An organism is a living entity composed of many interrelated components that work together to achieve a common goal. Organisms come in a wide variety of sizes, shapes and lifestyles, but they all share some similar traits. All organisms require food and excrete waste, grow, reproduce and, ultimately, die.
Animals are the most obvious types of organisms. Animals are the most mobile and active of the organisms, and they include such species as humans, sharks and ants. Each has evolved survive in their particular niche.
Plants are one of the largest groups of organisms, and they form an important part of the food chain. Plants are called “the producers” of the living world, as they harness sunlight and turn it into a form of chemical energy. Called photosynthesis, this process enables the entire food chain to function.
Bacteria are some of the most numerous organisms, as they live on virtually every surface on planet Earth. Bacteria are very simple organisms, and their direct ancestors may have been some of the earliest forms of life. Many bacteria are beneficial and necessary for life, while others can be very harmful. Other types of organisms include protozoa, algae and fungi. Scientists disagree over whether viruses are organisms.