• Energy is essential for maintaining order in ecosystems and living systems.
• Natural systems require a continuous input of energy to replace what is lost as heat during various processes.

• Ecosystems cannot function in isolation; they need energy input for work to replace the dissipated energy.
• One way energy enters an ecosystem is through sunlight, which is captured by producers (plants) during photosynthesis.
• Photosynthesis converts sunlight energy into chemical energy, stored in the producers as biomass.

Example: Imagine a group of plants in a garden. These plants absorb sunlight to make their food (sugars) through photosynthesis. This energy from the sun is now stored in the plants and is ready to be passed along the food chain.

• The energy entering an ecosystem (e.g., through sunlight) is equal to the energy leaving it.
• This law ensures that energy is conserved within the system.

Example: Think of a closed jar with a light bulb inside. The energy produced by the light bulb stays within the jar, and the total amount of energy remains the same unless the jar is opened, allowing the energy to escape.

• The available energy is used to perform various tasks such as growth, movement, and creating complex molecules.
• However, the transformation and transfer of energy are not 100% efficient (Second Law of Thermodynamics).
• When energy is converted from one form to another, some of it is lost as heat, making the process less efficient.
• This energy dissipation means there's less usable energy available for work.

Example: Imagine a car engine. When fuel is burned to produce energy, not all of it is converted into useful energy for the car's movement. Some is lost as heat, sound, and other inefficiencies.