Consumers and Decomposers — Reading Comprehension

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Grades

Standards

MS-LS2-3

About This Reader

This middle school science passage, aligned with NGSS standard MS-LS2-3, examines the essential roles of consumers and decomposers in ecosystems. Students will learn how consumers, including herbivores, carnivores, omnivores, and scavengers, obtain energy by feeding on other organisms. The text then explains how decomposers, such as bacteria and fungi, and detritivores like earthworms, break down dead matter and recycle nutrients back into the environment. By highlighting cause-and-effect relationships and integrating real-world examples, the passage helps students understand how these interactions support ecosystem health and stability. The resource includes differentiated versions, Spanish translations, a glossary, comprehension questions, writing prompts, and graphic organizers, all designed for grades 6-8. Audio integration supports diverse learners. This comprehensive set of materials builds scientific literacy and critical thinking about matter cycling in nature.

CONTENT PREVIEW

Consumer(Ecology)-1 — Illustration showing different types of consumers in an ecosystem

Ecosystems depend on complex interactions between living things to move energy and matter. In any forest, grassland, or pond, dead plants and animals do not simply pile up. Instead, a system of organisms—including consumers and decomposers—rapidly breaks down this material and keeps nutrients cycling. This cycle is essential for the health and stability of the entire ecosystem.

Consumers: Types and Functions
Consumers, also called heterotrophs, are organisms that cannot make their own food. Instead, they obtain energy by eating other organisms. There are several types of consumers. Herbivores eat only plants; examples include rabbits and deer. Carnivores eat only animals, such as wolves or hawks. Omnivores, like bears and humans, eat both plants and animals. Scavengers, such as vultures and hyenas, feed on dead animals. Each type of consumer plays a role in transferring energy through the food web. Scientists have studied food webs and found that, on average, only about 10% of energy is transferred from one level to the next, making the roles of consumers and decomposers even more critical for energy efficiency.

Decomposers and Detritivores: Recycling Matter
When plants and animals die, decomposers and detritivores begin their work. Decomposers—including bacteria and fungi—break down dead organic matter into simpler substances. Detritivores, like earthworms and millipedes, consume bits of dead material, further speeding up decomposition. This process returns essential nutrients such as nitrogen and phosphorus back to the soil, where they can be absorbed by plants. Without decomposers, nutrients would remain locked in dead matter, and new plant growth would eventually stop. Research has shown that in forests where decomposers are reduced, plant growth rates can drop by over 30%.

Interconnected Systems and Real-World Impact
Consumers and decomposers are connected in a continuous loop. When a carnivore dies, decomposers break down its body, and the nutrients help new plants grow. These plants then feed herbivores, and the cycle continues. Human activities, such as using pesticides or removing dead wood, can disrupt these cycles and threaten ecosystem balance. For example, if decomposer populations decline, soil fertility drops and food webs can collapse. Understanding these relationships helps scientists develop sustainable practices to protect our environment.

In summary, consumers and decomposers work together to keep ecosystems healthy. Consumers move energy through the food web, while decomposers recycle nutrients for new life. This ongoing exchange supports the survival of all organisms and connects to the greater principle of matter cycling in the biosphere.

Interesting Fact:
Some fungi can break down tough substances like plastic and oil, showing potential for cleaning up pollution as well as recycling nutrients in nature.

What is the main role of decomposers in an ecosystem?

Recycle nutrients from dead organismsProduce their own foodEat only plantsHunt living animals

Which of the following is an example of a scavenger?

VultureRabbitEarthwormMushroom

According to the passage, how much energy is typically transferred from one level to the next in a food web?

10%50%90%100%

What is a detritivore?

An organism that eats dead materialA plant that makes its own foodA consumer that eats only animalsA fungus that grows on trees

What might happen if there were no decomposers in an ecosystem?

Dead matter would build up and nutrients would not return to the soilPlants would grow fasterCarnivores would become herbivoresEnergy transfer would be more efficient

What does the term 'heterotroph' mean as used in the passage?

An organism that gets energy by eating othersA producer that makes its own foodA nutrient in the soilA type of fungus

How are decomposers and detritivores similar?

Both help break down dead matterBoth only eat living plantsBoth are scavengersBoth are carnivores

Why is the work of decomposers important for plant growth?

They return nutrients to the soil for plants to useThey eat all the plantsThey stop animals from eating plantsThey make the soil harder

True or False: Omnivores eat only plants.

TrueFalse

True or False: Fungi are a type of decomposer.

TrueFalse