Explore Habitats and Ecosystems

Every living thing depends on the place around it. An ecosystem includes living organisms and the nonliving parts of their environment, along with the interactions among them. This lesson introduces habitats and ecosystems so you can begin to see how plants, animals, water, soil, and weather are connected.

What is a habitat?

A habitat is a place where an organism lives. A pond can be a habitat for fish, frogs, insects, and plants. A tree can provide a habitat for birds, insects, fungi, and other organisms. A habitat provides things organisms need, such as food, water, shelter, and space. Different organisms may use the same place in different ways.

Habitats can be large or small

A forest is a large habitat with many smaller places inside it: under leaves, in tree branches, beside a stream, or in the soil. A fallen log can be a small habitat for insects and fungi. The size depends on what organism you are studying and what resources it needs.

Organisms include plants, animals, fungi, and microscopic life. A habitat is not only a background. The organisms interact with the place and with one another. A bird may use a tree for shelter, while the tree needs light, water, air, and nutrients to grow.

Living and nonliving parts

Biotic means living or once living, and abiotic means nonliving. Plants, animals, fungi, and fallen leaves are biotic parts. Sunlight, water, air, temperature, rocks, and soil minerals are abiotic parts. Dead leaves are no longer alive, but they came from a living thing and can be used by decomposers.

Imagine a school garden. It may include seedlings, worms, birds, and insects, as well as soil, water, air, and sunlight. If a plant grows poorly, several factors could matter: the amount of light, water, space, soil conditions, or damage from an animal. Ecosystems are made of relationships, not just lists of species.

Notice interactions

Ask what each organism needs

To study an ecosystem, ask: What living things are here? What nonliving conditions shape this place? How might the organisms affect one another? In a pond, plants provide food or shelter for some animals. Animals may eat plants or other animals. Decomposers break down dead material. Water temperature and light can affect which organisms can live there.

A change to one part can affect other parts, although the result may be complicated. If a tree falls, some organisms may lose shelter while others gain a sunny spot or new material to live on. We should observe before deciding what a change will do.

Scientists use observations, drawings, and measurements to learn about ecosystems. One visit gives only a snapshot. Seasons, weather, and human activity can change what is present, so careful observers record when and where they made an observation.

Key takeaways

• A habitat is a place where an organism lives.
• An ecosystem includes organisms, nonliving parts, and their interactions.
• Biotic parts are living or once living; abiotic parts are nonliving.
• Organisms share habitats and depend on environmental conditions.

Practice

Name two biotic and two abiotic parts of a pond habitat. Sample answer: Fish and pond plants are biotic; water and sunlight are abiotic. Many other answers are possible.