10.1 · What an Ecosystem Is

From Ohio 5th Grade Science Power Workbook · Chapter 10 · Lesson 10.1.

Big idea: An ecosystem is all the living and non-living things in one place. It also includes the ways they affect each other.

Learning goals: Describe what an ecosystem includes

Tell living parts from non-living parts

Give examples of Ohio ecosystems

Living and non-living together

An ecosystem is everything in one place. It includes the living things and the non-living things. It also includes the way they affect each other.

The living parts are the plants, animals and other organisms. The non-living parts include water, soil, air and sunlight.

Ohio has many of them

A pond, a woodland, a wetland, a stream, a meadow and even a city park are all ecosystems.

They can be tiny or enormous. What makes something an ecosystem is not its size but that the parts affect each other.

Worked examples

Question: A student lists what is in a woodland: oak trees, squirrels, earthworms, soil and rainfall. Which are living and which are non-living, and why do both belong in the list?

Steps: Sort them. Oak trees, squirrels and earthworms are living. Soil and rainfall are non-living.

Ask whether the non-living parts matter. The trees need the soil and the water to grow.

Because the living things depend on the non-living ones, both belong in a description of the ecosystem.

Answer: Living: oak trees, squirrels, earthworms. Non-living: soil, rainfall. Both belong because the living things depend on the non-living ones.

Common mistakes

An ecosystem is not just the animals

When people picture an ecosystem they picture the creatures in it and forget everything else.

Water, soil, air and sunlight are as much part of the ecosystem as the fish and the foxes — and when one of them changes, the living things change too.

Check your thinking: List the non-living parts on purpose. If your description has only creatures in it, it is not finished.

Ohio connection

Lake Erie is one enormous ecosystem

Lake Erie holds algae, insects, small fish such as minnows, and larger fish that eat them. It also holds the water itself, the sunlight reaching the surface and the sediment on the bottom.

Change one part and the others feel it. Ohio scientists watch the lake closely for exactly that reason.

Think: Sunlight only reaches the top part of a deep lake. Why would that matter to the algae, and then to the fish?

Remember

Alive, not alive, and connected

Three things make an ecosystem: the things that are alive, the things that are not alive, and the connections between them.

Practice tip

Remember: Non-living parts are part of the answer.

Tip: When Ohio asks you to describe or compare ecosystems, include water, soil, air and sunlight. Many questions turn on one of those changing.

Written practice

Describe an Ohio pond as an ecosystem. Name two living parts and two non-living parts, and explain one way a non-living part affects a living one.

Sample response: Living parts of an Ohio pond include algae and fish. Non-living parts include the water and the sunlight. The sunlight matters to the algae because algae use the sun's energy to make their own food, and if the algae had no sunlight the fish that eat them would have less food too.

Scoring guide: 1 point: names two living parts and two non-living parts correctly.

1 point: explains a real connection, such as sunlight letting the algae make food, or water being needed by everything in the pond.

Ohio assesses the roles and relationships of organisms within an ecosystem, which means the connections, not just a list.