Food Chains Food Webs and Energy Pyramid Worksheets - Free Pintables - Free Printable

Let's solve each part of the Food Chains, Food Webs, and Energy Pyramid Worksheet step by step.

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1. Complete the energy pyramid

We are given:
- The base has 5000 units of energy.
- The 10% rule applies: Only 10% of energy is transferred from one trophic level to the next.
- The rest (90%) is used in metabolism or lost as heat.

#### Step-by-step energy calculation:

- Producer level (bottom): 5000 units
- Primary consumer level: 10% of 5000 = 0.10 × 5000 = 500 units
- Secondary consumer level: 10% of 500 = 0.10 × 500 = 50 units
- Tertiary consumer level: 10% of 50 = 0.10 × 50 = 5 units

So, fill in the pyramid from bottom to top:

```
Tertiary Consumer → 5 Units of Energy
Secondary Consumer → 50 Units of Energy
Primary Consumer → 500 Units of Energy
Producer → 5000 Units of Energy
```

Now, label the trophic levels on the left side:

- Bottom: Producer
- Next: Primary Consumer
- Then: Secondary Consumer
- Top: Tertiary Consumer

Also, complete the sentence:

> The 10% rule of energy transfer states that each level in an ecosystem transfers only 10% of its energy to the levels above it. The rest 90% is used in metabolism or lost as heat.

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2. Analyze the food web

Here’s the food web with arrows showing who eats whom:

- Green Plant → Rabbit, Goat, Mouse
- Rabbit → Owl, Wild Cat, Jackal
- Goat → Lion, Jackal
- Mouse → Snake, Owl
- Snake → Kite
- Owl → Kite
- Wild Cat → Lion
- Jackal → Lion
- Kite → Lion

Now answer the questions:

#### a) Name the producer.
✔ Green Plant
(Producers make their own food via photosynthesis.)

#### b) Name three primary consumers.
Primary consumers eat producers (plants).

✔ Rabbit, Goat, Mouse

#### c) Name one secondary consumer.
Secondary consumers eat primary consumers.

Examples:
- Owl (eats rabbit/mouse)
- Snake (eats mouse)
- Wild Cat (eats rabbit)
- Jackal (eats rabbit/goat)

✔ Any one of these is correct. Let’s pick: Owl

#### d) Name one apex predator.
Apex predators are at the top of the food chain; they have no natural predators.

✔ Lion (it eats other animals but is not eaten by others in this web)

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3. Fill in the blanks

> There are five main trophic levels in a food chain. They are producer, primary consumer, secondary consumer, tertiary consumer, and quaternary consumer. A food chain starts with a producer and ends with a consumer.

Note: Some textbooks list only four levels, but commonly five are recognized. However, often the last two are grouped as "top carnivores" or "apex predators."

But since the question says “main trophic levels,” the standard ones are:

- Producer
- Primary consumer
- Secondary consumer
- Tertiary consumer
- Quaternary consumer (optional, but included here for completeness)

However, many curricula use just four: Producer → Primary → Secondary → Tertiary.

But let’s go with five if possible.

Alternatively, if you're following common standards:

> There are four main trophic levels in a food chain. They are producer, primary consumer, secondary consumer, and tertiary consumer. A food chain starts with a producer and ends with a top predator or consumer.

But based on the pyramid earlier (with four levels), we can say:

✔ Four main trophic levels: producer, primary consumer, secondary consumer, tertiary consumer.

And: A food chain starts with a producer and ends with a consumer (or top predator).

Final version:

> There are four main trophic levels in a food chain. They are producer, primary consumer, secondary consumer, and tertiary consumer. A food chain starts with a producer and ends with a consumer.

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✔ Final Answers:

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#### 1. Energy Pyramid

| Trophic Level | Units of Energy |
|------------------------|------------------|
| Producer | 5000 |
| Primary Consumer | 500 |
| Secondary Consumer | 50 |
| Tertiary Consumer | 5 |

Sentence:
> The 10% rule of energy transfer states that each level in an ecosystem transfers only 10% of its energy to the levels above it. The rest 90% is used in metabolism or lost as heat.

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#### 2. Food Web Questions

a) Producer: Green Plant
b) Three primary consumers: Rabbit, Goat, Mouse
c) One secondary consumer: Owl (or Snake, Wild Cat, Jackal)
d) One apex predator: Lion

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#### 3. Fill in the Blanks

> There are four main trophic levels in a food chain. They are producer, primary consumer, secondary consumer, and tertiary consumer. A food chain starts with a producer and ends with a consumer.

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