The Five Kingdoms Linnaeus divided up the whole of the living world into two large groups, the "kingdoms" of the plants and the animals. Today we recognize that this is too limiting. Modern hierarchical ordering systems begin by dividing up the whole of the living world into at least 5 kingdoms, but even this may not be enough. Monerans single-celled prokaryotic organisms (no membrane enclosed organelles) with a wide variety of shape, form, metabolism and lifestyle. Includes the "true" bacterial (eubacteria), the cyanobacteria (formerly called the 'blue-green algae'), and the archeabacteria (an ancient form of life some consider to be a 'sixth' kingdom). Protists single-celled eukaryotic organisms (large cells, membrane enclosed internal organelles) including photosynthetic algae, and animal like protozoa. Many lifestyles including mixtures of animal, plant or fungal characteristics. Very heterogeneous. Slime molds are often included in this kingdom. Plants multicellular eukaryotic organisms that have cellulose cell walls and membrane enclosed photosynthetic organelles that trap the energy in sunlight and convert it to chemical energy. Autotrophic. Animals multicellular eukaryotic organisms that ingest food particles and obtain their energy and building materials from pre-formed organic molecules and materials. Heterotrophic. Fungi nonmotile eukaryotic structures with cell walls that obtain energy and nutrients by external digestion followed by absorption. Filamentous forms may have many nuclei and may or may not be divided by cross walls.