AP BIOLOGY

Detailed explanation-1: -The vast majority of energy that exists in food webs originates from the sun and is converted (transformed) into chemical energy by the process of photosynthesis in plants. A small proportion of this chemical energy is transformed directly into heat when compounds are broken down during respiration in plants.

Detailed explanation-2: -3.1 The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers such as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs.

Detailed explanation-3: -Energy enters most ecosystems as sunlight, but the rest enters the ecosystem through producers!

Detailed explanation-4: -Primary producers use energy from the sun to produce their own food in the form of glucose, and then primary producers are eaten by primary consumers who are in turn eaten by secondary consumers, and so on, so that energy flows from one trophic level, or level of the food chain, to the next.