Calculating Land Area

Name Class Date

Exploration Lab CONSUMER

Calculating Land Area

All living organisms require food for energy and nutrition. Plants produce their own food energy from sunlight through the process of photosynthesis. This transformation of energy provides the basic food source for all other organ isms in the food web, including you.

A typical teenager’s diet contains 2,500-3,000 Calories per day, or about 1 million Calories annually. Calories are units for measuring energy. The definition of a calorie is the amount of energy needed to raise the temperature of 1 gram of water1ºC. This is a small unit of measurement compared with what a person eats normally. Food energy is usually measured in kilocalories (kcal). One kcal equals 1,000 calories or one nutrition Calorie (spelled with an uppercase C). All energy values for food are reported in either Calories or kcals.

You can find nutritional information on the box or wrapper of most packaged foods. Fast-food restaurants provide nutritional information for their menu items on request. For other items, you will need to look up the Calorie information in a calorie counter, a reference book that lists most foods and their caloric content.

The estimated energy captured by crop food plants is about 2,000 Calories per square meter of cropland per year (a number based on the average energy values of several different crops). Likewise, an estimate of livestock or animal energy production is about 200 Calories per square meter of cropland. This figure is much lower because animals absorb only a fraction of the energy contained in the plants they eat. The values for energy production for plants and animals can be used to calculate the amount of cropland required to maintain a particular diet.

How much of Earth’s resources does it take to provide the food energy to support you, your family, or the people in your community? These are important questions as the human population continues to increase. In this activity, you will investigate the land resources necessary to support the food that you eat.

OBJECTIVES

Collect data on your eating habits.

Discover how much farmland is required to support your diet.

Compare how much land is required to support an entire city on your diet to the land required to support a city on a vegetarian diet.

MATERIALS

• calculator

• Calorie charts

Procedure

1. Prior to class, keep track of types and quantities of food you eat in a 24-hourperiod, including between-meal snacks and desserts. Write this information in Table 1 on the next page. List plant items (vegetables, fruits, and grains) and animal items (meats, dairy, eggs, fish) separately.

Calculating Land Area continued

2. During class, using the Calorie charts, record the number of Calories for the food you consumed in Table 1. For some food items, such as pizza or cheeseburgers, you’ll need to estimate the proportion of total Calories of plant sources and animal sources and assign them accordingly.

TABLE 1: CALORIE COUNTING DATA

Item / Quality / Plant
Calories / Animal
Calories
Breakfast / ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______
Lunch / ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______
Dinner / ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______
Snack or other / ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______/ ______
______
______
______
______
Daily totals / ______/ ______
Annual totals / ______/ ______
Annual Calories consumption / ______

Calculating Land Area continued

3. Total the number of Calories you consumed from plant and animal products and record the totals in Table 1.

4. Multiply the daily total of plant Calories by 365 and record the result in Table 1. This is an estimate of your yearly Calorie consumption of plant foods.

5. Multiply the daily total of animal Calories by 365 and record the result in Table1. This is an estimate of your yearly Calorie consumption of animal foods.

6. Add the results of steps 4 and 5 and record the result in Table 1. This is an estimate of your total yearly Calorie consumption.

Analysis

1. Describing Events Describe how your eating habits may have been affected during the performance of this lab.

2. Organizing Data Calculate the amount of cropland required to support you for a year by dividing your annual plant Calories by 2,000 Calories per square mete r, dividing your annual animal Calories by 200 Calories per square meter, and add the results of the two division operations. Show all calculations. How many total square meters of farmland do you require?

3. Examining Data Compare your diet to that of the average teenager. The land area necessary to produce the yearly food energy in a typical teenager’s diet is about 2,000 square meters. How do you compare?

4. Classifying Break down the number of your Calories into percentages of plant food and animal food. Show calculations.

Calculating Land Area continued

5. Analyzing Data Compare the percentage of plant food Calories in your dietto animal food Calories in your diet. Do you tend to eat more plant or animal food? How do you think this compares to the average teenager?

6. Identifying Patterns Identify patterns that you see in your eating habits and how they may have affected your results.

Conclusions

7. Drawing Conclusions Model a city that has a population of 10 million people(e.g., New York) with a diet similar to yours. How many square meters of land would it take to grow the food for your model city? There are 2.56 million square meters in 1 square mile of land. How many square miles of crop land would it take to feed all of the people of your model city? Show all calculations.

8. Applying Conclusions Model another city with the same population on a vegetarian diet. Assume that each person consumes an average of 1 million Calories per year. Assuming the 2,000 Calories per square meter captured by plants, calculate the number of square meters and the number of square miles needed to support this model city. Show all calculations.

Holt Environmental science 39 How Ecosystems Wonk

TEACHER RESOURCE PAGE

Exploration Lab CONSUMER

Calculating Land Area

Teacher Notes

TIME REQUIRED One day prior to class and one 45-minute class period

SKILLS ACQUIRED

Classifying

Collecting data

Communicating

Identifying and recognizing patterns

Organizing and analyzing data

RATING

Teacher Prep–1

Student Set-Up–3

Concept Level–3

Clean Up–1

THE SCIENTIFIC METHOD

Make Observations Procedure, steps 1–6

Analyze the Results Analysis, questions 2–6

Draw Conclusions Conclusions, questions 7 and 8

MATERIALS

Calorie-counting booklets are available at grocery store book counters and in reference libraries. The Internet is also an excellent source.

Name Class Date

Exploration Lab CONSUMER

Calculating Land Area

A typical teenager’s diet contains 2,500-3,000 Calories per day, or about 1 million Calories annually. Calories are units for measuring energy. The definition of a calorie is the amount of energy needed to raise the temperature of 1 gram of water1ºC. This is a small unit of measurement compared with what a person eats normally. Food energy is usually measured in kilocalories (kcal). One kcal equals1,000 calories or one nutrition Calorie (spelled with an uppercase C). All energy values for food are reported in either Calories or kcals.

You can find nutritional information on the box or wrapper of most packaged foods. Fast-food restaurants provide nutritional information for their menu item son request. For other items, you will need to look up the Calorie information in a calorie counter, a reference book that lists most foods and their caloric content.

OBJECTIVES

Collect data on your eating habits.

Discover how much farmland is required to support your diet.

Compare how much land is required to support an entire city on your diet to the land required to support a city on a vegetarian diet.

MATERIALS

• calculator

• Calorie charts

Procedure

Name Class Date

Calculating Land Area continued

2. During class, using the Calorie charts, record the number of Calories for the food you consumed in Table 1. For some food items, such as pizza or cheese burgers, you’ll need to estimate the proportion of total Calories of plant sources and animal sources and assign them accordingly

TABLE 1: CALORIE COUNTING DATA

Name Class Date

Calculating Land Area continued

3. Total the number of Calories you consumed from plant and animal products and record the totals in Table 1.

4. Multiply the daily total of plant Calories by 365 and record the result in Table 1. This is an estimate of your yearly Calorie consumption of plant foods.

5. Multiply the daily total of animal Calories by 365 and record the result in Table1. This is an estimate of your yearly Calorie consumption of animal foods.

6. Add the results of steps 4 and 5 and record the result in Table 1. This is an estimate of your total yearly Calorie consumption.

Analysis

1. Describing Events Describe how your eating habits may have been affected during the performance of this lab.

Answers may vary. Sample answer: I became very self-conscious of my eating.__

I found that I was thinking about it all the time. I think I did not eat as much___

as I usually would have.______

2. Organizing Data Calculate the amount of cropland required to support you for a year by dividing your annual plant Calories by 2,000 Calories per square meter, dividing your annual animal Calories by 200 Calories per square meter, and add the results of the two division operations. Show all calculations. How many total square meters of farmland do you require?

Answers may vary. Sample Answer: 3,000,000 plant Calories / 2,000 plant_____

Calories/sq. m. = 1,500 sq. m.; 1,000,000 animal Calories / 200 animal______

Calories/sq. m. = 5,000 sq. m. I require 6,500 sq. m. of farmland to support_____

my diet.______

Answers may vary. Sample answer: I require 4,500 square meters more than___

the average teenager. I eat much more than the average teenager.______

4. Classifying Break down the number of your Calories into percentages of plant food and animal food. Show calculations.

Answers may vary. Sample answer: Plant food: 3,000,000 plant Calories /______

4,000,000 total Calories = 75% Calories from plant food; Animal food: 100%___

total Calories - 75% from plant food = 25% Calories from animal food.______

Name Class Date

Calculating Land Area continued

Answers may vary. Sample answer: I eat more plant food. I think the average__

teenager must have a higher percentage of Calories from plant food since the___

average teenager requires less land.______

6. Identifying Patterns Identify patterns that you see in your eating habits and how they may have affected your results.

Answers may vary. Sample answer: I find that I am eating a lot of fast food,____

even when I am at home. This explains the large percentage of Calories from___

animal foods.______

Conclusions

7. Drawing Conclusions Model a city that has a population of 10 million people(e.g., New York) with a diet similar to yours. How many square meters of land would it take to grow the food for your model city? There are 2.56 million square meters in 1 square mile of land. How many square miles of cropland would it take to feed all of the people of your model city? Show all calculations.