Lesson 12: Pyramids of Biomass/ Trophic Levels

Question 1

What do pyramids of biomass actually represent?

Answer 1

• Pyramids of biomass represent the relative amount of biomass in each level of a food chain.

Question 2

True or False

Trophic level 4 is at the bottom of a pyramid of biomass.

Answer 2

• False.
• Trophic level 1 is at the bottom of a pyramid of biomass.

Question 3

How much of incident light (on algae/ plants) is transferred to be used for photosynthesis?

Answer 3

• Only 1%.

Question 4

How much percentage biomass is transferred from one trophic level to the next?

Answer 4

• Only approx 10%

Question 5

What are the reasons as to why biomass is lost between trophic levels in a food chain?

Answer 5

• Not all the ingested material is absorbed, some is egested as faeces
• Some absorbed material is lost as waste, such as carbon dioxide and
  water in respiration and water and urea in urine.

Question 6

True or False

Small amounts of glucose are used in respiration.

Answer 6

• False.
• Large amounts of glucose are used in respiration.

Question 7

What is the number of organisms at each trophic level like?

Answer 7

• Number of organisms at each trophic level decreases (going from Trophic Level 1 to Trophic Level 4 .)

Question 8

True or False

When measuring biomass, scientists use live animals.

Answer 8

• False.
• Kill and dry animals and weigh biomass

Question 9

How many levels of trophic levels are there?

Answer 9

• 4.

Question 10

What organisms are in Level 1 trophic level in a food chain? What are these organisms known as?

Answer 10

• Plants and algae (make their own food - known as producers.)

Question 11

What organisms are in level 2 trophic level of food chain? What are these organisms known as?

Answer 11

• Herbivores that eat plants/ algae (are known as primary consumers.)

Question 12

What organisms are on level 3 trophic level? What are these organisms known as?

Answer 12

• Carnivores that eat herbivores.
• Known as secondary consumers.

Question 13

What organisms are on level 4 trophic level? What are these organisms known as?

Answer 13

• Carnivores that eat other carnivores (known as tertiary consumers.)
• Apex predators are carnivores with no predators.

Question 14

What are Apex predators?

Answer 14

• Apex predators are carnivores with no predators.

Question 15

How do decomposers break down plant and animal matter?

Answer 15

• Decomposers break down dead plant and animal matter by secreting enzymes into the environment.
• Small soluble food molecules (from the plant/ animal matter) then diffuse into the micro-organism.