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8th grade · Science · Unit 7 of 7

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.

Maine Learning Results learning standard: MS-ESS1-4; MS-LS4-1; MS-LS4-2 · rock strata and Earth's history, the fossil record, and anatomical evidence of common ancestry

How we explain it

Children can open this short lesson before they practice.

  1. Rock layers and fossils order Earth’s 4.6-billion-year history; lower layers are older.
  2. Most of that history is the Precambrian. We live in the Cenozoic Era.
  3. Homologous structures show that living things share ancestors.

Example: In which era do we live today? The eras go Paleozoic, Mesozoic, Cenozoic. The latest is the Cenozoic. Answer: the Cenozoic Era

Earth's History & Fossils in Maine

In the Maine Learning Results, this is unit 7 of 7 in 8th grade Science, after Natural Selection.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Maine Department of Education

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

    An index fossil is useful because it…

    • is very rare
    • lived for a short time over a wide area
    • lived everywhere forever
    • has no age

  2. Question 2

    The geologic time scale divides Earth's history by…

    • calendar years
    • seasons
    • major events in the rock and fossil record
    • presidents

  3. Question 3

    We live in the…

    • Mesozoic Era
    • Paleozoic Era
    • Precambrian
    • Cenozoic Era

  4. Question 4

    Which era is called the Age of Dinosaurs?

    • Mesozoic
    • Precambrian
    • Cenozoic
    • Paleozoic

  5. Question 5

    Most of Earth's history took place in the…

    • Cenozoic
    • Mesozoic
    • Jurassic
    • Precambrian

  6. Question 6

    Vestigial structures, like the human tailbone, are…

    • new organs
    • parts from food
    • reduced parts that once had a use in ancestors
    • always harmful

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