Reading rock layers and the history of life

Grade 6 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   not to scale

3. 1.

   Ari sketches a cliff with four flat, undisturbed rock layers, A on top down to D at the bottom. Which layer is the oldest?

   • B, since it is the thickest
   • D, at the bottom
   • A, at the top
   • Each layer is the same age
4. 2.

   Looking at the same cliff, Bo wants the youngest layer. Which layer is it?

   Use the picture in question 1.

   • C, in the middle
   • A, at the top
   • The one with the most fossils
   • D, at the bottom
5. 3.

   Layer B with fish-shaped fossils above layer C with shell-shaped fossils; the layers are flat. Layer B has fish fossils, and layer C just below it has shell fossils. The layers are flat and undisturbed. Which fossils does Kira say are older?

   • The fish in layer B
   • The shells in layer C
   • Whichever fossil is bigger
   • Both are the same age
6. 4.

   On a mountain hike, Jun finds fossil seashells in rock far above the sea. What does that show?

   • Birds dropped the shells there recently
   • Sea animals once climbed the mountain
   • The rock formed under the sea long ago
   • The shells grew after the mountain formed last century
7. 5.

   Low layers hold fossils of sea creatures unlike any living today; high layers hold fossils like today's clams. What does Milo conclude?

   • Life on Earth has changed over time
   • The upper fossils are the older ones
   • Today's clams were the first life
   • The kinds of life stayed the same
8. 6.

   Noah is making a time-line poster. Which list puts the three eras in order, oldest first?

   • Cenozoic, Mesozoic, Paleozoic
   • Paleozoic, Cenozoic, Mesozoic
   • Mesozoic, Paleozoic, Cenozoic
   • Paleozoic, Mesozoic, Cenozoic
9. 7.

   Three picture cards (trilobite, dinosaur, early person) next to a blank time line from older to today. Ren puts three fossil cards on the time line: trilobites, dinosaurs and early people. Which order is right, oldest first?

   • Dinosaurs, then people, then trilobites
   • Trilobites, then people, then dinosaurs
   • People and dinosaurs together, then trilobites
   • Trilobites, then dinosaurs, then people
10. 8.

    A blank time line from Earth's start to today. About how old is the Earth, according to the USGS page Tala is reading?

    • About 45,000 years
    • About 100 billion years
    • About 4.5 billion years
    • About 4.5 million years
11. 9.

    How did scientists work out Earth's age, as Zee reads on the USGS page?

    • By judging how old the oldest fossils look
    • By guessing from how tall mountains are
    • By counting the layers in one cliff
    • By measuring radioactive elements in old rocks and meteorites
12. 10.

    A long time line from Earth's start to today, with a blank box at the right end. Esme compares how long people have been around with Earth's whole history. Which fits?

    • A tiny sliver at the very end
    • About half of Earth's history
    • Almost the whole of Earth's history
    • Ever since Earth formed