03.01 Energy and Living Systems

Energy and Living Systems: Summary

-All living systems must maintain a balance of disorder and entropy with processes that maintain and increase order. For example, biological systems pair processes that increase entropy (and so have negative changes in free energy) with those that decrease entropy (and so have positive changes in free energy) to maintain such a balance. For all living systems, the free-energy input must exceed the amount of free energy lost to entropy to maintain order and power biological processes. -Energy availability is essential for supporting populations and ecosystems as well. Changes in free-energy availability can result in changes in population size and disruptions to an ecosystem. For example, a change in the producer level of an ecosystem can affect the number and size of all other trophic levels.

Energy and Living Systems

All forms of life require a highly ordered system. Such order is maintained by constant flow of free energy into and out of the system. The organized flow of energy and matter is important at all levels of life, from cells to ecosystems.

Consuming Different Trophic Levels

The available amount of usable energy decreases from one trophic level to the next. This is generally accompanied by a smaller number of organisms at the higher trophic levels. Let's use some general data to compare how consuming different trophic levels can affect energy availability.

Energy and Living Systems

The general flow of energy is from producer to primary consumer to secondary consumer to tertiary (third-level) consumer. This is a model, so it may not reflect every ecosystem in terms of number of trophic levels. The biomass decreases as you move up the pyramid. Only a small amount of energy (typically about 10%) at one trophic level moves to the next trophic level.