Impact Extinction Worksheet
High School Earth Science • Earth History
The Day the Sky Fell: Asteroid Impact & Mass Extinction
K-Pg Event Study
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Key Scientific Terms (Visual Glossary)
Asteroid Impact
A massive space rock striking Earth at extreme speed, releasing immense kinetic energy and heat.
Mass Extinction
A rapid planetary event where a high percentage (75%+) of all living species die out completely.
Impact Winter
A freezing, dark global climate caused by airborne soot and sulfur blocking sunlight for months or years.
Food Web Collapse
When plant producers die without light, herbivores starve, causing predators to starve in turn.
Guided Reading: The Chicxulub Catastrophe
1 The Cosmic Collision (66 Million Years Ago)
Around 66 million years ago, a 6-mile-wide asteroid (about the size of Mount Everest) crashed into Earth's crust near Chicxulub, Mexico. The collision released energy equal to billions of atomic bombs. The explosion instantly produced catastrophic shockwaves, towering mega-tsunamis, and continent-wide wildfires that burned vast prehistoric forests.
2 Global Darkness and the "Impact Winter"
The true killer was not just the impact blast, but the atmospheric aftermath. The collision vaporized underground sulfur and rock, throwing billions of tons of soot and dust into the upper atmosphere. Jet streams carried this cloud blanket around the world, completely blocking out the sun. In this dark, freezing impact winter, global temperatures plummeted, and the vital biological process of photosynthesis ground to a halt.
3 Food Web Collapse & The Geological Record
Without sunlight, plants and marine plankton withered. Large plant-eating dinosaurs like Triceratops starved within months. Without prey, apex predators like Tyrannosaurus rex perished, causing a complete food web collapse. Approximately 75% of all species vanished in this mass extinction. Only small, generalist scavengers like early burrowing mammals and avian ancestors survived.
Geological Evidence: Rock layers worldwide contain a distinct boundary clay layer enriched with iridium—a metallic element very rare on Earth's surface but exceptionally concentrated in asteroids.
Earth Science Module: Chicxulub & The K-Pg Mass Extinction Page 1 of 2 • Continue to Page 2 for Comprehension Tasks
Check Your Understanding: Impact & Extinction
Page 2 Assessment
A Cause & Effect: The Chain of Extinction
Fill each box using the word bank below
Word Bank: Photosynthesis Soot & Dust Herbivores Mass Extinction
1. Impact Blast
Asteroid ejects huge clouds of:
2. Dark Sky
No light stops plants from:
3. Web Breaks
Plants die, starving plant-eating:
4. Result
Predators starve, resulting in a:
B Multiple Choice (Circle the letter of the correct answer)
1. What was the direct environmental cause of plant death worldwide after the impact?
A Direct impact shockwave knocked over every tree
B Thick soot and dust clouds blocked sunlight needed for life
C The entire global ocean evaporated into thin air
D Toxic space bacteria infected all plant leaves
2. How do geologists confirm an extraterrestrial asteroid caused this extinction?
A All dinosaur fossils have distinct meteor burn marks
B Ancient cave paintings depict the fiery asteroid
C A worldwide rock layer contains high levels of the element iridium
D Deep ocean trenches opened up and swallowed the dinosaurs
C Scientific Explanation (Sentence Starters)
Complete both statements
Question: Even though Tyrannosaurus rex was thousands of miles away from the initial collision blast, why did it still starve to death?
Include key terms: producers / sunlight herbivores / prey food chain
Step 1 (Sunlight & Plants):
Large meat-eating dinosaurs like T. rex could not survive because when soot blocked the sun,
Step 2 (Food Chain & Carnivores):
Because plant-eating herbivores died out, top predators had no food left, which caused them to
Self-Check: Did you write clearly and check your vocabulary words? Page 2 of 2 • Completed
Impact Extinction Answer Key
Teacher Answer Key & Instructional Guide
The Day the Sky Fell: Impact & Extinction
Grading & Support Guide
NGSS: HS-ESS1-4 • HS-LS2-6
Core Science Objectives
Students analyze how an astronomical event (asteroid collision) disrupted Earth's atmosphere, triggering an impact winter, halting photosynthesis, and initiating a bottom-up food web collapse that resulted in the K-Pg mass extinction.
Neurodiversity & Executive Function Supports (Sophomore Level)
Predictable Chunking
Each paragraph is limited to one core scientific idea with a visual icon badge. Encourage the student to highlight or track one paragraph at a time using a ruler or index card.
Reduced Motor Demand
The worksheet uses multiple choice, closed word-bank fills, and pre-written sentence starters to reduce handwriting fatigue while keeping high conceptual rigor.
Explicit Cause-and-Effect
Autistic students often excel with linear, logic-based models. The 4-step sequence organizer on Page 2 makes the causal chain concrete and unambiguous.
Sensory & Processing Time
If the student experiences sensory or cognitive fatigue, allow them to complete Page 1 reading and Task A during class, and Tasks B & C during guided study or as a follow-up.
Target Vocabulary & Common Student Misconceptions
Misconception: "The asteroid landed on all the dinosaurs." Clarification
Scientific Fact: The asteroid struck only one spot (Yucatán Peninsula). The catastrophic driver was global climate change and darkness caused by atmospheric soot, which caused global famine over months and years.
Misconception: "Every single animal on Earth died." Clarification
Scientific Fact: ~75% of species died, especially large animals with massive caloric needs. Small burrowing mammals, scavengers, turtles, crocodiles, and small avian dinosaurs (modern birds' ancestors) survived.
Term Note: Iridium (Chemical Element #77) Geology Evidence
During Earth's differentiation, heavy iridium sank to the planet's core. Surface rock layers with 30-100x normal iridium levels (the "Alvarez Hypothesis") proved a space body collision occurred.
Teacher Guide: Chicxulub & Extinction • High School Science Page 1 of 2 • Flip for Solutions & Sample Responses
Answer Key & Scoring Criteria (Page 2 Tasks)
Grading Key
A Cause & Effect Sequence Chain Solutions (4 Points Total)
1 pt per correct slot
