Kingdom Monera The most numerous and widespread kingdom on Earth. What are monerans? Here are some things that all members of this kingdom have in common. The are all prokaryotic. This means that their cells lack a nucleus and other membrane bound organelles. They are all unicellular, though may form clumps, strands, chains or even layers and colonies. They are asexual. They reproduce by binary fission. History of Monerans This kingdom represents the most ancient type of life on Earth. They were around before there was any oxygen in the atmosphere, in fact, they are responsible the first atmospheric oxygen. We will simply classify this gigantic kingdom in this way. Bacteria, which consists of both germs and cyanobacteria, and the archaea, which are also known as extremophiles. Bacteria It is important to realize that bacteria are everywhere. Virtually every surface in this room is covered by them. You are covered with bacteria. Bacteria even live inside our bodies, but that is not necessarily a bad thing. Bacteria-Human mutualism A certain type of bacteria, E.coli, are naturally found in our intestines. They help us by producing vitamin K, a vitamin we need for proper enzyme function. However, E.coli can make us very sick as well. E.coli is present in our feces, which is why it is so very important to wash our hands after using the facilities. We are outnumbered! Even within our bodies, our cells are outnumbered by bacterial cells 10 to 1. However, bacterial cells are much smaller than our own, so they only comprise a small percentage (3%) of our mass. And remember, our mitochondria were once free-living bacterial cells. Bacterial respiration Not all bacteria utilize oxygen while carrying out respiration. Aerobic respiration is respiration that requires oxygen. Anaerobic respiration is respiration that does not require oxygen. Some types of bacteria are capable of doing both. Extremophiles. The Archaea Archea are capable of surviving and thriving in nearly any condition. We learned about the prokaryotes that live in deep sea thermal vents. Other Archea live in deep caves filled with poisonous gases. Some, like the ones pictured here, surviving in near boiling water. Bacteria and disease. Some types of bacteria are actually beneficial to humans and other forms of life. However, some bacteria can make us very, very sick and can even kill us. Some bacteria make us sick because of the waste products they produce while carrying out their life processes. No members of Archaea are know to cause disease. Pathogenic bacteria. Others, like the flesh eating bacteria actually break down and consume our cells! There are bacteria of this type that affect other animals as well. Diseases Other diseases caused by bacteria are Leprosy Strep throat Meningitis Lyme disease Defense against bacteria. Fortunately we have some defense against bacteria. Antibiotics are drugs which attack bacteria cells but leave our alone. The poke holes through their cell walls! Cyanobacteria These are autotrophic bacteria, once misleadingly called blue-green algae. They are responsible for the first major extinction event on earth as they flooded the atmosphere with oxygen, which was toxic to most life on earth. It is believed that a type of cyanobacteria eventually became the chloroplasts of plant cells by the process of endosymbiosis. Cyanobacteria habitat While they can be found almost everywhere, even on bare rock, most are aquatic, which means they live in water. If conditions are favorable, their populations can explode having negative impacts on lakes. While not nearly as dangerous as some bacteria, some of them can make us sick. The good side of bacteria. The bacteria found in yogurt and other fermented foods help to fight off infections in our intestines. These are called probiotics. Some types of bacteria are helpful in de-toxifying lakes, promoting biodiversity. Bacteria in the roots of plants called legumes convert atmospheric nitrogen into a form usable by plants and animals. These are called nitrogenfixing bacteria. Decomposers Finally, it is important to recognize the role bacteria play in material cycles. Dead and decaying matter, as well as animal wastes are broken down primarily by bacteria. Through decomposition, bacteria break down nutrients and return them to the soil. Once in the soil, they can be utilized by plants. Domains Recently a new level of taxa has been included into our system of classification called the Domain. There are three domains: Archaea: Extremophile monerans. Bacteria: prokaryotes like E.Coli and Strep. Eukaryia: All organisms with eukaryotic cells. 3 Domains of life Did you ever imagine you’d be classed in the same with a lichen, a mushroom or an Algae? Well in this paradigm you are! Cells with nuclei rock! QuickTime™ and a decompressor are needed to see this picture. Review What type of cell is common to all Monerans? What are the two domains populated with prokaryotes? Where can monerans be found? What two types of respiration is utilized by monerans? How do monerans reproduce? Most bacteria are harmful, True or False? Name 3 good things that bacteria do for us.