The K-Pg Extinction: How the Dinosaurs' Reign Ended

Science · Dinosaurs & Paleontology · ages 9-11

Name ______________________ Date ____________

Which group of dinosaurs died out completely in the K-Pg extinction?
- Every single dinosaur, including birds
- Non-avian dinosaurs (the ones that were not birds)
- Only small dinosaurs
A museum label says a dinosaur fossil is about 66 million years old. When did this dinosaur die?
- Around the same time as the K-Pg extinction
- Long before the K-Pg extinction
- Long after the K-Pg extinction
Most scientists think a giant asteroid hitting Earth was a major cause of the dinosaur extinction.
Circle one: True False
Geologists around the world find a thin rock layer from 66 million years ago that is unusually rich in one metal. Which metal?
- Iridium
- Iron
- Gold
What is the name of the crater linked to the asteroid that struck Earth 66 million years ago?
- Yucatan crater
- Meteor crater
- Chicxulub crater
Why does a worldwide iridium layer support the asteroid impact idea?
- Iridium only forms inside dinosaur bones
- Iridium is rare on Earth but common in space rocks like asteroids
- Iridium only comes from volcanoes
Right after the asteroid struck Earth, which of these happened first?
- The impact carved out a giant crater
- Dust blocked out the sunlight for years
- Plants died from lack of light
A friend says, "The asteroid killed every dinosaur in one instant." What is wrong with this idea?
- Nothing is wrong, the asteroid worked instantly
- The asteroid only affected the ocean, not land
- The impact set off dust clouds and cold that killed plants and animals over months and years

Answer key

For grown-ups. Fold this page away before handing over the rest.

Non-avian dinosaurs (the ones that were not birds) · Non-avian dinosaurs died out. Birds are dinosaurs too, and they survived.
Around the same time as the K-Pg extinction · The K-Pg extinction happened about 66 million years ago, the same age as the fossil, so this dinosaur died around that time.
True · Evidence like the Chicxulub crater and the iridium layer support the asteroid impact idea.
Iridium · The worldwide iridium layer is a key clue linking the extinction to an asteroid impact.
Chicxulub crater · The impact left the Chicxulub crater, located on Mexico's Yucatan Peninsula.
Iridium is rare on Earth but common in space rocks like asteroids · Because iridium is scarce on Earth's surface, a sudden worldwide layer of it points to material falling from space.
The impact carved out a giant crater · The crater formed the instant the asteroid hit. The dust, darkness, and dying plants followed after.
The impact set off dust clouds and cold that killed plants and animals over months and years · The asteroid's dust blocked sunlight, and the extinction unfolded over time as plants and food chains collapsed.