Humans require energy and their energy is obtained from food. Land therefore yields fewer kilocalories per square meter per year in animal products than in plant products.
Energy is lost in the transition from producers to consumers.
Student records the types and amount of food eaten during a 24-hour period. Be sure to count everything, not just what is eaten at meals - snacks, candy, etc. too. Using calorie counter references, determine the total number of calories taken in during those 24 hours. Multiply this amount by 365 to determine the total number of calories taken in during a year. The plant and animal products combined represent the total square meters of land required to support the individual.