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8th grade · Science · Unit 8 of 8

Earth's History & Fossils

Rock strata, the geologic time scale and evidence of evolution.

What your child practices

Practices how rock layers are used to build Earth's 4.6-billion-year history, patterns in the fossil record, and anatomical and embryo evidence that living things share ancestors.

Oregon State Standards learning standard: 8.ESS1.4; 8.LS4.1; 8.LS4.2 · rock strata and Earth's history, the fossil record, and anatomical evidence of common ancestry

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Earth is about how old?

    • 100 years
    • 4.6 billion years
    • 6000 years
    • 1 million years

  2. Question 2

    A rock layer cutting across other layers is…

    • the same age
    • impossible
    • older than all of them
    • younger than the layers it cuts

  3. Question 3

    A human arm, bat wing and whale flipper have similar bones. This suggests…

    • they are the same species
    • bones come from food
    • they share a common ancestor
    • it's a coincidence

  4. Question 4

    Homologous structures are…

    • identical in every species
    • made of rock
    • similar body parts from a common ancestor
    • parts with no use

  5. Question 5

    The fossil record shows that…

    • fossils are recent
    • life on Earth has changed over time
    • all species lived at once
    • life has never changed

  6. Question 6

    Ash layers from Cascade eruptions help geologists by…

    • making rocks younger
    • marking the same moment in many places
    • removing fossils
    • creating mountains

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