Unit A

Module 1 ~ Lesson 1

 Energy Flow in Ecosystems

Energy flows one way through an ecosystem. It is not recycled. Matter cycles through an ecosystem. Only producers are able to capture the Sun's energy. Consumers then use the energy captured by producers.

Due to the second law of thermodynamics, energy is lost to less usable forms as it flows through the ecosystem. Producers provide energy directly to primary consumers (herbivores), who are then consumed by secondary consumers (omnivores or carnivores) and so on until an apex predator dies and decomposing organisms use the remaining energy in the carcass.
The solar radiation budget helps to explain the distribution of the Sun's energy.
The amount of solar energy absorbed by a surface depends on its albedo.
Albedo is a measure of the percentage of solar energy that is reflected from a given surface. The higher the albedo, the less energy that is absorbed by that surface. The albedo of features within an ecosystem have an impact on the type and number of organisms that will reside in that ecosystem. For example, the albedo of ice and snow is much higher than the albedo of a forest, resulting in less absorbed energy in frozen environments. If soil begins to be uncovered, more energy will be absorbed, warming that climate.


Read "A Closer Look at Consumers" and "The Fate of Energy in the Biosphere" on pages 12 to 15 in your textbook.