6th grade Reading rock layers and the history of life worksheet

Reading rock layers and the history of life

Grade 6 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Use this

   Two rock columns, not to scale.

3. 1.

   Two sites far apart both have a shale layer with the same index trilobite. Which layer at Site 2 matches the trilobite shale at Site 1, by Esme's matching?

   • The coal on top, since it is the youngest layer there
   • The conglomerate at the bottom
   • Whichever layer is thickest
   • The shale with the same trilobite
4. 2.

   At Site 1, limestone lies above the trilobite shale. At Site 2, coal lies above the same shale. What can Jun say about the limestone and the coal?

   Use the picture in question 1.

   • The coal is older than the shale
   • They must be exactly the same age
   • Both are younger than the trilobite shale
   • Both are older than the shale, since they are higher up
5. 3.

   Why is a short-lived, widespread fossil so useful for matching layers at sites far apart, as Kira explains?

   • It shows which layer is on top at each of the two sites
   • Rocks holding it formed in the same short span
   • It lived a long time, so it turns up in many layers
   • It shows the two sites were once touching
6. 4.

   Luz's friend says early people and dinosaurs lived at the same time. Which response is best?

   • Disagree: those dinosaurs were extinct about 66 million years before people
   • Agree: their fossils are in the same layers
   • Agree: cartoons and movies often show them living together
   • Disagree: dinosaurs lived after people
7. 5.

   Noah's cousin says any fossil can tell the exact age of a rock. Which response is best?

   • Disagree: index fossils narrow the age; radioactive dating gives numbers
   • Disagree: fossils show nothing about age
   • Agree: bigger fossils are older, so their size tells the age
   • Agree: each fossil shows its own year
8. 6.

   Cross-section, not to scale. Layers A (bottom), B and C are cut by a dike. Layer D lies on top and is not cut. Which order of events, oldest first, does Pia choose?

   • Layer D, then C, B, A, then the dike
   • Layers A, B, C, then the dike, then D
   • The dike first, then layers A, B and C, then layer D
   • Layers A, B, C, D, then the dike
9. 7.

   A fault cuts layers A to C. Layer B holds an index fossil from about 300 million years ago. What can Ren say about the fault?

   • It formed this century
   • It is older than 300 million years, since it cuts deep
   • It is exactly 300 million years old
   • It is younger than about 300 million years
10. 8.

    The bottom layer has ichthyosaurs (sea reptiles) and ammonites, the middle layer has ammonites but no ichthyosaurs, and the top layer has neither. Which story fits, by Tala's reading?

    • Ammonites became extinct first; ichthyosaurs lasted much longer
    • Ichthyosaurs became extinct first; ammonites lasted longer
    • Both groups still live in those seas
    • The three layers formed in one year

11. A 24-hour clock face for Earth's history

    Midnight at the start is Earth forming; the next midnight is today.

12. 9.

    Squeeze Earth's 4.5 billion years into one 24-hour day. When does Zee find that dinosaurs (other than birds) became extinct?

    • At about 11:39 p.m.
    • At about noon
    • At about 6 p.m.
    • Seconds before midnight, alongside the first people
13. 10.

    On the same 24-hour day, when do modern people appear, about 300,000 years ago? Ari works it out.

    • At about 11:39 p.m., with the dinosaurs
    • About 6 seconds before midnight
    • In the very first hour, just as the Earth formed
    • At about noon, halfway through