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9th grade · Science · Unit 8 of 10

Evolution & Selection

Variation, adaptation and how populations change over time.

What your child practices

Practices variation, adaptation, natural and artificial selection, mutations, the evidence for evolution from fossils and rock layers, and how new species can form.

Maine Learning Results learning standard: HS-LS4-2; HS-LS4-4 · natural selection and adaptation in populations

How we explain it

Children can open this short lesson before they practice.

  1. Variation and mutations give individuals different traits. Adaptations help them survive where they live.
  2. Natural selection lets well-suited individuals reproduce more; in artificial selection, people choose.
  3. Fossils and rock layers show life changed over time, starting with single-celled organisms.

Example: A cactus stores water in its thick stem. This is an adaptation to what? Storing water helps when rain is rare. Answer: dry climates

Evolution & Selection in Maine

In the Maine Learning Results, this is unit 8 of 10 in 9th grade Science, after Chemical Change and before Energy & Magnetism.

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

    Bacteria can become resistant to antibiotics when…

    • the drug creates new bacteria
    • some bacteria survive the drug and multiply
    • all bacteria change on purpose

  2. Question 2

    Older fossils are usually found in…

    • higher layers
    • water only
    • deeper rock layers

  3. Question 3

    Which of these must be true for natural selection to occur?

    • traits cannot be passed on
    • every organism is the same
    • traits vary and can be inherited

  4. Question 4

    A new species can form when…

    • one animal changes in a day
    • two species are identical
    • populations become separated and adaptations build up over time

  5. Question 5

    Which is an example of artificial selection?

    • fish living in a cave
    • a bird growing a longer beak by exercise
    • farmers breeding cows that give more milk

  6. Question 6

    Why do scientists compare similar bone structures in different animals?

    • to find evidence of shared ancestors
    • to name the animals
    • to make fossils

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