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8th grade · Science · Unit 13 of 13

Food Web Disruptions & Biodiversity

How disruptions ripple through food webs, and why variety keeps ecosystems stable.

What your child practices

Practices how population changes, natural disasters and human actions disrupt the flow of energy in food webs, and how biodiversity makes an ecosystem more stable and its organisms healthier, with Texas examples such as Gulf Coast marshes, invasive species and coastal prairie.

Texas Essential Knowledge and Skills (TEKS) teks student expectation: 8.12(A); 8.12(C) · how disruptions affect energy transfer in food webs, and how biodiversity supports stable, sustainable ecosystems

How we explain it

Children can open this short lesson before they practice.

  1. Population changes, disasters and human actions can break links in a food web.
  2. More biodiversity makes an ecosystem more stable: predators can switch to other prey.
  3. Ecosystem services are benefits people get from ecosystems, like clean water.

Example: Why can a predator survive in a diverse ecosystem when one prey species declines? Diverse ecosystems have many kinds of prey. The predator eats something else. Answer: it can switch to other prey

Food Web Disruptions & Biodiversity in Texas

In the Texas Essential Knowledge and Skills (TEKS), this is unit 13 of 13 in 8th grade Science, after What Changes Climate.

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: Texas Education Agency (TEA)

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

    Why do fewer salmon harm orcas?

    • Salmon hunt orcas
    • Orcas like empty water
    • Orcas have less food
    • Orcas eat only plants

  2. Question 2

    Attwater's prairie chickens nearly disappeared when most Texas coastal prairie was plowed or built on. This shows that…

    • habitat does not matter
    • losing habitat can push a species toward extinction
    • prairie chickens live in cities
    • plowing adds habitat

  3. Question 3

    Ecosystem services are…

    • benefits people get from ecosystems
    • cleaning services
    • car repairs
    • jobs at a zoo

  4. Question 4

    Ecosystems with high biodiversity are usually…

    • more stable
    • less stable
    • always deserts
    • lifeless

  5. Question 5

    If a disease wiped out most rabbits in an area, coyotes and hawks would…

    • have less food and might decline
    • switch to eating grass
    • have more food
    • not change at all

  6. Question 6

    Zebra mussels spread into some Texas lakes and filter out huge amounts of plankton. Native fish that eat plankton…

    • are not affected
    • have more food
    • have less food
    • turn into mussels

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