Fungi

= FUNGI (pronounced fun-guy) =

By: Michelle Shknevsky

=
//I'm doing a project on a fungi. But see, there are so many "fungi's" in the world. So, should I do it on Mr. Dixon? How's about Chuck Norris? I think Chuck Norris will do. But really, I'll just do it on a legitimate fungi. Sorry Mr. Dixon. And sorry to you too, Chuck Norris. I wonder if he’s sad that I’m not doing a project about him in AP Biology. Then again, Chuck Norris is never sad… Because secretly, Chuck Norris is the oldest fungi out there.//======

__Diagnostic characteristics of the group__
-Fungi have their own kingdom. They are eukaryotes and multicellular organisms. Although people have closely associated them with plants, fungi are more related to animals because of their nutritional mode, structural organization, growth, and reproduction. Several proteins and ribosomal RNA show that animals are more related to fungi than plants. -"Fungi are heterotrophs that obtain nutrients through the process of absorption; small organic molecules are absorbed from the environment. Some fungi are pathogens. Most likely evolved from a protistan ancestor. Cells contain membrane bound nuclei and organelles within a cytoplasm." (CW)(3) -"There are several different ways in which fungi absorb nutrients. Saprophytic fungi obtain nutrients by secreting enzymes that break down dead organic matter (found in the soil.) Other fungi are parasites, which means that they get nutrients from a living host." (RG) [8]



-By molecular evidence, it is shown in this image that fungi was separated into four branches. The flagella, as shown, only appeared in the ancestor of the fungi called **Chytrids**. The flagella cells were most likely lost in the chytrid lineage which then led to the **Zygote** fungi, which became more adapted to land, whereas the chytrid was more of an aquatic fungi. These fungi may have diverged during the transition from aquatic to terrestrial habitats. 

__**Major types **__
//There are more than 10,000 different species known, and 1.3 million worldwide. There are four major types of fungi: Chytrids, Zygote fungi, Sac fungi, and Club fungi.//

//**Chytrids**//:
-The **chytrids** mainly live in an aquatic environment and act as either saprobes, living on the remains of their food, or parasites, living within their host. Scientists have recently associated chytrids into the kingdom Protista because of its flagella, which makes this category of fungi completely different from the others. The chytrids have an absorptive mode of nutrition and cell walls made of **chitin**, a nitrogen-containing polysaccharide that forms a semitransparent horny substance and is very important to the exoskeleton. Molecular evidence also supports that the chytrids are the most primitive of all the fungi which means that they diverged earlier than any other fungi. -There are about 600 types of **zygote fungi.** This type of fungi can live on soil or decaying plant. One of the most major forms of a zygote fungus is **mycorrhizae**, which are mutualistic associations with the roots of plants. Black bread mold is a type of zygomycete that absorbs nutrients by spreading its **hyphae,** tiny filaments, over the food. The **zygosporangia** are resistant to drying and freezing. When conditions get better, the zygosporangia release haploid spores. Some zygomycetes can aim their spores, such as the //Pilobolus//.
 * //Zygotes: //**



//**Sac Fungi: **// -As for **sac fungi**, there exist over 60,00 species from a variety of marines and freshwater habitats. About half of the ascomycetes, or sac fungi species live with algae mutualistically called lichens. Some form mycorrhizae with plants. The one feature of the ascomycota is the production of sexual spores in saclike **asci**. Most sac fungi bear their sexual stages in macroscopic fruiting bodies called **ascocarps**. Ascomycetes reproduce asexually by producing asexual spores which are carried by the wind. The spores produced externally on the tips of the hyphae called **conidiophores.** These naked spores are called **conidia.** A **lichen** is a type of ascomycete and basidiomycete. It's a mesh of fungal hyphae that holds photosynthetic microorganisms. //**Club Fungi: **// -The last type of fungus, called club fungi or the phylum Basidiomycota, contains about 25,000 different species. **Basidium**, the root of the phylum, means little pedestal, which refers to how this type of fungi reproduces. The clublike structure of this fungi gave rise to the name **club fungus**. This type of fungus is a very important decomposer of wood and other materials. Of all of the fungi, the saprobic basidiomycetes are the best at decomposing complex polymer lignin, an abundant component of wood. Basidiocarps are fruiting bodies that are produced in response to an environmental stimuli. For example, a mushroom is a basidiocarp that has a cap which supports and protects a large part amount of basidia on gills. Because the growth of the mushroom is concentrated on the hyphae of a mushroom, a basidiomycete mycelium, the feeding network of a fungus, can make the fruiting structures in a few hours.



//**--Cool Fact Alert!--**: "The legendary explanation of these circles of fungi is that mushrooms spring up where fairies have danced in a ring on moonlit nights. Afterward, the tired fairies sit down on the mushrooms, but some of the mushrooms are sat on by toads. The mushrooms the fairies choose are edible by humans, but the "toadstools" are poisonous." //

//media type="youtube" key="OeCVdLHB5dY?fs=1" height="340" width="560"(MLK) //

**__<span style="font-family: Georgia,serif;">Basic Anatomy __**
<span style="font-family: Georgia,serif;">-Except for yeasts, which are unicellular, the bodies of fungi are constructed by **hyphae**. Hyphae are composed of tubular walls that surround the plasma membranes and cytolplasm. The haphae woven together, form a mat called a **mycelium.** The majority of fungi are multicellular with hyphae divided into cells by cross-walla, or **septa**. These are generally large enough to let ribosomes, mitochondria, and even nuclei flow from cell to cell. "Hyphae are one-cell thick tissue that also serve as vascular channels along which nutrients are passed. The absence of septa within hyphae is called coenocytic." (AK) (2) T <span style="font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">h <span style="font-family: Georgia,serif;">e cell walls of fungi differ from plants because they are made of chitin. Some fungi's are not divided into cells by cross-walls. **Coenocytic** fungi consist of a cytoplasmic mass with thousands of nuclei. Some parasitic fungi have nutrient absorbing hyphal tips that cut through the tissues of the host called **haustoria**. The mycelium grows rapidly because proties and other matierals are channeled by cytoplasmic streaming to the tips of the hyphae. The surface of the fungi grows larger because it focuses all of its energy on adding hyphal lengths. Because fungi cannot run, fly, or swim, it can extend its hyphae into other places.

(9)(SM) <span style="font-family: Georgia,serif; line-height: 0px; overflow: hidden;">

__<span style="font-family: Georgia,serif;">Transport of Materials __
<span style="font-family: Georgia,serif;">Fungi are heterotrophs that recieve their nutrients through **absorption**, a process of absorbing surrounding protiens from a medium. **Exoenzymes** decompose complex molecules to the point where the fungus can absorb and use. The absorption connects to the role of fungi as <span style="font-family: Georgia,serif;">decomposers and symbionts. Saprobic fungi absorb nutrients from detritus and in this process decompose organic material. There are parasitic fungi that absorb nutrients from the cells of the living hosts as well. Some of these fungi can infect the human lungs, such as pathogenic fungi. They cause about 80% of plant diseases. As for mutualistic fungi, they absorb nutrients from a host organisms, but they also somehow benefit their partners by for example, aiding a plant with the uptake of minerals. "Fungi must “eat” the food wherever they grow: if the food is soluble they can simply absorb the food but if it is insoluble then they must breakdown the complex molecules into simpler ones. The basic difference between how fungi digest food and how we digest food is that we eat food then digest it while fungi digest the food then they eat it" (SD) (5). "Multicellular fungi are made up of special filaments known as hyphae. Hyphae possess walls within them known as septa. Septa split the hyphae into different cells. Cytoplasm is allowed to flow between septa through spores, and this cytoplasmic flow aids in the transport of materials". (NI) [|4]

__<span style="font-family: Georgia,serif;">Reproduction __
<span style="font-family: Georgia,serif;">The life of a fungi depends on the type of fungi. Below is a picture of the general life cycle of fungi.

<span style="font-family: Georgia,serif;">As you can see, fungi are capable of reproducing both sexually and asexually by releasing spores. The spores are carried by wind and if they land on a moist place with food, the mycelia will be produced. Airborne spores have been found about 100 miles above earth, and is the cause for fungi growing all over the world. The nuclei of hyphae and the spores of most species are haploid, except for transient diploid stages that form during sexual life cycles. Some mycelium may become heterogeneous due to the fusion of two hyphaes of genetically different nuclei, called heterokaryon. This may be beneficial to some fungi because it may compensate for some harmful mutations in the nucleus. The union of two partners usually occurs in two stages called plasmogamy and karyogamy. Plasmogamy is the fusion of two parents' cytoplasm when their mycelia come together, where as karyogamy is the fusion of the two haploid nuclei. During the separation of both processes, the haploid nuclei are still separate and exist as a heterokaryon. In some types of fungi, the haploid nuclei pair off two to a cell and are called dikaryotic. In most fungi, zygotes are the only diploid stages in the life cycles. After the zygote goes through meiosis, it restores the haploid condition before the structures of mycelium produce spores. <span style="font-family: Georgia,serif;">Below are the types of reproduction in three of four of the major types of fungi. __<span style="font-family: Georgia,serif; font-size: 14px; line-height: 21px;">**﻿****Environmental Adaptations** __ <span style="font-family: Georgia,serif; font-size: 14px; line-height: 21px;"><span style="font-family: Georgia,serif; font-size: 13px; line-height: 19px;">Fossils of fungi that date back to almost 460 million years ago show signs of being depended on as decomposers and **symbionts,** an organism living in a state of symbiosis. So it seems as if fungi were growing at the same time that plants moved into the land of the fungi. Fungi themselves are well adapted as decomposers, which greatly benefits the environment around them. The problem is, fungi also attack our food and other various needed elements in our lives, such as walls. Fungi can decompose walls, and even some plastics. Fungi are also considered to be agricultural plants because of how fast they decompose objects and reproduce. There are also types of fungi that attack plants, making the plants poisonous for us. There have been epidemics that have killed thousands of people, such as the epidemic in 944 A.D. that killed more than 40,000 people in France. The general name for a fungal infection is mycosis. Ringworm is a type of fungal infection. There are also types that can spread through the body, two of which are called histoplasmosis and coccidioidomycosis, which are both very serious with tuberculosis-type symptoms. But, fungi also provide us with a lot of different types of food, other than mushrooms. Yeast is probably one of the most important fungi in food production. **Yeasts**, unicellular fungi that inhibit liquid or moist habitats, are used in baking, brewing, and winemaking. "Despite their large habitat areas, many fungi appear to be limited in their range by geographic factors, such as oceans and other large bodies of water, and relationships with other organisms--a species of fungus may be restricted by the range of its host species or one with which it shares a symbiotic relationship." (KS)

<span style="font-family: Georgia,serif; font-size: 14px; line-height: 21px;">media type="youtube" key="XuKjBIBBAL8?fs=1" height="385" width="640" <span style="font-family: Georgia,serif; font-size: 14px; line-height: 21px;">Parasitic Fungi (JS) [|(7)]

<span style="font-family: Georgia,serif;"> Review Questions: <span style="font-family: Georgia,serif;"> 1. Describe the major characteristics of the four major types of fungi and how they are advantageous to the survival of each type. (DB) <span style="font-family: Georgia,serif;"> 2. How do fungi absorb nutrients from the environment and transport these materials? (CC) <span style="font-family: Georgia,serif;"> 3. Is fungi more closely related to animals or plants? Describe the characteristics in common. (AC) <span style="font-family: Georgia,serif;"> 4. How are fungis able to reproduce? Please describe the process. (MP )

<span style="font-family: Georgia,serif;">Sources: <span style="font-family: Georgia,serif;">1. Campbell, Neil A, and Jane B. Reece. Sixth Edition. San Fransisco: Pearson Education, Inc, 2002. [This is the source for all unsourced pictures and information given] <span style="font-family: Georgia,serif;">2. [] <span style="font-family: Georgia,serif;"> 3. [] <span style="font-family: Georgia,serif;"> 4. [] <span style="font-family: Georgia,serif;"> 5. [] <span style="font-family: Georgia,serif;">6. http://www.youtube.com/watch?v=OeCVdLHB5dY <span style="font-family: Georgia,serif;"> 7. [] (BBC) <span style="font-family: Georgia,serif;"> 8. [] <span style="font-family: Georgia,serif;"> 9. @http://www.rspbliverpool.org.uk/fungi.jpg