Energy Flow Between Organisms - Reading and Diagram (6-8 Grade NGSS)

Plants, algae, and other tiny microorganisms, all depend on sunlight, which they use to produce food. They absorb sunlight, take in carbon dioxide from the atmosphere, and water from their environment. With them, they produce sugars that fuel their every day bodily functions or are stored for later when needed for growth, repair, and reproduction. This is a chemical process called photosynthesis. During photosynthesis, the organisms also release oxygen into the atmosphere.

These organisms which use photosynthesis to make fuel have specialized organelles called chloroplasts. Chloroplasts contain a green pigment, called chlorophyll which traps the light energy needed for photosynthesis. The cells that contain the most chloroplasts are on the upper surface of the organisms, exposed to the sun. The energy absorbed by the chlorophyll changes carbon dioxide and water into sugars, which the plants use, and oxygen, which the plant releases. Photosynthesis is essentially:
 
light + water + carbon dioxide (CO2) = sugars + oxygen (O2)

Plants, algae and other photosynthetic microorganisms, in turn, are consumed by animals (and other organisms). Animals digest and break down this food to use as fuel for their own bodily functions, growth and reproduction.

In this way, the energy of the sun is converted by plants (and other photosynthetic organisms) into fuel that most animals (and other consumer organisms), in millions of food webs all over Earth, can use to survive. The process also releases vital oxygen into the atmosphere.