The Fungi Kingdom consists of plant-like organisms with small nuclei such as yeast, bread mold and mushrooms. Many of the organisms in the Fungi Kingdom can cause disease, but some are helpful as they are used to make things like antibiotics and yeast. Most of the organisms in this kingdom are parasitic and receive nutrients from surfaces they live on.
The fungi kingdom is a very broad diverse group of organisms including things ranging from yeast to mushrooms. They have many characteristics in common. This first of which is that they're all eukaryotes and many of them are multicellular. Of course things like yeast are single cell. They form a characteristic structure called hyphae which are these long thin tubes of cells that often when formed in the soil or wherever to help absorb material, they're called mycelium. They use a very unusual polysaccharide called chitin in their cell walls and this is one of the things that makes them distinct from several other groups. They follow the zygotic life cycle. What does that mean? That means that for the vast majority of the time except when they're doing reproduction, they are haploid or they can sometimes form these; I think it's called heterozygoti-chariotic. That's when you have two nuclei in one cell and this is something that's formed when two fungal cells will merge, but they don't actually merge their nuclei. They wait until it's finally ready to start doing reproduction, then they'll merge and then immediately undergo meiosis to form new reproductive structures called spores. So, they'll release these individual cells and from that one individual cell it'll grow into a whole new fungus. In the environment they're typically decomposers. That's what we think of when we think of a mushroom, but also many of them are symbionts which means that they work together with other creatures and live with them, typically mutualistically. A lot of plants actually have mutualistic symbion fungi living amongst their roots to help absorb additional water for the plant. Then there's a whole bunch of parasites. For example ringworm is actually not a worm. It's actually a fungus that can get into your skin. Now it forms a ring structure but that's because as the fungus starts to grow, they'll start shooting up little sprouting bodies or fruiting bodies so it can shoot out new spore through your skin and that will make this ring of redness. Athletes' foot is another fungal parasite that some of you are unfortunately too familiar with. Some examples of the bigger groups of fungi include the chytridiomycota which are a fungal group that's found primarily in aquatic environments. The zygomycota which are the things that form molds and such like that. The ascomycota are some times called the sack fungi and that's because they'll fork these cup like structures called an ascus and some of them even form puff balls where that sack gets closed up into almost like a bag shape. Then the basidiomycota are the ones that most people are familiar with; those are the mushrooms.