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Predators and Scavengers of Savanna — Reading Comprehension

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MS-LS2-1
MS-LS2-2
MS-LS2-4

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This comprehensive science passage introduces middle school students to the vital roles of predators and scavengers in ecosystems, aligning with NGSS MS-LS2-1, MS-LS2-2, and MS-LS2-4. Students will learn how predators control populations, how scavengers recycle nutrients, and how these interactions maintain ecosystem balance. With a direct, phenomenon-based introduction and mechanistic explanations, the passage connects biological concepts such as energy flow, food webs, and decomposition. Real-world examples include wolves, vultures, and crabs, with quantitative information about nutrient cycling. The resource includes a glossary, Spanish translation, differentiated text for struggling readers, quiz, writing prompts, and graphic organizers. Audio integration supports diverse learners. This resource is ideal for classroom or independent study and provides engaging, standards-based content for grades 6-8.

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Camouflage (Unsplash) — Masai Mara Game Reserve, Kenya by Lisa H / Wikimedia Commons (CC0).

Predators and scavengers play essential roles in every ecosystem. When a wolf hunts a deer or a vulture feeds on an animal carcass, these actions affect many other living things in their environment. The presence of these organisms helps maintain the balance of plant and animal populations, supporting the health of the entire ecosystem. Understanding how predators and scavengers interact with their surroundings reveals important cause-and-effect relationships within the natural world.

How Predators Control Populations

A predator is an organism that hunts, captures, and consumes other animals, known as prey. Wolves are classic examples of predators, preying on deer, elk, and smaller mammals. When wolves hunt deer, they reduce the number of deer in the population. This prevents overgrazing, which can damage plants and soil. In some regions, when predators are removed, prey populations can increase by over 50%, leading to ecosystem imbalance. Predators often target weaker or sick animals, which helps keep prey populations healthier. These actions demonstrate a chain of effects: predator presence → fewer prey animals → healthier plant life → more stable habitats for other species.

The Role of Scavengers in Nutrient Cycling

Scavengers are organisms that feed on dead or decaying animals. Unlike predators, scavengers such as vultures, hyenas, and crabs do not hunt live prey. Instead, they consume remains left behind by predators or natural deaths. This process, called decomposition, is vital for recycling nutrients back into the ecosystem. When a vulture eats a carcass, it breaks down tissues that would otherwise rot and attract harmful bacteria. Research shows that vultures can remove up to 70% of carrion in some habitats, reducing disease spread and promoting soil fertility. Scavengers work together with decomposers like bacteria and fungi, completing the nutrient cycle by breaking down what remains even further.

Interactions and Ecosystem Balance

Predators and scavengers are linked in food webs. After a predator like a wolf kills an animal, scavengers arrive to consume the leftovers. This interaction ensures that energy and nutrients are not wasted. In coastal areas, crabs and gulls act as both predators and scavengers, depending on food availability. Human activities, such as removing top predators or poisoning scavenger species, can disrupt these relationships. For example, the decline of vulture populations in India led to increased disease because more carcasses were left to rot, showing the importance of every link in the ecosystem.

Predators and scavengers demonstrate how living things are interconnected. By controlling populations and recycling nutrients, they help keep ecosystems healthy and resilient. These roles illustrate broader scientific principles, such as energy transfer, matter cycling, and the stability of complex systems. As scientists continue to study these organisms, they uncover deeper connections that guide conservation and ecosystem management strategies.

Interesting Fact:
Vultures have stomach acid strong enough to dissolve anthrax and rabies viruses, making them nature’s disease control experts!

What is the main role of a predator in an ecosystem?

To hunt and eat other animalsTo clean up dead materialTo produce food from sunlightTo break down plant matter

Which organism is a scavenger?

WolfVultureElkDeer

What happens to prey populations if predators are removed?

Prey populations decreasePrey populations stay the samePrey populations increasePredators increase

What is 'decomposition' as described in the passage?

The process of hunting live animalsThe process of breaking down dead materialThe process of growing plantsThe process of building habitats

In the passage, which word best describes an animal hunted by a predator?

ScavengerDecomposerPreyCarrion

What is the effect of vultures removing up to 70% of carrion in their habitats?