10 minutes maximum! Can you do it in 5?
Q 1+2: The photograph shows some organisms living in a freshwater pond.
2. What is the correct match for each ecological term?
3-6. A food chain in the pond shown above could be ...
pond weed → small fish → frog → heron (small bird)
3. Which organism is a producer?
6. Energy transfer in a food chain is inefficient because some energy is converted into a form that cannot be passed on to the next trophic level. What are the two main ways this energy loss occurs?
7+8: A student is studying a type of snail on the sea shore:
How many snails would there be in 1 m2?
9-10. The diagram shows a food web of organisms found on a rocky shore:
Question 1:
In ecology, a population is defined as a group of organisms of the same species living in the same area at the same time.
The correct answer is: C. population ✅
*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret. Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.
Question 2:
A.
Community refers to all the living organisms of different species in an area. → All pond organisms matches this.
Population refers to all individuals of the same species in an area. → All carp fish in the pond is a single species example, so it matches.
Ecosystem includes both living organisms and their physical environment (water, rocks, soil, etc.). → The freshwater pond implies both biotic and abiotic components, so it matches.
The other options fail because:
B: Community = only plants (not all species); Ecosystem = only organisms (missing abiotic factors).
C: Community = only fish; Ecosystem = only water (incomplete).
D: Community = only birds; Population = all insects (multiple species, so that’s a community, not a population).
Question 3:
In a food chain, the producer is the organism that makes its own food through photosynthesis.
Here:
Pond weed → producer (autotroph)
Small fish → primary consumer
Frog → secondary consumer
Heron → tertiary consumer
✅ Correct answer: A. Pond weed
Question 4:
Carnivores are organisms that eat other animals (meat).
In the given food chain: Pond weed → small fish → frog → heron
Pond weed → producer (not a carnivore)
Small fish → eats pond weed (herbivore)
Frog → eats small fish (carnivore)
Heron → eats frog (carnivore)
So the carnivores are frog and heron.
✅ Correct answer: D. Frog and Heron
Question 5:
In almost all ecosystems, the original source of energy for the food chain is the Sun. Plants (producers) capture sunlight through photosynthesis and convert it into chemical energy, which then flows through the food chain.
✅ Correct answer: B. Sun
Question 6:
Answer: C – Energy is lost from the food chain primarily through respiration (which generates heat) and directly as heat itself, both of which are unavailable to subsequent trophic levels.
Question 7:
The apparatus shown in the typical exam-style image (student holding a rectangular frame on the seashore) is a quadrat. Quadrats are used to estimate population sizes by counting organisms within a known area.
The other options:
Tape measure – measures distance, not population size directly.
Callipers – measures size of individual organisms.
Transect – a line method (often used with quadrats), not an apparatus itself.
✅ Correct answer: B. Quadrat
Question 8:
Let’s calculate step by step.
Sampling area = 25 cm×25 cm=625 cm2
Convert to m2 1 m2=10,000 cm2
Scaling factor from sampling area to 1 m2 10,000/625 = 16
Snails in 1 m2: 20 snails×16=320 snails
✅ Correct answer: D. 320
Question 9:
The correct answer is B. Barnacles and Top Shells.
Question 10:
If whelks no longer have access to top shells, they'll feed on more barnacles. So the correct answer is D, Barnacle numbers decrease.