Kingdom Protista
The protista are the one-celled eukaryotic organisms. As eukaryotes, they have nuclear membranes and linear chromosomes (with associated proteins) that can undergo meiosis and mitosis. The first eukaryotes were unicellular protests, some of which gave rise to the fungi, animals and plants that do not occur on earth today. Modern protists show modes of life that closely resemble higher eukaryotes. Some being photosynthetic, some ingestive, and some absorptive, some motile ,some nonmotile, some with cell walls and some without all combinations of these characteristics are represented in various members of this group.
Kingdom Fungi
The fungi are often classified as plants because they are nonmotile and they have an external wall that resembles the cell wall of plant cells in many ways. Fungi, however, cannot make their own food; they must absorb food from a nonliving organic source. In many cases, they excrete digestive enzymes that digest food outside their bodies before they can absorb it. Whittaker felt that fungi should be separated from plants because they are completely absorptive whereas plants are only secondarily absorptive (that is, plants absorb water and minerals and carbon dioxide, but make their own organic molecules). In addition, fungi and green plants differ in cell wall composition, body plan and reproduction.
Kingdom Plantae (plants)
The members of the plant kingdom are eukaryote and have cell walls that contain polysaccharide cellulose. Most contain chlorophyll and carry on photosynthesis inside chloroplast. Although a few species have lost their chlorophyll and obtain all of their nutrition by absorption [Monotropa, the Indian pipe plant and Sarcodes the snow plant. The plant kingdom includes the multicellular algae as well familiar multicellular land plants-the mosses, ferns, grasses, shrubs and trees. They are, therefore, multicellular eukaryotic autrotrophic embryophytes
Kingdom Animalia (animals)
They are multicellular, eukaryotic, heterotrophic organisms that obtain food by ingestion. Most animals can move and this helps them to acquire food from their environment. All animals produce gametes (eggs and sperm) fertilize and develop into multicellular organisms.
