Science Fenns K-5Grades K to 5
A town beside a river with a restored wetland, a park, and a stormwater ditch next to a dumping pile.

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People and Ecosystems

How human activity helps and harms.

Lesson 38 of 41

Try this first

Before we start

Today’s story

People and Ecosystems

People live in ecosystems too. We build towns, grow food and use water. What we do changes the living and nonliving parts around us.

Some actions harm. Pollution can kill fish. Draining wetlands removes homes for birds and frogs. Cutting a forest can wash soil into rivers. Too many invasive plants can crowd out native ones.

Some actions help. People plant trees, clean creeks and restore wetlands. They build wildlife crossings and protect land. We can choose. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Test the Runoff

    25 minutes · Do this with a grown-up nearby

    You need

    • two baking pans
    • soil
    • grass clumps or sod
    • a watering can
    • water
    • a ruler to prop pans
    • clear cups

    Do this

    1. Fill one pan with bare soil and one with soil and grass.
    2. Prop both pans at the same slope.
    3. Set a cup at the low end of each.
    4. Pour the same amount of water on each.
    5. Look at the water in the cups.
    6. Compare the cloudiness.
    Write or draw: A sketch of each pan and the cups. Write which water is clearer and why.

    Watch for: Bare soil sends muddy water downhill. Grass holds soil in place. This shows why plants matter to rivers.

    Safety: Work over a tray or outside and wipe up spills.

    Same every time

    Three rules

    Rule 1Every action has an effect.

    Some are small and some are large.

    Rule 2Habitat loss is a big harm.

    Animals need a place to live.

    Rule 3People can repair.

    Planting and cleaning bring life back.

    Grandpa Fenn’s notebook

    Say it like a scientist

    habitat loss
    When a place where animals live is destroyed or changed.
    invasive
    A species that moves in and harms native life.
    restoration
    Bringing a damaged place back to health.
    runoff
    Water that flows over land into streams.

    Poppy’s quiz

    Six questions

    Tap an answer. Green means right. You will see why.

    Talk about it

    Say it out loud

    • What evidence can show a change in an ecosystem was harmful or helpful?
    • What could your town do to help a nearby creek or park?
    Did you know

    Wetlands soak up floodwater like sponges, which is one reason towns work to restore them.

    Someone who does this

    A conservation biologist works to protect and restore wild places.

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