Characteristics of the Kingdoms Archaea • differ from the true bacteria in many important respects, as well as from the eukaryotes. These differences include: • The wall structure and chemistry. • The lipids that make up the membrane • The metabolism • Many members of this kingdom are extremophiles that is they live in extreme environments, including water whose temperature exceeds that of boiling water such as hot spring geysers and sub sea vents. • They are very diverse, both in form and function. Some are uni-cellular, while others form colonial arrangements. Eubacteria • The eubacteria are microscopic and relatively simple cells. • They lack the nucleus and organelles of the more complex eukaryotes; however, like the cells of plants, most possess a cell wall. • After the "archae," true bacteria are the oldest type of organism on Earth, and also the most abundant. • They exist in soil, water, and as parasites of other organisms. • Species and strains of bacteria cause many if not most non-hereditary diseases. Protista • The Kingdom Protista or Protoctista is one of the commonly recognized biological kingdoms. They include all the eukaryotes except for the plants, fungi, animals, and sometimes other groups which are • treated in separate kingdoms. There are a few forms that are multicellular, for example the brown and red algae. • Most though are single-celled organisms, and are typically only 0.01-0.5 mm in size, too small to be seen without a microscope. • Protists are widespread throughout wet environments and the soil. • Theyare able to survive dry periods by forming cysts; a few others are significant parasites. • Traditionally they have been separated into: • Plant-like forms that contain chloroplasts, the algae; • Fungus-like forms, the slime molds and water molds; • Animal-like forms, the protozoa, generally divided on the basis of structure These being: – – – – Flagellates (e.g. Euglena) Amoeboids (e.g. Amoeba) Apicomplexa Ciliates (e.g. Paramecium) • The Fungi (singular: fungus) are a large group of organisms. • They include important decomposers and many parasites. • Parasitic fungi infect animals, including us, other mammals, birds, and insects, with results varying from mild itching to death. • Other parasitic fungi infect plants, causing disease such as Potato Blight. • Many vascular plants are associated with mutualistic fungi, called mycorrhizae, which help with the absorption of nutrients and water. Some fungi are used as food, such as mushrooms and truffles; others are very poisonous and can cause death if eaten. • Most fungi have vegetative bodies (called a thallus or soma) that is made up of single cellthick filaments called hyphae. • Generally they do not merge into a visible object, but instead form a microscopic network within the substrate, called the mycelium, through which food is absorbed. • The fungi are absorptive heterotrophs. • The more conspicuous parts of fungi like mushrooms are fruiting bodies, reproductive structures that produce spores. • This term is considerably more difficult to define than we might think. • Our natural inclination is to regard plant as meaning a multicellular, eukaryotic organism that generally does not have sense organs or the ability to move and has, when complete, a root, stem, and leaves. • We have to acknowledge thought that only one group, vascular plants, have "a root, stem, and leaves". • Granted the more common plants that we encounter on a daily basis would be the vascular ones. • Another, much broader (more inclusive) definition for plant is that it refers to anything that is photoautotrophic — that is, it is able to make its own food from light energy. • This is a reasonable definition, and one that focuses on the role plants typically play in an ecosystem. • Yet we must remember that there are photoautotrophs among the Prokaryotes, specifically photoautotrophic bacteria and cyanophytes. These are often referred to as the blue-green algae. Animalia • Animals are the group of organisms that make up the kingdom Animalia. • Usually, they are multicellular and capable of both locomotion and responding to their surroundings. • Unlike plants, animals do not photosynthesize, rather they consume their food: they are ingestive heterotrophs.