3rd Grade Science

Investigating ecosystems, matter, and energy through hands-on experiments and observations.
Basic Concepts

Exploring Ecosystems

What is an Ecosystem?

An ecosystem is a community of living things—like plants, animals, and tiny microbes—interacting with each other and with their environment. Ecosystems can be as big as a forest or as small as a puddle!

Living and Nonliving Parts

  • Living parts: Plants, animals, fungi, and bacteria.
  • Nonliving parts: Sunlight, water, rocks, soil, and air.

All of these work together to create a balanced system where each part depends on the others.

Observing Ecosystems

You can observe ecosystems right in your own backyard or local park. Watch how ants build their homes, or see how birds use trees for shelter.

Why Ecosystems Matter

Ecosystems provide us with food, clean air, and water. They help control the climate and even decompose waste!

Try This!

  • Take a walk and list all the living and nonliving things you see.
  • Make a mini-ecosystem in a jar using soil, a small plant, and a little water.

Examples

  • A pond is home to fish, frogs, plants, and insects, all interacting together.

  • A fallen log in the forest provides shelter for bugs, fungi, and small animals.

In a Nutshell

Ecosystems are communities where living and nonliving things interact and depend on each other.

Key Terms

Ecosystem
A community of living and nonliving things that work together.
Habitat
The natural home of a plant or animal.
Organism
A living thing, like a plant, animal, or microbe.