ROUND 2 SPEED RACE
ONE EIGHTH STAGE 2026
Contest 1
Prempeh College: 66
West Africa SHS: 30
Kumasi Girls’ SHS: 19
Contest 2
Keta SHTS: 56
Kadjebi Asato SHS: 28
Anum Presby SHS: 19
Contest 3
Ghana National College: 38
St. Monica’s SHS: 22
Presby SHS, Suhum: 16
QUESTION
What type of ecological pyramid represents the total dry weight of organisms at each trophic level?
ANSWER: Pyramid of biomass
EXPLANATION
A pyramid of numbers counts individual organisms, while a pyramid of biomass instead measures the total dry mass of living material at each trophic level, giving a better picture of the actual "amount of life" at each stage of a food chain.
PRACTICE QUESTIONS
1. What is biomass?
ANSWER: The total mass of living material in an area or trophic level.
2. What does a pyramid of numbers show?
ANSWER: The number of organisms at each trophic level.
3. What does a pyramid of energy show?
ANSWER: The energy at each trophic level.
4. Why can a biomass pyramid be inverted in the ocean?
ANSWER: Phytoplankton grow and are eaten so fast that their standing biomass is small.
5. In what units is biomass usually measured?
ANSWER: Grams of dry mass per square metre.
6. Which organisms are at the first trophic level?
ANSWER: Producers.
7. How is dry mass found?
ANSWER: By drying the organisms in an oven until the mass is constant.
8. Why is dry mass used instead of fresh mass?
ANSWER: The water content varies.
9. What is the standing crop?
ANSWER: The total biomass present at one time.
10. Give an example of an inverted pyramid of numbers.
ANSWER: A single tree supporting many insects.
11. Which pyramid is never inverted?
ANSWER: The pyramid of energy.
12. What is productivity?
ANSWER: The rate at which biomass or energy is produced.