• 1. Get ready.
    Cut 20 small slips of paper and write the names of the following animals in the Shark Bay food web: 4 bottlenose dolphins, 7 dugongs, 7 green sea turtles, and 2 tiger sharks.

    2. Get set.
    Spread the slips out on a desk or table.

    3. Play!

    • Designate one section of the table as an area of sea grass. The sea grass supports many animals and is very important to the ecosystem.
    • Put all the dugong and turtle slips in the sea grass area. Sea grass is their favorite type of food!
    • Put the dolphin slips near the sea grass. They might be looking for fish to eat.
    • Move the tiger sharks slips toward the dolphins, turtles, and dugongs. The sharks are hungry—what will they decide to eat today? Each shark “eats” one of the other animals. Remove the slips of the two “eaten” animals.
    • Dolphins are becoming alarmed at the number of sharks swimming around. Move the dolphin slips to another area away from the sea grass to keep clear of the sharks.
    • Finally, each shark returns to the sea grass and “eats” another turtle or dugong. Remove two more slips.

    Quiz Yourself!

    1. Why are tiger sharks important in Australia's Shark Bay ecosystem?

      The tiger sharks keep the dolphins from eating too many fish. They keep the sea turtles and dugongs from eating too much sea grass.

  • Materials You Provide

    • Paper
    • Pencils
    • Pens
    • Scissors

    Recommended Prior Activities

  • Background Information

    An ecosystem is home to interconnected species that form food webs. A keystone species is a species that has a major influence on the structure of an ecosystem. Its presence affects many other members of the ecosystem. A simulation of a Shark Bay food web shows how species are connected. It also shows what might happen if a keystone species disappears.


    Term Part of Speech Definition Encyclopedic Entry
    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    food web Noun

    all related food chains in an ecosystem. Also called a food cycle.

    Encyclopedic Entry: food web
    keystone species Noun

    a species that has a major influence on the way an ecosystem works.

    Encyclopedic Entry: keystone species
    species Noun

    group of similar organisms that can reproduce with each other.


National Science Foundation