⏳ Estimated Reading Time: 2 - 4 minutes

Explain how energy flows and matter cycles through trophic levels.

Ecosystem Energy Structure

an image of Biotic Factors: Living elements in an ecosystem—plants, animals, and bacteria—exist within their habitat, and Abiotic Factors: Non-living elements—rocks, water, clouds, weather, temperature, humidity, and sunlight — ***Ecosystems are composed of all of the biotic, living, and abiotic, nonliving, things within the ecosystem.***

Almost all ecosystems on Earth begin with the sun. Organisms that get their energy from the sun and conduct photosynthesis are known as primary producers, or autotrophs. Most autotrophs or primary producers are green plants.

an image labeled "producers vs. consumers" with a tree, grass, and algae with the text "producers: produce their own food through photosynthesis" and a rabbit (herbivore), lion (carnivore), and bear (omnivore), with the text, "consumers: obtain their energy from eating plants and other animals" — ***Producers make their own food (usually through photosynthesis) and consumers obtain energy from eating other organisms.***

Trophic levels are the levels at which biotic organisms feed.

If an organism cannot make its own food is known as a heterotroph. Organisms that feed on plants are known as herbivores, or primary consumers. An example of a primary consumer is a cow or a rabbit.

Organisms that feed on herbivores are known as carnivores, or secondary consumers. An example of a secondary consumer is a fox. Organisms that feed on secondary consumers are known as tertiary consumers, and so on.

Organisms that feed on dead or decaying organisms are known as detritivores and provide a way for nutrients to be recycled. Bacteria, fungi, and some insects are examples of detritivores.

When you put all of this together, you have a food chain or a food web, depending on the complexity (we will talk more about these in the next lesson).

a simple food chain vs a complicated food web with the text: Food Chain: shows the feeding relationships between organisms. Food Web: consists of several food chains in a single ecosystem."

In terrestrial and near-surface marine communities, energy flows from the sun to producers in the lowest trophic levels and then upward to higher trophic levels.

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