During photosynthesis, a plant - whcih is a producer - absorbs
light energy from the sun and converts it into glucose, which is
what the plant uses for energy. Some of the energy that the plant
made may be released into the atmosphere as heat, some will be
eaten by insects and other herbovores, which are called primary
consumers. Secondary consumers may eat the primary consumers,
getting energy from eating them. Consumers get energy by eating
other consumers or producers.