Question
The three-toed sloth, Bradypus variegatus, lives in tree tops where it feeds on leaves. It also feeds on algae and fungi which live in its fur.
In which trophic group should the three-toed sloth be classified?
A. Autotroph
B. Consumer
C. Detritivore
D. Saprotroph
▶️Answer/Explanation
Answer: B. Consumer
Explanation:
The three-toed sloth (Bradypus variegatus):
- Feeds on leaves → These are living plant materials.
- Feeds on algae and fungi in its fur → These are also living organisms (or recently alive).
Trophic Group Analysis:
A. Autotroph
Incorrect: Autotrophs make their own food through photosynthesis or chemosynthesis (e.g., plants, algae). The sloth does not produce its own food.
B. Consumer
Correct: Consumers eat other living organisms. Since the sloth eats leaves, algae, and fungi, it fits into this group.
C. Detritivore
Incorrect: Detritivores eat non-living organic matter (dead material). The sloth feeds on living organisms, not detritus.
D. Saprotroph
Incorrect: Saprotrophs (like fungi and bacteria) externally digest dead organic matter and absorb nutrients. The sloth does not externally digest anything.
Question
The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.
Which organism is a tertiary consumer?
A. Organism T
B. Organism U
C. Organism W
D. Organism Y
▶️Answer/Explanation
Answer: B. Organism U
Explanation:
A tertiary consumer eats a secondary consumer, which eats a primary consumer, which eats a producer.
Step-by-step breakdown:
Producers (e.g., R, S, T): No incoming arrows → they produce energy, not consume others.
Primary Consumer (e.g., W): Eats producers (R, S, T) → gets energy directly from plants/algae.
Secondary Consumers (e.g., V, X, Y): Eat primary consumer (W).
Tertiary Consumers: Eat secondary consumers: U eats V, Z eats X and Y
Option Analysis:
A. T → A producer.
B. U → Eats V, a secondary consumer → tertiary consumer
C. W → Eats producers → primary consumer
D. Y → Eats W → secondary consumer
Question
The table contains information about the diet of some animals.
| Animal | Diet |
| Snakes | Mice |
| Eagles | Snakes |
| Mice | Seeds |
Which pyramid of energy represents this information?
Answer/Explanation
Answer: C
Explanation:
What is a Pyramid of Energy?
A pyramid of energy shows how energy is passed along a food chain from the bottom (producers) to the top (predators). As you move up the pyramid, energy decreases, because:
- Only a small amount of energy (about 10%) is passed to the next level.
- Most energy is lost as heat, movement, or waste.
So, the bottom level has the most energy, and the top level has the least.
Food Chain Given:
From the diet table:
- Mice eat seeds → Mice are primary consumers
- Snakes eat mice → Snakes are secondary consumers
- Eagles eat snakes → Eagles are top predators
- Seeds are producers
So, the correct food chain is Seeds → Mice → Snakes → Eagles
Building the Energy Pyramid:
We build it from bottom to top:
- Seeds (Producers – most energy)
- Mice (Primary consumers)
- Snakes (Secondary consumers)
- Eagles (Top predators – least energy)
Each step up has less energy, so each block gets narrower.
Why Option C is Correct:
- The levels are in the correct order: Seeds → Mice → Snakes → Eagles
- The shape is correct: A true pyramid, widest at the bottom, narrowing at the top — showing energy decreasing at each level.
This is exactly how an energy pyramid should look.
Why Others Are Wrong:
A: Order is reversed (top to bottom is wrong)
B: Order is right, but the pyramid shape is upside down (energy increases going up, which is incorrect)
D: Has the right order, but Eagles (top predators) have the widest block, which is not realistic they get the least energy.