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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.

Alaska content standards 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 Alaska

In the Alaska content standards, 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: Alaska Department of Education and Early Development

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

    Variation within a species means…

    • individuals have different traits
    • no individuals reproduce
    • all individuals are identical

  2. Question 2

    A cactus's thick stem that stores water is an adaptation to…

    • ocean tides
    • cold lakes
    • dry climates

  3. Question 3

    Artificial selection occurs when…

    • wind chooses seeds
    • humans choose which organisms reproduce
    • predators choose prey

  4. Question 4

    Roughly how old is Earth?

    • about 4.5 billion years
    • about 4.5 million years
    • about 4500 years

  5. Question 5

    Bacteria can become resistant to antibiotics when…

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

  6. Question 6

    Sexual selection is when…

    • animals avoid all mates
    • traits that help with digestion are lost
    • traits that help attract mates become more common

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