Energy Flow
Energy Flow
Concept of Energy Flow
- Every ecosystem has a certain flow of energy from one trophic level to the next.
- The source of this energy in most ecosystems is the sun.
- Organisms called producers convert sunlight into chemical energy through a process known as photosynthesis.
- The energy then moves through the ecosystem from producers to consumers.
Food Chains and Webs
- Energy flow in an ecosystem can be represented with diagrams known as food chains and food webs.
- A food chain shows a simple, linear path of energy flow from one organism to the next.
- A food web is more complex, showing multiple interconnecting food chains.
- Each step in a food chain or web is known as a trophic level.
- Despite their complexity, food webs help illustrate that all life in the ecosystem is interconnected.
Energy Transfer
- Energy is transferred up the food chain from producers to the first level of consumers (typically herbivores), and from there to higher levels of consumers (carnivores and omnivores).
- However, not all consumed energy is transferrable to the next trophic level.
- Most of the energy is used by organisms for their metabolic processes, and the rest is lost as heat.
Efficiency of Energy Transfer
- Energy transfers are usually about 10% efficient - that is, about 10% of the energy at one trophic level is passed on to the next.
- This inefficiency limits the length of food chains. There typically are not enough energy available to support large numbers of high-level consumers.
- As a result, ecosystems usually have many more individuals at lower trophic levels than at higher ones.
Role of Decomposers
- Decomposers, such as bacteria and fungi, break down the bodies of dead organisms and waste materials into simple nutrients.
- These nutrients are returned to the soil or water for use by producers, continuing the cycle of energy flow.
- Thus, decomposers play an important role not only in recycling nutrients but also in enabling continuous energy flow.
Human Impact on Energy Flow
- Human activities, such as deforestation and pollution, can disrupt the energy flow in ecosystems.
- These disruptions can lead to declines in biodiversity, reductions in ecosystem health, and changes to the natural equilibrium.