Ocean Ecosystems · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The Ocean Is One Big System

Science · Ocean Life · ages 9-11
Name ______________________   Date ____________

  1. An ocean ecosystem includes...

    • Only the living animals and plants
    • Living and non-living together
    • Only the water's temperature and salt

  2. Which of these is a non-living part of an ocean ecosystem?

    • Currents
    • Coral fish
    • Sea turtles

  3. Salinity means how much light reaches the water.

    Circle one:   True   False

  4. Which statement best describes an ocean ecosystem as a system?

    • The living and non-living parts operate separately
    • Only non-living parts affect living things, never the other way
    • The living and non-living parts interact and affect each other

  5. How many non-living factors does this topic name: temperature, salinity, light, and currents? Type the number.

    Answer: ______________

  6. A current shifts and brings colder water to a reef. What is the best way to think about what happens next?

    • It could affect plankton, then fish, then bigger animals
    • Only the water temperature changes, nothing else
    • The change stays in the water and never reaches living things

  7. A big storm stirs up the ocean and changes the currents in one area for a week. Which is the most likely result?

    • Nothing changes because ecosystems are separate from currents
    • Only the color of the water changes forever
    • Changed currents could move nutrients and fish food

  8. Jake says, 'A drop in ocean temperature only matters to fish that live in cold water.' What is wrong with Jake's thinking?

    • Nothing, Jake is right
    • He forgot it can move through the whole food web
    • He forgot that temperature never changes in the ocean
LightMySky · lightmysky.comW1-mt_w4OYcWJs6H-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

The Ocean Is One Big System W1-mt_w4OYcWJs6H-s1

  1. Living and non-living together · An ecosystem is the whole system: living things and non-living factors interacting together.
  2. Currents · Currents are moving water, not living things. Fish and turtles are living parts of the ecosystem.
  3. False · Salinity means how much salt is dissolved in the water. Light is a separate, different factor.
  4. The living and non-living parts interact and affect each other · In a system, living and non-living parts interact. Living things can even affect non-living conditions, like how plankton affect how clear the water is.
  5. 4 · Temperature, salinity, light, and currents: that's four factors.
  6. It could affect plankton, then fish, then bigger animals · In a real ecosystem, a change in one factor tends to move through the whole food web.
  7. Changed currents could move nutrients and fish food · Currents carry nutrients and heat. When they shift, the animals that depend on those conditions feel the effects too.
  8. He forgot it can move through the whole food web · A change in temperature can shift plankton growth, which then affects many animals up the food web, not just cold-water fish.
Worksheet · LightMySky