19.1) Energy flow
Nearly all living things depend on the Sun to provide energy. This is harnessed by photosynthesising plants and the energy is then passed through food chains.
- With the exception of atomic energy and tidal power, all the energy released on Earth is derived from sunlight.
- The energy released by animals comes, ultimately, from plants that they or their prey eat and the plants depend on sunlight for making their food.
- Photosynthesis is a process in which light energy is trapped by plants and converted into chemical energy (stored in molecules such as carbohydrates, fats and proteins).
- Since all animals depend, in the end, on plants for their food, they therefore depend indirectly on sunlight.
- Eventually, through one process or another, all the chemical energy in organisms is transferred to the environment.