Energy is the ability to change or move matter. All living things need energy to do work, whether it is to move from one place to another or carry out basic biochemical processes inside cells. Living things can be classified based on how they obtain energy. Some utilize the energy in sunlight or chemical compounds to make food. While others get energy by consuming other organisms, either living or dead. Energy flows throughout the ecosystems from producers, to consumers, to decomposers.PRODUCERS (AUTOTROPHS):Living things that produce food for themselves and other organisms.These organisms use simple inorganic molecules to make organic compounds.All organisms need organic compounds for energy; hence producers are absolutely necessary to all ecosystems.CONSUMERS (HETEROTROPHS):Organisms that depend on other living things for food.They consume organic compounds by eating or absorbing other living things. Consumers are classified by the type of food they eat; and they may be herbivores, carnivores, or omnivores.Herbivores consume producers such as plants or algae.Omnivores consume animals such as lions and sharks.Carnivores consume both plants and animals such as cows and human beings.DECOMPOSERS:Organisms that break down the wastes of other living things or the remains of dead organisms.As decomposers break down the wastes, they release simple inorganic molecules into the environment for the producers to make new organic compounds.There are several types of decomposers, depending on the type of organic matter they break down; and they may be scavengers, detritivores, or saprotrophs.Scavengers feed on the soft tissues of dead animals. They include hyenas and cockroaches.Detritivores consume dead leaves, animal feces, and other organic debris that collects on the ground; and they include earthworm and catfish.Saprotrophs consume any remaining organic matter or leftover from other decomposer; and they include fungi and protozoa.