Energy Flow:
* Enters as sunlight: The primary source of energy for most ecosystems is sunlight.
* Producers capture it: Plants and other photosynthetic organisms convert sunlight into chemical energy (sugars) through photosynthesis.
* Passed along food chains: When herbivores eat plants, they obtain energy from the stored sugars. Carnivores obtain energy by eating herbivores.
* Dissipated as heat: At each step in the food chain, some energy is lost as heat during metabolic processes.
* Not recycled: Energy cannot be recycled within an ecosystem. It flows through the system and is ultimately lost as heat.
Nutrient Cycling:
* Finite resources: Nutrients like carbon, nitrogen, phosphorus, and water are finite resources on Earth.
* Constant cycling: These nutrients move through the environment in cycles, being used and reused by living organisms.
* Producers to consumers: Plants absorb nutrients from the soil and water. Herbivores obtain nutrients by eating plants. Carnivores obtain nutrients by eating herbivores.
* Decomposers play a key role: Decomposers (like bacteria and fungi) break down dead organisms and waste products, releasing nutrients back into the environment where they can be used again.
In summary:
* Energy flows through ecosystems in a one-way direction, entering as sunlight and ultimately being lost as heat.
* Nutrients cycle within ecosystems, being constantly reused and recycled by living organisms.
