The Food Pyramid Third level consumers, such as birds, eat the second level consumers. Second level consumers, such as fish, eat the plant eaters. First level consumers, such as black fly and mayfly larvae and snails, eat the plants and algae. Algae and other plants produce their own food from the sun's energy. All energy for life comes from the sun.
Plants photosynthesize light energy into chemical energy in the form of carbohydrates.
This energy passes through the ecosystem by being eaten and is refered to as the food pyramid. Therefore there are fewer animals at each higher level. So there are more larvae than fish and more fish than birds. Only a small part of the energy absorbed by plants follows the food grazing web. Plants and animals not used in the grazing food chain are part of the decomposer food chain.