Janis Lariviere, Barbara Mannion, O. Truman Holtzclaw, Randyl Warehime and Arthur Broga
1991 Woodrow Wilson Biology Institute
MIDDLE-LEVEL BIOLOGY: Determine the percent of total calories for the year that come from plant products and the percent from animal products (including dairy products and eggs). Divide the calories from animal products by 200 kcal/square meter/year [200 kcal/square meter/year is a compromise value for all animal products.] Divide the calories from plant products by 2000 kcal/square meter/year (another compromise value). The plant and animal products combined represent the total square meters of land required to support the individual.
ADVANCED BIOLOGY: Use the attached Analysis Sheet for Trophic Ecology of Humans and the students' calorie data to determine the square meters of land required to support the individual. Do this by determining the number of calories that fall into each food category and divide each of these values by the "yield". Add all the values in the "square meters of land" column to arrive at the total land required to support the individual. Add the values in each subgroup, C-3 plants, C-4 plants, and animal products, to compare plant and animal land requirements.
b. On maps of your community and/or state, shade in the land area needed to support your school, community, and state. [To make this easier mark grids on the maps showing square kilometers. Students need to convert the square METERS of land needed to square KILOMETERS of land by dividing the value by 1 million. 1 mile = 1.6 kilometers.]
a. Choose one plant product (e.g., rice) and one animal product (e.g., beef) from the Analysis Sheet for Trophic Ecology of Humans. Assume that an individual takes in 200 calories of each product in one meal. Divide the 200 calories by the yield from the Analysis Sheet. [e.g., Rice: 200 kcal Ö 1250 kcal/sq m = 0.16 sq m; Beef: 200 kcal Ö 130 kcal/sq m = 1.5 sq m]. Give each student a meter stick and have them measure these areas in the field or classroom in order to visualize the difference. Any foods from the Analysis Sheet could be used. A discussion on vegetarian versus non-vegetarian diets would be appropriate.
b. Assuming a student takes in 2000 kcal per day, he/she would take in 730,000 kcal per year. Choose one plant product (e.g., rice) and one animal product (e.g., beef) from the Analysis Sheet for Trophic Ecology of Humans. Divide the 730,000 kcal by the yield from the Analysis Sheet [e.g., Rice: 730,000 kcal Ö 1250 kcal/sq m = 584 sq m; Beef: 730,000 kcal Ö 130 kcal/sq m = 5615 sq m]. Calculate how many football fields/ soccer fields each of these values would represent. [e.g., Rice: 584 sq m Ö 5000 sq m/field = .11 football/soccer fields; Beef: 5615 sq m Ö 5000 sq m/field = 1.1 football fields/soccer fields]. A discussion on vegetarian versus non-vegetarian diets would be appropriate.
Editors of Consumer Guide, Calorie, Carbohydrate and Fat Counter, Publications International, Skokie, Illinois, 1982.
Fat and Cholesterol Counter, American Heart Association, Random House, 1991.
Food Values: Calories, Harper and Row, New York,1990.
Netzer, Corinne, The Complete Book of Food Counts, Dell Publishing, New York, 1988.
Williams, Walden, Vest Pocket Calorie Counter, Doubleday, New York, 1990.
|Food Category||Your Daily Consumption |
|Your Annual Consumption |
|Square Meters of Land|
Required to Support You
(Consumption Ö Yield)
|Wheat, cereal|| ||810|
|Oranges, grapefruit|| ||1000|
|Frozen orange juice|| ||410|
|Peanut butter|| ||920|
|Rice, rice cereal|| ||1250|
|Other vegetables|| ||200|
|Pears, peaches|| ||900|
|Vegetable oil|| ||300|
|Beet sugar|| ||1990|
|Cane sugar|| ||3500|
|Soft drinks|| ||3500|
|Corn cereal|| ||1600|
|Fish (frozen)|| ||2|
Source: Brewer, Richard and M. T. McCann, Laboratory and Field Manual of Ecology, Saunders College Publishing, Philadelphia, 1982.