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Climate Change: Vulnerable Ecosystems — Reading Comprehension

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MS-ESS3-5
MS-LS2-4

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This middle school science passage, aligned with NGSS standards MS-ESS3-5 and MS-LS2-4, helps students understand how climate change impacts some of the most vulnerable ecosystems on Earth. Students will learn mechanisms behind climate-driven changes in the Arctic, mountains, coral reefs, tropical cloud forests, and low-lying islands. The text explains scientific concepts such as permafrost thaw, ocean acidification, species migration, and fire frequency, while also providing real-world quantitative data and cause-and-effect relationships. Glossary terms, a differentiated reading level version, and Spanish translations make this resource accessible for diverse learners. Assessment activities, writing prompts, and graphic organizers support critical thinking and comprehension. Audio integration is available to further support students. This resource is ideal for grades 6-8 life and Earth science units focusing on environmental change, systems thinking, and human impacts.

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Explore a stunning underwater scene featuring a vibrant sea fan among coral reefs, showcasing marine biodiversity. — Coral reefs are often called the “rainforests of the sea” due to their rich biodiversity. Image by Tom Fisk / Pexels.

Climate change is causing rapid and observable changes in Earth's ecosystems. The effects are not felt equally across the planet. Certain ecosystems are especially vulnerable because they depend on specific temperature ranges, water sources, or other delicate balances. Scientists study these threatened areas to understand how complex systems respond to environmental changes and what this means for the future of life on Earth.

Mechanisms of Ecosystem Vulnerability
Polar regions are among the most vulnerable. The Arctic is warming two to three times faster than the global average, a process called Arctic amplification. This leads to dramatic sea ice loss. Permafrost, permanently frozen ground, is thawing and releasing stored carbon into the atmosphere. Species such as polar bears, seals, and walruses rely on sea ice for hunting and breeding. As the ice shrinks, their populations decline. In alpine and mountain ecosystems, plants and animals move upward to escape warming temperatures. However, as they reach the peaks, there is “nowhere to go,” leading to potential local extinctions. Melting glaciers reduce water supplies for millions of people and animals downstream.

Coral Reefs, Cloud Forests, and Islands
Coral reefs are often called the “rainforests of the sea” due to their rich biodiversity. They are extremely sensitive to temperature changes. When ocean temperatures rise, corals expel the algae that live inside them, causing bleaching and sometimes death. Over 50% of coral reefs have already experienced bleaching events, and some scientists predict that most could disappear by 2050 if warming continues. Ocean acidification, caused by increased carbon dioxide, makes it harder for corals to build their skeletons. Tropical cloud forests, such as those in Central and South America, depend on consistent cloud cover. Drier conditions from climate change threaten species found nowhere else, called endemic species. Low-lying islands, like the Maldives and Tuvalu, face rising sea levels that could submerge entire communities.

Fire, Tundra, and the Global System
Mediterranean-type ecosystems, such as parts of California and Australia, are experiencing more frequent and intense wildfires due to higher temperatures and drier conditions. In the tundra, warming happens faster than plants can migrate. Thawing permafrost releases ancient carbon, which increases greenhouse gases and creates a feedback loop, speeding up climate change. Scientists use satellite data, field observations, and computer models to study these changes and predict future impacts. Understanding these systems helps us make informed decisions about conservation and climate solutions.

Protecting vulnerable ecosystems is not just about saving plants and animals. These areas provide food, water, and climate stability for humans as well. The fate of these systems is deeply connected to our own future on Earth.

Interesting Fact: Some Arctic regions have warmed by more than 4°C (7°F) since 1900, far exceeding the global average.

Which region is warming two to three times faster than the global average?

The ArcticThe MediterraneanThe Amazon RainforestThe Sahara Desert

What is the primary cause of coral bleaching?

Colder water temperaturesRising ocean temperaturesToo much sunlightOverfishing

What is permafrost?

Frozen ocean waterGround that stays frozen for yearsIce on mountain peaksA type of seaweed

What happens when permafrost thaws?

It forms new glaciersIt releases stored carbon to the atmosphereIt increases ocean salinityIt creates more sea ice

In the passage, what does 'endemic' mean?

A species found everywhereA species only found in one placeA migrating speciesA species that eats many things

Which is an example of a feedback loop from the passage?

Coral reefs supporting many fishMelting glaciers providing waterThawing permafrost releasing carbon, which increases warmingPolar bears hunting on sea ice

Why are alpine species at risk from climate change?

They can move to cooler areas belowThey have nowhere else to go once they reach the topThey are not affected by temperatureThey only live in the ocean

How does ocean acidification affect coral reefs?

It makes it easier for corals to build skeletonsIt helps corals grow fasterIt makes it harder for corals to build skeletonsIt keeps the water cooler

True or False: Low-lying islands are at risk of being submerged because of rising sea levels.

TrueFalse

True or False: Mediterranean-type ecosystems are becoming less likely to experience wildfires due to climate change.

TrueFalse