1) Global Climate Change and Abiotic Disease

  The topic of human-induced global climate change is frequently in the news. Changes in the global climate will lead to changes in the abiotic environment, and those changes may lead to increases in certain abiotic plant diseases. Describe two abiotic plant diseases that could occur more frequently as a result of predicted climate changes. Include in your description a discussion of how the change in climate will lead to an increase in these two abiotic diseases. What steps might plant scientists consider now to help prevent future disruptions in the global food supply that could result from global climate change?

  
  

  2) Abiotic Versus Biotic Diseases

  Describe two differences between biotic and abiotic diseases of plants, and give an example of each type of disease. Knowing that many diseases can adversely affect plants and that symptoms of different diseases can be similar, why is it important to be able to accurately diagnose the causes of plant diseases?