Texas TEKS5th GradeScience

5.12B— Predicting Ecosystem Change in Food Webs

Organisms and environments · b.12: Organisms and environments. The student describes patterns, cycles, systems, and relationships within environments. The student is expected to:

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What this standard means: TEKS §112.7.12.B asks fifth graders to predict how a change in an ecosystem affects the flow of energy and cycling of matter through a food web. This intervention, Texas Food Web Changes, practices that skill with short-answer questions set in real Texas habitats: a prairie drought that reduces grasses, an invasive plant crowding out gulf coast producers, and a pesticide runoff event that lowers insect numbers in a marsh. Students trace the effect from producer to consumer to decomposer, naming which organism is affected first and what change follows next, in one to three sentences. With repetition, tracing a disturbance step by step through a food web replaces guessing at the end result.

What the standard says, word for word · §112.7.b.12.B

predict how changes in the ecosystem affect the cycling of matter and flow of energy in a food web;

Read it at the source: Texas Education Agency (TEA)

What’s inside

What you get, and who it’s for

Everything below is measured from the actual lesson and the actual file. Nothing here is an estimate.

Time to run: About 25 minutes. 7 min lesson, then 18 min of practice.
In the download: 9 printable pages: the full lesson, the worked examples, the visual models, and 6 practice questions with space to work. An educator answer key is included at the end, so the student pages come first and it is still ready to hand out. The lesson’s worked examples do show their solutions, because that is how they teach.
Question set: The download carries all 6 questions. The page shows 6 of them as a sample.
Question format: Every question is short answer. Students show their work on the page.
Assumed before this: Students who are shaky on these will struggle with 5.12B. Worth a quick check first.
§112.6.b.12.B(Grade 4) Students need to know that a food web shows energy moving from producers to consumers and that decomposers break down dead plants and animals. They should also be able to identify producers, consumers, and decomposers in a simple ecosystem.
Dates: Published August 6, 2026. Last updated August 14, 2026.

The sample intervention

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5.12B

Texas Food Web Changes: Predicting What Happens Next

Predict how a change in an ecosystem affects the cycling of matter and the flow of energy in a food web.

Read the passages and examples below to learn about predicting how ecosystem changes affect energy transfer and matter cycling in a food web. Think about producers, consumers, decomposers, and what happens next when one part of the ecosystem changes.

A food web shows who eats whom in a habitat. Energy starts with producers, like grasses or algae, because they make their own food using sunlight. Consumers get energy by eating plants or animals. Decomposers, such as fungi and bacteria, break down dead matter and return nutrients to the soil or water. That keeps matter cycling through the ecosystem.

Texas prairie food web

sun
producer
consumer
decomposer

Each arrow shows which way energy moves. Follow the arrows to predict what happens next when one part changes.

When one part of a food web changes, the effects can spread. If a producer is lost, less energy enters the web, so plant-eating consumers may decline first. Then animals that eat those consumers may also decline. If a consumer becomes too common, it may use up more food, which can change other populations too. In every case, energy transfer becomes weaker or shifts to a different path.

Texas ecosystems can change in many ways, such as drought in the prairie, invasive species along the gulf coast, or fewer plants in the hill country. A drought can reduce grasses, which lowers energy for prairie dogs and then for coyotes or hawks. An invasive species may crowd out native producers, changing what consumers can eat. Even when living things decline, decomposers still help recycle matter from dead plants and animals.

Gulf Coast marsh food web

producer
consumer
decomposer

Arrows show which way energy moves. Trace two steps from any change to predict what happens next.

To predict an effect, follow the path of energy and matter through the food web. Name the first organism affected, then explain the next change that follows. Use the words producer, consumer, decomposer, energy transfer, and matter cycling when they fit. Strong predictions show how one disturbance can cause two connected changes in the ecosystem.

Matter cycles back to the start

Energy flows one way through a food web, but matter keeps cycling. A change at one stage changes the whole loop.

Worked exampleIf drought reduces prairie grass, prairie dogs may decline because less energy reaches them through the food web, and coyotes may then decline because they have less prey.

Worked exampleIf an invasive plant crowds out gulf coast producers, fewer herbivores may survive, and decomposers may later break down less dead plant matter from that area.

Worked exampleIf a hill country producer disappears, consumers that depend on it lose energy first, and the food web may become smaller as matter keeps cycling more slowly through dead plants and animals.

Practice questions

1
In a prairie, drought reduces the grasses. Predict two changes that may happen next in the food web, and explain why.
2
A student says this about a gulf coast food web: 'If an invasive plant crowds out native producers, decomposers stop helping because the food web breaks.' What is wrong with that idea?
3
In a Gulf Coast marsh, a pesticide runoff event lowers the number of insects living in the reeds. Small fish and frogs eat those insects, and herons and coyotes may eat the fish or frogs. Explain how this change could affect the coyote population and the rest of the food web.
4
A food web in the gulf coast has this pattern: algae make food, small fish eat algae, larger fish eat small fish, and decomposers break down dead matter. A storm damages many algae. What does this model show will happen first, and why?
5
A drought in a Texas prairie reduces prairie dog populations, and fewer grasses grow back after grazing. Explain how these changes could affect coyotes and other organisms in the food web. Use the words consumer and energy transfer in your answer.
6
In a hill country habitat, fewer native plants survive after a dry season. Predict one change in a consumer population and one change in matter cycling after those plants die.

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Watch for this

Common mistakes

Single-Step Thinking Students often think a change in one part of a food web only affects that one organism, or they forget that decomposers keep working after plants or animals die. In this skill, the bigger mistake is stopping after the first change instead of tracing what happens next to consumers, predators, and matter cycling through the ecosystem.

Vocabulary

Key terms

producer: A producer is a living thing, like a grass or algae, that makes its own food using sunlight.
consumer: A consumer gets energy by eating plants or animals.
decomposer: A decomposer, such as fungi or bacteria, breaks down dead matter and returns nutrients to the soil or water.
food web: A food web shows who eats whom in a habitat.

In the classroom

How to use this intervention

Use the 7-minute lesson as a brief whole-class warm-up to read the passages and model how to trace a change through a food web. Then use the 18-minute practice time for independent work or a small group, with teacher check-ins to support students as they explain the first organism affected and the next change that follows.

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Questions educators ask

Educator FAQ

What grade is this worksheet for?

This worksheet is for Grade 5.

Which TEKS standard does it align to?

It aligns to TEKS §112.7.b.12.B, which asks students to predict how changes in an ecosystem affect the cycling of matter and the flow of energy.

Is an answer key included?

Yes, the free worksheet PDF includes all questions with a complete answer key.