AP BIOLOGY

Detailed explanation-1: -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-2: -Essential idea: Ecosystems require a continuous supply of energy to fuel life processes and to replace energy lost as heat. The image above shows an eruption on the surface of the sun. Without a constant stream of solar radiation much of the life on Earth would not be possible.

Detailed explanation-3: -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.

Detailed explanation-4: -The form of energy that living things need for these processes is chemical energy, and it comes from food. Food consists of organic molecules that store energy in their chemical bonds.

Detailed explanation-5: -The energy flow takes place via the food chain and food web. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis.