An organism is any living body that is capable of eating, reproducing, performing respiration, and growing. Most, but not all, organisms can also move. There are over 10 million different types of organisms on Earth. Organisms vary in size and can be microscopic to weighing over 100 tons.
Organisms are grouped into two major groups: eukaryotes and prokaryotes. Eukaryotes are made of cells that contain a nucleus and other cell parts called organelles. Animals and plants are in this category of organisms. Prokaryotes contain a cell or cells with no nucleus or major organelles. Bacteria are considered prokaryotes.
Organisms can further be grouped into five different kingdoms based on shared characteristics. The Monera Kingdom is made up of prokaryotic organisms. The Protist Kingdom consists of organisms that are eukaryotic but contain only one cell. Organisms that look similar to plants but cannot make their own food are a part of the Fungi Kingdom. Organisms in the Plant Kingdom make their own food and cannot move while organisms in the Animal Kingdom cannot make their own food and are able to move on their own.