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: -Producers, also known as autotrophs, make their own food. They make up the first level of every food chain. Autotrophs are usually plants or one-celled organisms. Nearly all autotrophs use a process called photosynthesis to create “food” (a nutrient called glucose) from sunlight, carbon dioxide, and water.

Detailed explanation-4: -The Sun’s energy is needed for plants to make food through a process called photosynthesis. In photosynthesis, green plants capture the Sun’s energy. They use it to make sugars from water and carbon dioxide. Plants are considered a producer in the food chain.

Detailed explanation-5: -All food chains start with energy from the sun. This energy is captured by plants. Thus the living part of a food chain always starts with plant life and ends with an animal. Plants are called producers because they are able to use light energy from the sun to produce food (sugar) from carbon dioxide and water.