Scientists Say: Ecosystem

Ecosystem (noun, “EE-koh-sis-tem”)

An ecosystem is a network of living and nonliving things interacting in the same place.

The living things in an ecosystem could include animals, plants and microbes. The nonliving things may include soil, water and air. But an ecosystem is worth more than the sum of its parts. Living things need energy and nutrients to live — and ecosystems link organisms to both.

Nutrients are chemicals that living things need to function. They include elements such as carbon and nitrogen. They can also be molecules like proteins that are made from elements. These elements cycle through an ecosystem. For instance, when an animal eats a plant. Or when a microbe decomposes a dead animal. That means the same atoms get reused in different living things. In fact, the same carbon atoms in your body might once have been part of a dinosaur!

Energy doesn’t cycle through living things the way nutrients do. But ecosystems need a constant supply of it. That’s because energy is always being lost. Living things use energy to break down food, grow, recover from injuries and much more.

The sun supplies this energy. Plants and algae use photosynthesis to turn solar energy into chemical energy. This is a key link in ecosystems. Humans and other life-forms can’t use the sun’s energy directly. We need to get it from plants, or from organisms that have eaten plants.

Let’s look at how living and nonliving things interact in one ecosystem: a rainforest.

Giant anteaters (Myrmecophaga tridactyla) live in South American rainforests. There, they dig around in the soil for insects. As they hunt, the animals mix up the soil. That allows air to move deeper underground. (Take note — air and soil are nonliving parts of the ecosystem.)

This process delivers fresh air to microbes that live in the soil and spurs their growth. The microbes chomp away at dead material in the soil. This breaks down large molecules into smaller ones — nutrients — that a plant’s roots can absorb. And as a plant converts the sun’s energy into chemical energy, an insect munching the plant’s leaves can take some of this energy for itself.

Together, all these living and nonliving parts of an ecosystem form a thriving habitat.

In a sentence

Almendro trees use lightning to gain a competitive advantage in their jungle ecosystems.

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