Energy Laws and Ecology Questions
1. A field of corn contains a certain amount of food energy. If cattle eat the corn, they will gain some of that energy. How does the amount of energy in the corn compare with the amount of energy in the cattle? Is it more efficient to feed on corn or beef? In this activity, you will compare the energy content of some familiar human foods
The table below lists the average amount of energy (in kilojoules per square meter of land per year) in different organisms that people use for food.
|
Organism
|
Energy (KJ/m2/year)
|
Producer (P) or Consumer (C)
|
|
Wheat cereal
|
3 400
|
|
|
Oranges and grapefruits
|
4 200
|
|
|
Pork (pig)
|
800
|
|
|
Peanuts
|
3 850
|
|
|
Rice
|
5 200
|
|
|
Milk (cow)
|
1 800
|
|
|
Potatoes
|
6 700
|
|
|
Chicken
|
800
|
|
|
Carrots
|
3 400
|
|
|
Other vegetables
|
840
|
|
|
Apples
|
6 300
|
|
|
Peaches
|
3 800
|
|
|
Beef (cow)
|
550
|
|
|
Beet sugar
|
8 300
|
|
|
Cane sugar
|
14 650
|
|
|
Fish
|
8
|
|
|
Corn
|
6 700
|
|
|
Eggs (chicken)
|
840
|
|
a. Categorize the organisms in the table as a producer or consumer by placing either a P (for producer) or C (for consumer) in the right hand column on the table.
b. Calculate the AVERAGE energy of all the producers. Show all your calculations.
c. Calculate the AVERAGE energy of all the consumers. Show all your calculations.
d. Which organisms (producers or consumers) can offer more energy on average to the trophic level that feeds on them?
e. Do you think it is more efficient for people to eat plant products or animal products? Why?
2. What is the 10% biomass rule?
3. Someone studied a freshwater spring community and found about 800 grams of plants per square meter of ecosystem. About how much herbivore biomass would you expect her to find? Why?
4. The amount of energy available to a family of mountain lions is limited by the intensity and duration of sunlight in their region. True or false? Why?
5. What type of flow does energy show through an ecosystem? What about matter?
6. It has been said that nature wastes nothing. How would you respond to the skeptic who said, "When I walk through a woods I see all kinds of waste. Dead leaves, tree branches, and stuff. Those things are all made of atoms and molecules. It sure looks like waste to me."
7. Carbon cycle sounds so academic, so remote from our everyday lives. In fact, just the opposite is true. We all participate in this and the other cycles constantly.
a. List at least 3 ways in which our bodies participate in the carbon cycle directly. (One of these is a bit morbid.)
b. Can you think of other ways we participate in the carbon cycle through our activities? (Use things that we do/use - do not use bodily functions or actions)