Energy and Nutrients in Ecosystems

Energy Flow in an Ecosystem

From your studies of photosynthesis and respiration, you already know that that energy flows from organisms that create their own food, or autotrophs, to those organisms that eat autotrophs. This energy flow forms a complex web. Learn more about how energy travels through an ecosystem in this interactivity. Click the player button to begin.

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Food webs also allow ecologists to study the different trophic levels, which are the different levels of nutrient absorption in a food chain or web. The simplest food chain includes a producer, a primary consumer, and a secondary consumer. The primary consumer is an herbivore or omnivore. There can be many levels of consumers. The secondary consumer is an omnivore or carnivore, as is the tertiary consumer. Ecosystems with a variety of organisms are more stable – or homeostatic – and thus less likely to succumb to threats than an ecosystem with few organisms.

The flow of energy through a system is not efficient. When biomass, or the total organic mass of organisms in a specific area, is consumed by heterotrophs, only about 10% of the energy is used to make new biomass. Essentially, 90% of the energy is lost at each level as it moves up a food chain. Because of this, it takes more biomass, energy, and number of producers and primary consumers to support secondary and tertiary consumers.

Pyramid Diagrams

The flow of energy in an ecosystem can be represented in a variety of ways. One of the most popular ways is through a pyramid diagram because it is a depiction of how the level of energy diminishes as it moves up a food chain. In this interactivity, learn more about three of these pyramid types - energy, biomass, and numbers.

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Cycles in Ecosystems

Ecosystems are built on the cycling of matter, including nutrients. There are three main cycles that impact living things in ecosystems - the water cycle, the carbon cycle, and the nitrogen cycle. Each cycle is outlined in the interactivities below.

The Water Cycle

The water cycle is a never-ending process that results in the movement of water from one location to another. As water moves throughout the Earth’s surface and atmosphere, it undergoes several phase changes. View this presentation to learn the parts and processes involved with the water cycle. Click the player button to begin.

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The Nitrogen Cycle

The nitrogen cycle is important to life on Earth, as it acts as a source of energy for producers in ecosystems. In this interactivity, learn more about the nitrogen cycle by clicking on each of the spinning icons. Click the player button to begin.

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The Carbon Cycle

All organisms, including you, need carbon. It makes up many key components of the body. In this interactivity, learn more about the carbon cycle by clicking on each of the spinning icons. Click the player button to begin.

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Energy and Nutrients in Ecosystems Review

Now that you have explored how energy and nutrients flow through an ecosystem. Read each statement and drag and drop then term into the blank provided. Then, click SUBMIT to check your response. Click the player button to get started.