7th grade ecosystems and food chains

Question 1

Why is only about 10% of energy passed to the next level of a food chain?

• A. Energy is destroyed at each level
• B. Much is used for respiration and movement, or lost as heat and waste
• C. Animals refuse to eat most of their food
• D. Plants keep all the energy

Question 2

A level of a food chain contains 5000 kJ. The next level gets 750 kJ. What is the percentage efficiency of the energy transfer?

Answer %

Question 3

Producers in a field capture 20000 kJ of energy. About 10% of the energy passes to each next level. How much energy reaches the tertiary consumers, in kJ?

Answer kJ

Question 4

Why is it more energy-efficient for people to eat plants than to eat animals fed on plants?

• A. Meat is always unhealthy
• B. Plants have more protein than meat
• C. Animals contain no energy
• D. Energy is lost at each extra level of the food chain

Question 5

A level of a food chain contains 8000 kJ. The next level gets 1200 kJ. What is the percentage efficiency of the energy transfer?

Answer %

Question 6

Producers in a field capture 20000 kJ of energy. About 10% of the energy passes to each next level. How much energy reaches the primary consumers, in kJ?

Answer kJ

Question 7

Why is it more energy-efficient for people to eat plants than to eat animals fed on plants?

• A. Meat is always unhealthy
• B. Energy is lost at each extra level of the food chain
• C. Animals contain no energy
• D. Plants have more protein than meat

Question 8

A level of a food chain contains 5000 kJ. The next level gets 1000 kJ. What is the percentage efficiency of the energy transfer?

Answer %

Question 9

Producers in a field capture 20000 kJ of energy. About 10% of the energy passes to each next level. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 10

Why do food chains rarely have more than four or five levels?

• A. Plants stop growing
• B. Top predators do not need energy
• C. There is too little energy left to support more levels
• D. There are not enough names for them

Question 11

A level of a food chain contains 10000 kJ. The next level gets 1500 kJ. What is the percentage efficiency of the energy transfer?

Answer %

Question 12

Producers in a field capture 10000 kJ of energy. About 10% of the energy passes to each next level. How much energy reaches the tertiary consumers, in kJ?

Answer kJ

Question 13

Why do food chains rarely have more than four or five levels?

• A. There is too little energy left to support more levels
• B. Top predators do not need energy
• C. Plants stop growing
• D. There are not enough names for them

Question 14

A level of a food chain contains 8000 kJ. The next level gets 640 kJ. What is the percentage efficiency of the energy transfer?

Answer %

Question 15

Producers in a field capture 20000 kJ of energy. About 10% of the energy passes to each next level. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 16

Why is it more energy-efficient for people to eat plants than to eat animals fed on plants?

• A. Energy is lost at each extra level of the food chain
• B. Plants have more protein than meat
• C. Animals contain no energy
• D. Meat is always unhealthy