12th grade ecosystems and food chains

Question 1

Producers in a field store 40000 kJ/m² of energy per year. Primary consumers gain 3200 kJ/m². What is the efficiency of energy transfer, in %?

Answer %

Question 2

Why is eating plant foods often more energy-efficient for feeding people than eating meat?

• A. Animals photosynthesise
• B. Fewer trophic levels means less energy is lost before it reaches people
• C. Meat contains no protein
• D. Plants contain no energy

Question 3

Producers capture 200000 kJ. 20 % is passed to primary consumers and 5 % of that is passed to secondary consumers. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 4

Producers in a field store 10000 kJ/m² of energy per year. Primary consumers gain 1000 kJ/m². What is the efficiency of energy transfer, in %?

Answer %

Question 5

Why are food chains rarely longer than 4 or 5 levels?

• A. Too little energy is left to support another level
• B. There are not enough species on Earth
• C. Animals refuse to eat higher animals
• D. Plants stop growing

Question 6

Producers capture 500000 kJ. 20 % is passed to primary consumers and 5 % of that is passed to secondary consumers. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 7

Producers in a field store 10000 kJ/m² of energy per year. Primary consumers gain 500 kJ/m². What is the efficiency of energy transfer, in %?

Answer %

Question 8

Pyramids of biomass are usually pyramid-shaped. Why?

• A. Less biomass can be supported at each higher level because energy is lost
• B. It is just how they are drawn
• C. Predators are always smaller than prey
• D. Producers are always heavier individually

Question 9

Producers capture 1000000 kJ. 20 % is passed to primary consumers and 5 % of that is passed to secondary consumers. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 10

Producers in a field store 10000 kJ/m² of energy per year. Primary consumers gain 800 kJ/m². What is the efficiency of energy transfer, in %?

Answer %

Question 11

Why is eating plant foods often more energy-efficient for feeding people than eating meat?

• A. Meat contains no protein
• B. Plants contain no energy
• C. Animals photosynthesise
• D. Fewer trophic levels means less energy is lost before it reaches people

Question 12

Producers capture 100000 kJ. 20 % is passed to primary consumers and 10 % of that is passed to secondary consumers. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 13

Producers in a field store 40000 kJ/m² of energy per year. Primary consumers gain 4800 kJ/m². What is the efficiency of energy transfer, in %?

Answer %

Question 14

Why is energy transfer between trophic levels inefficient?

• A. Energy is destroyed at each level
• B. Much is used in respiration and lost as heat, and some material is not eaten or digested
• C. Consumers photosynthesise
• D. Predators eat too much

Question 15

Producers capture 200000 kJ. 20 % is passed to primary consumers and 5 % of that is passed to secondary consumers. How much energy reaches the secondary consumers, in kJ?

Answer kJ

Question 16

Producers in a field store 20000 kJ/m² of energy per year. Primary consumers gain 4000 kJ/m². What is the efficiency of energy transfer, in %?

Answer %