B1.5.1 Energy in biomass

Question 1

What is the source of energy for most communities of living organisms?

Answer 1

Radiation from the Sun

Question 2

What organisms initially absorb radiation from the sun?

Answer 2

Green plants and algae absorb a small amount of the light that reaches them.

Question 3

What is the process that transfers light energy to chemical energy in plants called?

Answer 3

Photosynthesis.

Question 4

Where is chemical energy stored in plants?

Answer 4

In the substances that make up the cells of the plants (proteins, fats, carbohydrates, cellulose etc0

Question 5

What is biomass?

Answer 5

The mass of living material in an organism

Question 6

Describe the trend in biomass in a food chain?

Answer 6

The mass of living material (biomass) at each stage in a food chain is less than it was at the previous stage

Question 7

What does a pyramid of biomass show?

Answer 7

The biomass at each stage drawn to scale

Question 8

Why is the amount of energy contained in the biomass of organisms reduced at each successive stage in a food chain?
(5 marks)

Answer 8

• Each organism respires and uses some of the energy from their food to:
  - maintain body temperature
  - to move
• Some energy remains stored in the undigestable parts of the organism (feathers, bone, teeth, roots)
• some materials and energy are always lost in the organisms’ waste materials