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8th grade · Science · Unit 6 of 7

Natural Selection

Variation, survival and populations changing over time.

What your child practices

Practices how variation in traits leads some individuals to survive and reproduce more, how populations change over generations, and how artificial selection works.

Maine Learning Results learning standard: MS-LS4-4; MS-LS4-6 · how trait variation affects survival and how populations change over time

How we explain it

Children can open this short lesson before they practice.

  1. Individuals vary. Those with helpful traits survive and reproduce more.
  2. Over generations, helpful traits become more common: natural selection.
  3. In artificial selection, people choose which plants or animals breed, like dog breeds.

Example: Farmers breed only the cows that give the most milk. What is this? People, not nature, are choosing. Choosing by people is artificial selection. Answer: artificial selection

Natural Selection in Maine

In the Maine Learning Results, this is unit 6 of 7 in 8th grade Science, after Genes & Heredity and before Earth's History & Fossils.

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 becoming resistant to antibiotics is an example of…

    • metamorphosis
    • natural selection
    • erosion
    • photosynthesis

  2. Question 2

    Organisms usually produce more offspring than can survive. This leads to…

    • identical offspring
    • no predators
    • competition for resources
    • unlimited food

  3. Question 3

    An adaptation is a trait that…

    • an organism chooses
    • helps an organism survive in its environment
    • harms survival
    • appears overnight

  4. Question 4

    Do individuals evolve during their lifetime?

    • Yes, every day
    • No, populations change over generations
    • Only if they try
    • Only on weekends

  5. Question 5

    Over many generations, helpful traits become…

    • invisible
    • more common
    • extinct always
    • less common

  6. Question 6

    In a cold climate, foxes with thicker fur survive more. Over time the population will have…

    • no change
    • no fur
    • thinner fur on average
    • thicker fur on average

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