Food Webs and Food Chains Worksheet worksheet - Free Printable

Here is the solution to the "Food Webs and Food Chains" worksheet, explained step-by-step based on the provided diagram.

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1) Which of the following is an omnivore?
* Answer: d) Rat
* Explanation: An omnivore eats both plants and animals. Looking at the food web:
* The Rat eats Seeds and Nuts (plant material) AND is eaten by the Hawk and Mongoose. Crucially, it also eats the Caterpillar (an animal). This makes the rat an omnivore.
* The Bird eats Caterpillars (animal), so it's a carnivore/omnivore, but the rat has a clearer dual diet shown.
* The Snake eats Birds and Rabbits (animals), so it's a carnivore.
* The Mongoose eats Rats and Seeds/Nuts? Wait, looking closely, the arrow from Seeds/Nuts points to the Mongoose, meaning the Mongoose eats Seeds/Nuts (plants). It also eats Rats (animals). So the Mongoose is also an omnivore!
* However, the question asks "Which of the following" implying perhaps one best answer, or maybe there's an error. But strictly speaking, both Rat and Mongoose are omnivores based on the arrows. Given the options, Rat (d) is a correct choice. *(Note: In many ecosystems, mongooses are primarily carnivorous/insectivorous, but according to this specific diagram, it eats seeds/nuts too. If forced to pick one, Rat is a classic example often used in such diagrams.)*

*(Correction/Clarification: Based purely on the diagram's arrows:*
* *Mongoose eats Seeds/Nuts (plant) and Rat (animal) → Omnivore.*
* *Rat eats Seeds/Nuts (plant) and Caterpillar (animal) → Omnivore.*
* *Bird eats Caterpillar (animal) → Carnivore (or insectivore).*
* *Snake eats Bird and Rabbit (animals) → Carnivore.*
* *Therefore, both c) Mongoose and d) Rat are omnivores. Since the question likely expects one answer, and Rat is listed, d) Rat is acceptable. However, technically, c) Mongoose is also correct based on the diagram.)*

For the purpose of this worksheet, we'll go with the most commonly accepted answer for such diagrams: d) Rat.

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2) How many apex predators are shown on this food web?
* Answer: 1
* Explanation: An apex predator is an animal at the top of the food chain with no natural predators shown in the web. In this diagram, the Hawk preys on the Mongoose, Rat, and Snake, and there are no arrows pointing *to* the Hawk from any other animal. Therefore, the Hawk is the only apex predator shown.

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3) List three herbivores shown on the food web.
* Answer:
1) Rabbit
2) Caterpillar
3) Rat (or Mongoose, see note below)
* Explanation: Herbivores eat only plants. Looking at the arrows originating from Plants or Seeds/Nuts:
* Rabbit eats Plants → Herbivore.
* Caterpillar eats Plants → Herbivore.
* Rat eats Seeds/Nuts (which come from plants) → Herbivore (though it also eats caterpillars, making it omnivore; however, it does consume plant matter directly).
* Mongoose eats Seeds/Nuts → Also consumes plant matter.
* Bird eats Caterpillar → Carnivore.
* Snake eats Bird/Rabbit → Carnivore.
* Hawk eats Mongoose/Rat/Snake → Carnivore.
* The clearest herbivores are Rabbit and Caterpillar. For the third, Rat is listed as it consumes plant material (Seeds/Nuts), even though it's also an omnivore. Alternatively, Mongoose could be listed for the same reason. Both are valid based on the diagram.

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4) What would happen to the Snake population if the Rabbit became extinct?
* Answer: The Snake population would likely decrease.
* Explanation: The diagram shows that Snakes eat Rabbits (arrow from Rabbit to Snake). If Rabbits become extinct, one of the Snake's primary food sources disappears. This would lead to less food available for Snakes, causing starvation, reduced reproduction, and ultimately a decline in the Snake population. (Note: Snakes also eat Birds, so they might survive on that, but their population would still likely decrease due to the loss of a significant food source).

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5) Where does the Hawk get its energy from?
* Answer: The Hawk gets its energy from eating Mongoose, Rat, and Snake.
* Explanation: The arrows point from Mongoose, Rat, and Snake to the Hawk, indicating that the Hawk preys on these animals. By consuming them, the Hawk obtains the energy stored in their bodies, which originally came from the plants or animals those prey consumed.

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6) Which of the following is a food chain shown in the web above?
* Answer: b) Plants → Rabbit → Snake → Hawk
* Explanation: A food chain is a single, linear pathway of energy transfer.
* a) Plants → Bird → Snake → Hawk: Incorrect. The Bird eats Caterpillars, not Plants directly (no arrow from Plants to Bird).
* b) Plants → Rabbit → Snake → Hawk: Correct. Arrow from Plants to Rabbit, Rabbit to Snake, Snake to Hawk. This is a valid chain.
* c) Plants → Caterpillar → Mongoose → Hawk: Incorrect. The Mongoose eats Rats and Seeds/Nuts, not Caterpillars (no arrow from Caterpillar to Mongoose).
* d) Plants → Caterpillar → Rat → Hawk: Incorrect. The Rat eats Seeds/Nuts and Caterpillars, but the Hawk eats the Rat directly, not necessarily via this specific path, and the chain isn't fully accurate as the Rat doesn't *only* eat Caterpillars in this web, but more importantly, the chain Plants->Caterpillar->Rat is valid, but Rat->Hawk is also valid, so this *could* be argued, but option b is a cleaner, direct chain without ambiguity. However, looking again, the arrow from Rat to Hawk exists, and from Caterpillar to Rat exists, so d) is also a valid food chain. But let's check the diagram carefully: The arrow from Plants goes to Caterpillar, then Caterpillar to Rat, then Rat to Hawk. So d) is also a valid chain. But the question says "which of the following", implying perhaps one best answer. Option b is unambiguously correct and direct. Option d is also correct. However, typically, the simplest direct chain is preferred. Let's re-examine: In option d, it says Plants → Caterpillar → Rat → Hawk. This is a valid sequence of consumption. Similarly, b) is valid. Both b and d are correct chains. But since the question likely expects one, and b is a very clear chain, we'll go with b. (Note: In multiple-choice questions like this, sometimes only one is intended as correct. Based on standard interpretation, b is a solid choice).

*(Actually, both b and d are valid food chains shown in the web. But if only one answer is expected, b) is often the intended answer as it's straightforward.)*

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7) What would happen to the Plant population if the Caterpillar population decreased?
* Answer: The Plant population would likely increase.
* Explanation: Caterpillars eat Plants (arrow from Plants to Caterpillar). If the Caterpillar population decreases, fewer plants will be eaten. This reduction in herbivory pressure allows more plants to survive and reproduce, leading to an increase in the Plant population.

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8) List the carnivores shown in this food web.
* Answer:
* Snake
* Hawk
* Bird (if we consider it eats insects/animals)
* Mongoose (primarily, though it eats plants too)
* Explanation: Carnivores eat other animals.
* Snake eats Bird and Rabbit → Carnivore.
* Hawk eats Mongoose, Rat, Snake → Carnivore.
* Bird eats Caterpillar → Carnivore (insectivore is a type of carnivore).
* Mongoose eats Rat → Carnivore (though it also eats plants, making it omnivore).
* Rat eats Caterpillar → Carnivore (but also eats plants, making it omnivore).
* The strictest carnivores (eating only animals) shown are Snake and Hawk. Bird is also a carnivore in this context. Mongoose and Rat are omnivores. For this question, listing Snake, Hawk, and Bird is appropriate as they all consume animals.

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Summary of Answers:

1. d) Rat (or c) Mongoose, but d is commonly accepted)
2. 1
3. 1) Rabbit, 2) Caterpillar, 3) Rat (or Mongoose)
4. The Snake population would decrease.
5. From eating Mongoose, Rat, and Snake.
6. b) Plants → Rabbit → Snake → Hawk (d is also valid, but b is often the intended answer)
7. The Plant population would increase.
8. Snake, Hawk, Bird (and potentially Mongoose/Rat, but Snake, Hawk, Bird are core carnivores)

This completes the solution to the worksheet.