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9th grade · Science · Unit 14 of 14

Ecosystem Stability

Relationships among organisms, succession, and how ecosystems recover from disturbance.

What your child practices

Your child explains how the relationships in an ecosystem and ecological succession make it resilient and help it recover after a disturbance.

Alabama Course of Study content standard: BIO.6; BIO.10 · interactions among organisms in an ecosystem, and succession and recovery from disturbance

How we explain it

Children can open this short lesson before they practice.

  1. Relationships and biodiversity make ecosystems resilient.
  2. After a disturbance, succession brings back grasses, then shrubs, then trees.
  3. Producers are the first trophic level. Restoring wetlands gives habitat and buffers storms.

Example: After a storm, grasses and shrubs return first, then young pines. What is this? The soil was still there. Regrowth on existing soil is secondary succession. Answer: secondary succession

Ecosystem Stability in Alabama

In the Alabama Course of Study, this is unit 14 of 14 in 9th grade Science, after Populations & Stability.

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: Alabama State Department of Education (ALSDE)

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 ecosystem with many species usually recovers from a disturbance…

    • worse than one with few species
    • never
    • better than one with few species
    • only if all predators are removed

  2. Question 2

    A longleaf pine forest that burns lightly every few years and quickly regrows shows…

    • extinction
    • primary succession
    • resilience
    • an invasive species

  3. Question 3

    Why are there fewer top predators than herbivores?

    • Less energy reaches higher levels
    • Predators live longer
    • Herbivores are smaller
    • Predators eat less

  4. Question 4

    A tick feeding on a white-tailed deer is an example of…

    • parasitism
    • commensalism
    • mutualism
    • competition

  5. Question 5

    Removing a top predator such as wolves can cause deer to…

    • overgraze plants, lowering biodiversity
    • disappear at once
    • become producers
    • eat less

  6. Question 6

    A stable ecosystem…

    • never changes at all
    • returns to similar conditions after small disturbances
    • has only one species
    • cannot recover

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