Food Webs & Trophic Levels Study Guide

What is the primary source of energy for producers?

• The moon

• The sun

• Other producers

• Primary consumers

Answer explanation

The primary source of energy for producers, such as plants, is the sun. They use sunlight to perform photosynthesis, converting solar energy into chemical energy, which sustains their growth and the entire food web.

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What happens to energy as you move up the food pyramid?

• It increases

• It remains constant

• It decreases

• It doubles

Answer explanation

As you move up the food pyramid, energy decreases due to the loss of energy at each trophic level, primarily through metabolic processes and heat. Thus, the correct answer is that energy decreases.

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What is the main difference between a producer and a consumer?

• Producers make their own food, while consumers gather their own food.

• Producers eat other organisms, while consumers create energy.

• Producers rely on consumers for energy, while consumers rely on the sun.

• Producers and consumers both make their own food.

Answer explanation

The correct choice highlights that producers create their own food through processes like photosynthesis, while consumers obtain food by eating other organisms. This distinction is fundamental in understanding ecological roles.

Which of the following is an example of a producer?

• Lion

• Tree

• Rabbit

• Eagle

Answer explanation

A producer is an organism that can make its own food through photosynthesis. Trees are examples of producers as they convert sunlight into energy, while lions, rabbits, and eagles are consumers that rely on other organisms for food.

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What is the primary purpose of a decomposer in an ecosystem?

• To produce energy for plants

• To break down matter and enrich the soil

• To consume other organisms

• To create food chains

Answer explanation

The primary purpose of a decomposer is to break down dead organic matter, recycling nutrients back into the soil, which enriches it and supports plant growth. This process is essential for ecosystem health.

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What is the main difference between a food chain and a food web?

• A food chain is a single path, while a food web consists of multiple interconnected food chains.

• A food chain is stronger than a food web.

• A food web only includes plants, while a food chain includes animals.

• A food chain is more diverse than a food web.

Answer explanation

The main difference is that a food chain represents a single linear path of energy flow, while a food web illustrates the complex interconnections of multiple food chains within an ecosystem.

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Match each scenario with its effect on the food web.

• A key species goes extinct, disrupting the balance of the ecosystem.

• The food web remains unaffected

• A new predator is introduced, controlling an overpopulated species.

• The food web gains more diversity

• A minor species is removed, but other species fill its role.

• The food web becomes stronger

• Several new species migrate into the ecosystem.

• The food web becomes less stable

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Which of the following is an example of a consumer in an ecosystem?

• Plants

• Bacteria

• Animals

• Decomposers

Answer explanation

In an ecosystem, consumers are organisms that eat other organisms for energy. Animals are primary consumers, feeding on plants, or secondary consumers, feeding on other animals, making them clear examples of consumers.

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Why is diversity important in a food web?

• It makes the food web weaker.

• It ensures the food web is more stable and stronger.

• It reduces the number of food chains.

• It eliminates the need for decomposers.

Answer explanation

Diversity in a food web ensures that there are multiple species at each trophic level, which enhances stability and resilience. This means that if one species is affected, others can fill its role, making the food web stronger.

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What are autotrophs commonly called in the food web?

• Consumers

• Producers

• Apex predators

• Decomposers

Answer explanation

Autotrophs are organisms that produce their own food through photosynthesis or chemosynthesis. In the food web, they are commonly referred to as 'producers' because they create energy that supports other organisms.

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