What Are the Five Kingdoms in the Classification System?

The five kingdoms in the classification system of life are animals, plants, fungi, prokaryotes and protoctists. Organisms are classified according to various characteristics that they share, and the kingdom classification is based on their cells. The kingdom is the first division of living organisms.

Animals are multicellular creatures that feed on other organisms. Their cells don't have a cell wall. The animal kingdom includes mammals, reptiles, birds, amphibians, fish, echinoderms, arthropods, mollusks, worms and jellyfish.

Plants produce nutrients through a process called photosynthesis, and they have cellulose cell walls. The plant kingdom includes algae, ferns, mosses, conifers and flowering plants. Fungi have chitin cell walls, and they use spores to reproduce instead of seeds. The fungi kingdom includes molds, yeast and mushrooms.

Prokaryotes are organisms that have cells with no nucleus. Their cells do have cell walls that aren't made out of cellulose. The prokaryote kingdom includes blue-green algae and bacteria. Protoctists are single-celled organisms, and the kingdom includes the amoeba and paramecium.

There are multiple divisions that help to further classify life. The divisions under kingdom are phylum, class, order, family, genus and species. The divisions in the classification system are based on many factors, including bone structure, diet and the ability to interbreed.