Week 3: Climate Change Impact on Ecosystems
Grade 7 Science | Rosche
MS-LS2-5 Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
The Phenomenon: Why are coral reefs dying even in protected areas?
Cycle 8 Assessment — Climate Change Impact on Ecosystems
Why are coral reefs dying even in protected areas?
Cognate Strategy: Many science words look similar in English and Spanish — use your Spanish to learn science!
| Term | Spanish | Definition |
|---|---|---|
| climate change | cambio climatico | Long-term shifts in global temperature and precipitation patterns |
| global warming | calentamiento global | Increase in average global temperature from greenhouse gases |
| greenhouse gas | gas de efecto invernadero | Gas that traps heat in atmosphere like CO2 and methane |
| methane | metano | Potent greenhouse gas from livestock and wetlands |
| species range | rango de especies | Geographic area where a species naturally occurs |
| coral bleaching | blanqueamiento de coral | Loss of symbiotic algae from corals due to heat stress |
| extreme weather | clima extremo | Unusual, severe weather events like hurricanes and heat waves |
| drought | sequía | Extended period of abnormally low rainfall |
| heat wave | onda de calor | Prolonged period of excessively hot weather |
Part 1 — Synthesis Review
Review and synthesize key concepts from Weeks 1 and 2 before the cumulative assessment.
Part 1 — Synthesis Review (20 pts | ~15 min)
Before you begin the cumulative assessment, spend 15 minutes reviewing the core concepts from Weeks 1 and 2. This review helps activate your memory and prepares you to make connections across the full Cycle 8 content.
Key Ideas to Review
- Week 1: Trophic cascades — how changes to one trophic level ripple through an ecosystem (Yellowstone wolves → elk → vegetation → rivers)
- Week 1: Keystone species — species with outsized ecosystem effects; ecology of fear
- Week 2: Biodiversity-stability relationship — high biodiversity = faster recovery from disturbance
- Week 2: Functional redundancy — biodiversity as insurance against ecosystem collapse
- Cross-cutting: Stability and Change (CCC-7); Cause and Effect (CCC-2)
Open the Part 1 Form
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Worked Example – How to Argue Climate Cause from Ecosystem Data
1
Worked Example: Arguing Climate as a Cause of Coral Decline
Assessment context: Part 2 will ask you to evaluate data sets and argue for or against climate change as the primary cause of coral reef decline in a marine protected area (MPA). Here is how to structure that argument.
Step 1: Identify competing explanations
- Climate hypothesis: Rising ocean temperatures disrupt the coral-zooxanthellae symbiosis, causing bleaching even in protected areas with no local pollution.
- Local stressor hypothesis: Pollution, overfishing, and runoff cause decline — not global climate. Protected areas should show recovery if climate is not the cause.
Step 2: Use the data to decide
Step 3: Write your CER
Evidence: Cite at least 2 specific data points from the graphs (temperature anomalies, bleaching %, recovery rates).
Reasoning: Explain how your evidence supports your claim using the coral-zooxanthellae symbiosis mechanism (MS-LS2-5).
Part 2 — Cumulative Assessment
Cumulative assessment covering Cycle 8 ecosystem dynamics and biodiversity concepts.
Part 2 — Cumulative Assessment (60 pts | ~40 min)
This is the main cumulative assessment for Cycle 8. It covers ecosystem dynamics (W1), biodiversity and resilience (W2), and climate change impacts on ecosystems (W3 content). Sections A–D span multiple-choice, short answer, data analysis, and a CER argument.
Assessment Structure
- Section A (15 pts): Multiple choice — trophic cascades, keystone species, biodiversity-stability
- Section B (15 pts): Short answer — explain mechanisms using vocabulary (trophic cascade, keystone species, functional redundancy)
- Section C (15 pts): Data analysis — interpret graphs of sea surface temperature and coral cover % from 1980–2020
- Section D (15 pts): CER argument — argue for/against climate as primary cause of coral decline in a marine protected area
Open the Part 2 Form
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Part 2 — Cumulative Assessment (continued)
Continuation of Part 2 assessment — use the same form link.
Climate Data Reference — Coral Reef Case Study
Use this reference context while working through Part 2 Sections C and D. The Great Barrier Reef is the world's largest coral ecosystem (344,000 km²) and a UNESCO World Heritage Site. It is also a Marine Protected Area — yet it experienced mass bleaching events in 2016, 2017, 2020, 2022, and 2024.
Key Data Points to Know
- The bleaching threshold for most coral species is when ocean temperatures exceed the summer maximum by +1°C for 4+ consecutive weeks
- Global ocean surface temperature has risen ~0.9°C since 1850, with acceleration after 1980
- The 2016 bleaching event killed 50% of shallow-water corals in the northern Great Barrier Reef
- Reefs in MPAs with no local pollution bleached at the same rate as reefs adjacent to urban areas — pointing to global rather than local cause
- Coral can recover from bleaching in 10–15 years IF temperatures do not spike again — but the interval between bleaching events is shrinking
Part 3 — Misconception Check
Identify and correct common misconceptions about ecosystem dynamics and climate change.
Part 3 — Misconception Check (20 pts | ~20 min)
Scientists learn as much from identifying wrong thinking as from confirming right thinking. This part presents common student misconceptions about ecosystems and climate change. For each, explain why the misconception is wrong and what the scientifically accurate understanding is.
Misconceptions You May Encounter
- "Ecosystems are stable and don't change." → Ecosystems are dynamic; populations fluctuate and respond to changes (CCC-7: Stability and Change)
- "Food chains are simple and linear." → Food webs are complex networks; removing one species affects many others through trophic cascades
- "Biodiversity is 'nice to have' but not essential." → Biodiversity provides stability, functional redundancy, and essential ecosystem services
- "Protected areas are safe from climate change." → Global atmospheric and ocean temperature changes penetrate all protected areas; local protection does not stop global warming
Open the Part 3 Form
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Part 3 — Misconception Check
Targeted check of the most common misconceptions from this cycle. (20 points, ~20 min)
Standards Self-Assessment (8 pts — completion credit)
Rate your confidence on each Cycle 8 standard. This is completion credit — there are no wrong answers. Honest self-reflection helps your teacher plan reteach sessions.
- MS-LS2-4: I can construct an argument that changes to an ecosystem affect populations (trophic cascades)
- MS-LS2-2: I can predict interaction patterns across ecosystems when a keystone species is removed
- MS-LS2-5: I can evaluate competing design solutions for maintaining biodiversity
- CCC-7: I can apply Stability and Change to explain ecosystem dynamics
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Enrichment & Extension
Go Deeper
Optional content if you finish early or want to go deeper.
Scientist Spotlight: Sylvia Earle
Sylvia Earle (b. 1935) is a marine biologist, oceanographer, and explorer who has spent more than 7,000 hours underwater — more than almost any other human in history. She was the first woman to serve as Chief Scientist of NOAA (the U.S. ocean and atmosphere agency), and National Geographic named her "Hero for the Planet." Earle has documented firsthand the decline of coral reefs she first dove in the 1950s — reefs that were vibrant and diverse then are now bleached wastelands in many places. She coined the term Hope Spots for marine protected areas that need urgent protection, and has campaigned tirelessly for expanding ocean MPAs. Her most urgent message is also the most hopeful: the ocean has recovered everywhere humans have given it a chance. If we reduce CO₂ emissions and expand protections now, she says, the sea's resilience can still reassert itself. You are studying the science that makes her argument possible.
Environmental Justice: North St. Louis Urban Heat Island
St. Louis is one of the most heat-vulnerable cities in the United States. A 2021 study found that predominantly Black neighborhoods in North St. Louis — including Walnut Park, Baden, and Penrose — are 5–12°F hotter than predominantly white neighborhoods in the same city during summer heat waves. This is the urban heat island effect: decades of disinvestment left North St. Louis with fewer trees, more pavement, and less green space than wealthier areas. The consequences are life-and-death: heat is the leading weather-related killer in the U.S., and North St. Louis residents face far higher heat mortality risk. Climate change is making every heat wave hotter and longer. But the communities hit hardest contributed the least to the greenhouse gas emissions causing it. St. Louis researchers are now studying how restoring urban tree canopy and green infrastructure in North City could reduce local temperatures by 3–5°F — demonstrating that climate adaptation is also an environmental justice imperative.
Week 3 Complete!
Next Week: Year-End Integration — synthesize everything you've learned across all 8 cycles!