- Prokaryotes or Monera – the most simple living things: bacteria and archaea
- Protista – eukaryotes that are not plants, fungi, or animals
- Fungi – mushrooms, moulds and other fungi
- Plantae – all plants, such as moss, trees and grass
- Animalia – all animals, including people. See List of animal phyla
Template:Full biological kingdom classification The kingdom-level classification of life is still widely employed as a useful way of grouping organisms. Sometimes entries in the table, which are next to each other, do not match perfectly. For example, Haeckel placed the red algae (Haeckel's Florideae; modern Rhodophyta) and blue-green algae (Haeckel's Archephyta; modern Cyanobacteria) in his Plantae, but in modern classifications they are considered protists and bacteria respectively. However, despite these differences, the table gives a useful summary.
- There is no agreement at present on how many kingdoms there are in the Eukarya. In 2009, Andrew Roger and Alastair Simpson said this: "With the current pace of change in our understanding of the eukaryote tree of life, we should proceed with caution".