The fascinating world of fungi


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The fascinating world of fungi

  1. 1. The Fascinating World of Fungi Fungi are.......... extraordinary organisms which are neither plants, nor animals. one of the most important group of organisms on this planet some of the world's largest and possibly oldest individuals fairy rings, right out of children's story books hallucinogenic magic mushrooms some are silent killers with deadly poisons. a vital ingredient in beer and bread. decomposers, essential for natural recycling, helping to guarantee life on earth. miracle cures for disease. indispensible partners for many plants. Classification Fungi are divided into three main phylums based on how related they are to each other and shared reproductive habits. These phylums are: Basidiomycota, Ascomycota, and Zygomycota. Basidiomycota are characterized by the presence of basidia and dikaryotic fruiting bodies and include: mushrooms, puffballs, and shelf fungi. Ascomycota are a diverse group and are characterized by the presence of asci. They include: the cup fungi and mildews as well as the unicellular fungi, yeast. Zygomycota are characterized by the presence of a thick-coated zygospore and
  2. 2. Types of Fungi Introduction There are literally thousands of different kinds of fungi. Two hundred thousand species have been identified world wide and there are likely to be well over a million species. We identify different species mostly by the structure of their fruiting bodies and the arrangement and types of spores which they produce. There are a great many fungi which are very small (microfungi). They will not be covered here. However, there are many other fungi with large enough fruiting bodies to be easily seen. There are over 3000 of these larger fungi in Britain. Many fungi have fruiting bodies e.g. a mushroom which are stalked. This helps to raise the spores some distance off the ground, so that when they are released, they can easily catch wind currents and be carried to new places. Fruiting bodies of fungi will generally produce millions of spores. A single fruiting body like a mushroom, may produce more than 10,000 million spores! Even though they are tiny, finding room for all these spores on a relatively small fruiting body presents a major problem. The fruiting bodies of fungi are therefore cleverly engineered to provide space for the production of enormous numbers of spores, without having to produce an enormous fruiting body to accommodate them all. Different types of fungi have accomplished this in different ways.
  3. 3. Fungi such as mushrooms, have hundreds of paper-thin folds, called gills, on the underside of the mushroom cap. The spores are produced all over these gills, which provide an enormous surface area base for the spores. Gills are sometimes also known as lamellae. Some other fungi have small tubes or pores within the fruiting body. The spores develop all over the inside of the pores, which again help to produce a large surface area. Still other fungi have developed fruiting bodies covered with enormous numbers of tooth-like structures which bear the spores. Others just have large numbers of folds all over the fruiting body. All of these different methods for increasing surface area of the fruiting body and the different structures which result, provide a useful way to identify different kinds of fungi. How do fungi feed? Fungi cannot make their food from sunlight, water and carbon dioxide as plants do, in the process known as photosynthesis. This is because they lack the green pigment known as chlorophyll, which plants use to capture light energy. So, like animals, they must obtain their food from other organisms. They do this in three ways. They may break down or 'rot' dead plants and animals. Organisms which obtain their food this way are known as 'saprophytes'. Alternatively they may feed directly off living plants and animals as 'parasites'. A third group is associated with the roots of plants in what are termed mycorrhizae.
  4. 4. Basidiomycetes and Ascomycetes Fungi with sporophores (fruiting bodies) large enough to be readily visible will usually belong to one of two main groups. The Basidiomycetes or the Ascomycetes. The main difference between these two groups is in the way in which they produce their microscopic spores. In the Basidiomycetes, the spores are produced externally, on the end of specialised cells called basidia. In Ascomycetes, spores are produced internally, inside a sac called an ascus. Asci and basidia are both microscopic structures. Basidiomycetes Ascomycetes Fungi with spores produced externally, on specialised cells called basidia. Fungi with spores produced inside a sac called an ascus. Typically, there are 4 spores per basidium, although this varies from 1 to many, depending on the species. Each ascus usually contains 8 spores (sometimes 4, depending on the species). For micrograph pictures of basidia and spores Basidiomycetes Within the Basidiomycetes, there are three main groups. These are separated by means of differences in the basidia and spores and how these are arranged on the fruiting body.
  5. 5. Gill Fungi (Order Agaricales and Russulales) Boletes(Order Boletales) Polypores, Chanterelles, Coral Fungi, Crust Fungi, Fan Fungi and Toothed Fungi (Order Aphyllophorales) Stinkhorns (Order Phallales) Puffballs and Earthstars (Order Lycoperdales and Tulostomatales) Earthballs (Order Sclerodermatales) Bird's Nest Fungi (Order Nidulariales) Jelly Fungi(Order Tremellales) The basidia develop in layers, called a hymenium, lining gills, tubes, teeth or folds on the fruiting bodies. Basidia are enclosed inside the Basidia in a hymenium or layer fruiting body. on the outer surface of the fruiting bodies. Asymmetrical spores, which are shot off simple basidia. Symmetrical spores, not shot off the basidia. Holobasidiomycetes Gasteromycetes The basidia are divided internally - there are various different forms. heterobasidiomycetes