Lab 3 Protists and Fungi

September 13, 2011

Taxonomy

We use a number of level to classify organisms. The coarsest level oforganization is the domain. Organisms may be classified as Archea, Bacteria,or Eukarya. In this class we will examine the Eukarya or organisms with atrue nucleus. The other levels of organization are listed below from coarsestto finest.

Domain Kingdom Phylum Class Order Family Genus SpeciesProtists

Protists are a group of organisms that consist of all eukaryotic organismsthat are not plants, animals, or fungi. At one time this was considered to bea kingdom, however it has now been broken up into many kingdoms. It is

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not a monophyletic group.

You will need to be familiar with a few terms related to movement andobtaining food. Terms relating to how organisms obtain their food are listedbelow:

autotroph: makes ones own food from sun or abiotic chemical energy heterotroph: obtains food from other organisms mixotroph: able to obtain food through autotrophy or heterotrophyMany single celled organisms use one of the following structures.

flagella: whip like structures cilia: small hair like structures pseudopodia: false foot, move by flowing (pseudopod singular)Eukaryotes have obtained organelles through the process of endosymbio-

sis. Mitochondria and chloroplasts were obtained by primary endosymbiosis.Primary endosymbiosis is the forming of a symbiotic relationship with aprokaryote living inside a eukaryotic cell. Secondary endosymbiosis occurswhen an eukaryote forms an symbiotic relationship with a eukaryotic organ-ism inside its cell.

You should be familiar with the following terms relating to reproduction:

Asexual reproduction: reproduction requiring only one organism to reproduce, reproduc-

tion without sex

Sexual reproduction: is reproduction that uses the fusion of nuclei from different cells

cells to reproduce. In short they use sex to reproduce. This usuallyinvolves two organisms, but occasionally will involve the combi-nation of reproductive cells from the same organism.

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When they are two different mating types we refer to them as +and - if they are the same size. If the gametes or sex cells aredifferent sized than we refer to them as male and female. Thefemale is the large gamete and the male is the small gamete.

mitosis: Process of cell division that produces 2 diploid daughter cells

meiosis: Process of cell division that produces 4 haploid daughter cells

You should be familiar with the 5 main groups of organisms listed below.

Archaeplatida

This group consists of photoautotrophs including red and green algae andplants. This group are important primary producers.

Red algae Red algae have red colored pigments which mask the green of their

chloroplasts. These include many of the algae that we eat such asin sushi.

Green algae Consist of two groups Chloropytes and Charophyceans.

Charophyceans are the closest relatives to land plants. Greenalgae are not a monophyletic group because Charophyceans aremore closely related to land plants than Chlorophytes

Land Plants will be discussed in next weeks lab. This is one of twogroups that shows a true alternation of generations. That is they havemulticellular haploid and diploid stages.

Chromalveolata

This group results from a secondary Endosymbiosis with a red algae.

Dinoflagellates have 2 flagella. These are the organisms that cause redtides.

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Apicomplexans are an important group because they contain the par-asite Plasmodium (malaria)

Ciliates have cilia which they use for locomotion. Paramecium is anexample of this taxa.

Oomycetes, were once classified as fungi. These contain importantplant pathogens such as potato late blight and sudden oak death.

Diatoms are responsible for diatomous earth. They are important pri-mary producers in our oceans. And are also important for carbonsequestraition because they decompose slowly.

Golden Algae Brown Algae is a group of multicellular algae. They provide important

marine habitat. They are one of two taxonomic groups to have a truealternation of generations.

Excavata

This group contains many important human paracites.

Diplomanads include the gastrointestinal parasite Giardia. Parabasalids include the termite symbionts that allow them to digest

cellulose.

Euglenozoans include the parasites Leishmania

and Trypanosoma brucei: african sleeping sickness.

Rhizaria

are amoeba like with root looking pseudopodia. They include:

Chlorarachniophytes Forams

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Radiolarians

Unikonata

Unikonata includes the following groups.

Amoezoans Slime molds

Gymnamoebas

Entamoebas, which include the causes of amebic dysentery

Opisthokonts Nucleariids

Fungi

Choanoflagellates

animals

Fungi

Fungi are heterotrophs that have cell walls made of chitin. Chitin is thesame material that makes up the exoskeletons of insects. They may repro-duce sexually, asexually or both sexually and asexually.

Hyphae: tiny filaments which make up the bodies of fungi.

Mycelium: an interwoven mass of hyphae

Mycorrhizae: (fungus roots) mutualistic relationships between fungi andplant roots

Ectomycorrhizae: form sheaths of hyphae over the surface of the root toexchange nutrients with the plant.

Arbuscular mycorrhizae: extend hyphae through the cell wall to exchangenutrients with the plant.

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Figure 1: fungal lifecycle

Heterokaryon or heterokaryotic stage: cells contain 2 or more haploid nu-clei

Dikaryotic: cell containing 2 nuclei

fungal lifecycleImportant terms for fungal lifecycle

Plasmogamy: fusion of cytopalsm Karyogamy: fusion of nucleausFungi

Chytrids

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Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes

There are 5 phyla of fungi.Basidiomycetes

Distinguished by their fruiting body called a Basidiocarp. These arethe most recognizable fungi. They include important decomposers, plantpathogens, and edible mushrooms. Some examples are:

Portabella and common white mushrooms club fungi fairy rings and puffballs wheat rust

Ascomycetes

Ascomycetes are the sac like fungi. They have a sac like fruiting bodycalled an ascocarp. They include edible mushrooms, plant pathogens, my-chorhizae and human pathogens. Some examples are:

morells and truffels Claviceps purpurea, ergot yeast Some fungi in the genus Trichophyton cause athletes foot. Penicillium from which penicillin is obtained

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Zygomycetes

This phylum of fungi is named for its heterokaryotic stage the Zygospo-rangium which can survive harsh conditions for long periods of time. Anexample is black bread mold.

Glomeromycites

This phylum was once grouped in with the zygomycetes, but it has nowbeen placed in its own monophyletic group based on genetic information.Most fungi in this taxon are arbuscular mycorrhizae.

Cytrids

This group is most likely paraphyletic, consisting of more than one cladeor monophyletic group. This group is unique in that they have flagellatedspores called zoospores. Some live in the digestive tracts of sheep and cattleand help break down plant matter.

For your quiz:

know how to calculate your microscope magnification: ocular lens mag-nification * objective lens magnification

know the definitions given know the general fungal lifecycle be able to list a protist and a fungus that is harmful to people and one

that is beneficial to people and be able to list what group it belongsto. You must be more specific than Fungi or protist.

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