BIOLOGY FOR MAJORS II: Animal:FFD LAB: Protista
Living organisms are grouped into three general categories called domains: Bacteria, Archaea, and Eukarya. The eukaryotes are currently divided into four kingdoms: Protista, Fungi, Plantae and Animalia. Currently, the classification of the protista is in a state of flux and new evidence seems to indicate that the protists are not monophyletic (share a common ancestor exclusive to protists) and may contain several kingdoms within it. However, we will look at protists as having some unifying characteristics. The Protista (“First of all”) is composed of predominantly single-celled eukaryotic organisms dating back 1.5 billion years. There are more than 200,000 species within this diverse group. Protists are usually unicellular with intracellular specialization where the organelles divide the “labor” within the cell ( however, some are colonial or multicellular). Most Protists reproduce asexually and in some cases, sexually. Protists respond to stimuli with simple reflexes and some have means of locomotion using flagella, cilia or pseudopodia. These organisms can be heterotrophic, saprozoic and/or autotrophic. The current theory of endosymbiosis proposes that these original eukaryotic cells formed when ancestral cells engulfed aerobic bacteria (which became mitochondria) and photosynthetic bacteria (which became chloroplasts). Some members of this group of ancient organisms are the precursors of plants, animals and fungi. The protists we will study are divided into eight monophyletic groups and one polyphyletic group. They eight groups are the Diplomondia/Parabasalida, Euglenozoa, Alveolata, Stramenopila, Rhodophyta, Chlorophyta, Amoebozoa and the Choanoflagellida. The ninth group is loosely organized and includes the Foraminifera/Radiolaria Directions Study the slides (or make wet mounts) of the examples given under each group. Draw and label each organism indicated, including any organelles or structures that help identify the genus or group. Include magnification. Use ¼ page for each drawing. There are a total of 11 organisms to examine but only 8 drawings. Group 1. Diplomondia and Parabasalida: These are primitive eukaryotes that lack mitochondria. They
include the genus Giardia. (No specimens or drawings for this group). Group 2. Euglenozoa. Contains euglenoids and kinetoplastids (single mitochondria) and were among the
earliest free-living eukaryotes to possess mitochondria. Many are photosynthetic, some heterotrophic or parasitic.
Euglena: (live) photosynthetic. View and Draw. Label the chloroplasts and any other structures you can see. Trypanasoma: (slide) parasitic. View and Draw. Label the Trypanasoma and the blood cell.
Group 3. Alveolata : These organisms have a flattened membranous sac beneath outer cell membrane. This group includes ciliates, dinoflagellates (photosynthetic), and the apicomplexans (spore forming parasites). Ciliates. View two, Pick one and Draw:
Blepharisma (live) and Stentor ( live) , Colpidium (Label organelles: nuclear material, cilia), Dinoflagellates: Peridinium (live) (these are the protists responsible for the red tide). View and Draw. Apicomplexa (non-motile spore producer) Plasmodium: Genus can cause malaria; complicated life cycle with stages in liver and in red blood cells; carried by mosquitoes. View and be able to give a simple description of life cycle. (Check your text!) Group 4. Stramenopila: Brown algae (marine: kelp), water molds and diatoms (contain chlorophyll)
Diatoms (slide) View and recognize Group 5. Rhodophyta: Red algae (No examples of this group) Group 6. Chlorophyta: Green algae: a sister group of green plants.
Micrasterias (live) View and Draw. Label any organelles you recognize. Group 7. Amoebozoa: Includes the Amoebas and the slime molds among others. Loosley related group. Amoeba ( slide) View and Draw (label cytoplasm, plasma membrane, vacuole, pseudopod). Chaos (live) View!! Can you find this hidden protist? Group 8. Choanoflagellida: Most like the common ancestor of sponges. A sister group to animals. Includes colonial forms Very rare and very few extant examples. Unfortunately, we have no examples in this group Group 9. Radiolarians and Foraminifera=Marine Protists. Radiolaria (slide). View and Draw and be able to Recognize! Pond Water: Make a wet mount slide. Try and find members of at least two of the protist groups above.