Ecosystems 101

Every living thing on Earth — from the tiniest fungus to the largest whale — plays a part in keeping our planet alive and thriving. These living beings, together with the air, water, soil, and sunlight around them, form what we call ecosystems.

An ecosystem is simply a community of living things interacting with their environment. Each part matters. Plants turn sunlight into energy. Animals depend on plants for food and shelter. Decomposers like fungi and bacteria recycle nutrients back into the soil. Even elements like wind and temperature shape how the system works.

When all these parts are in balance, the ecosystem stays healthy.

Understanding the Web of Ecosystems

Every ecosystem is a network of living things - plants, animals, fungi, and microbes, interacting with the air, water, and soil around them. Though they look very different, all ecosystems share the same building blocks: energy flow, nutrient cycling, and balance.

Aquatic ecosystems include both marine (saltwater) and freshwater systems. Oceans, rivers, lakes, and wetlands are all part of this watery world that covers over 70% of Earth’s surface.

Terrestrial ecosystems make up the land-based environments - deserts, forests, grasslands, and tundra, each shaped by climate, soil, and elevation.

Every system is connected. Water evaporates from oceans to form clouds that nourish forests. Rivers carry nutrients from land to sea. Animals migrate between habitats, spreading seeds and maintaining balance.

No matter the type, each ecosystem depends on the others, forming one vast, living web that sustains life on Earth.

How Ecosystems Work

Every ecosystem runs on energy and cycles.

Energy Flow

The sun powers everything. Plants (producers) capture sunlight through photosynthesis. Herbivores eat plants, carnivores eat other animals, and decomposers break down what’s left - sending nutrients back to the soil.

Nutrient Cycles

Unlike energy, nutrients are constantly recycled. Carbon, nitrogen, and phosphorus move between soil, water, plants, and animals, with decomposers returning them so new life can grow. When these cycles are disrupted, ecosystems can lose fertility and species can struggle.

Biodiversity

The variety of life within an ecosystem helps it stay resilient. A forest with many species can better recover from drought or disease than one with just a few.

When biodiversity thrives, so does everything else.

Why Ecosystems Matter

Ecosystems are more than beautiful - they’re essential to life. They provide:

Clean air and water through natural filtration

Food and medicine for humans and animals

Pollination for crops and wild plants

Climate regulation by storing carbon and moderating temperature

Recreation and connection, offering peace, inspiration, and wellbeing

Healthy ecosystems also support human health. When natural systems are disrupted - through deforestation, pollution, or climate change - it can increase risks of disease, food insecurity, and natural disasters. (You can learn more about these links on the One Health page.)

When Ecosystems Are Out of Balance

Because everything is connected, damage in one area ripples outward.

Removing one key species can throw an entire system off balance.

Pollution and invasive species can alter water quality and native habitats.

Climate change shifts weather patterns and threatens species that can’t adapt quickly.

For example, when wetlands are drained, birds lose nesting areas, fish lose breeding grounds, and nearby communities lose natural flood protection. Every loss weakens the web of life that sustains us all.

What You Can Do

You don’t have to be a scientist to protect ecosystems. Here are four ways to make a real difference:

Plant & Restore

Grow native plants or support habitat restoration projects in your community.

Reduce Pollution

Use less plastic, recycle, and avoid harmful chemicals that can enter waterways.

Support Sustainable Practices

Choose sustainable food, forestry, and fishing practices to protect biodiversity.

Learn & Share

Explore local ecosystems, educate others, and get involved with conservation efforts.

All ecosystems — from oceans to forests to tiny backyard gardens — are connected and essential for life.

By understanding them and taking small actions, we can help keep our planet healthy and resilient.

Resources

Australian Museum - What is an ecosystem?
National Geographic – Biomes, Ecosystems, and Habitats
Earth How - 7 Types of Ecosystems

Check out my blog to learn more and dive even deeper into these topics — from pollinators and ocean ecosystems to climate impacts and conservation success stories.