B4.1.4 Pyramids of Biomass

Question 1

Pros/cons of food chains

Answer 1

Pro- shows flow of biomass through community
Con- doesn’t show number of organisms involved
- doesn’t show size of biomass transfer

Question 2

Organisation of pyramid of biomass

Answer 2

Base = produce

Going up = trophic levels going up

Question 3

What usually happens as you move up a pyramid of biomass?

Answer 3

Size of organism increases, but number decreases

Question 4

How to calculate biomass

Answer 4

• take samples of organisms from each trophic level

- measure average mass and multiply by number of organisms present

Question 5

Which mass?

Answer 5

Dry mass as water content can vary between individuals

Dry mass = organism killed and dried in a kiln

Question 6

How to draw pyramid of biomass?

Answer 6

1. Width of bar = biomass of organisms at trophic level
2. Decide on scale (eg. 1cm = 10kg)
3. Height of each bar is same