Evolution and Biodiversity Laboratory Systematics and Taxonomy

A. Collecting DataEach student should collect a known volume of water (or sediment, as the case maybe) from your choice of aquatic ecosystem/microhabitat on campus or near your home.Place your sample in a covered, plastic container and label it with:a. your nameb. your lab sectionc. the type of ecosystem (freshwater? Brackish canal? Lake Osceola? Be asspecific as possible)d. type of sample (water column? Water surface? Sediment?)e. Date and time of day the sample was collected.To observe your organsms, draw up one cc (= one milliliter (mL)) of sample. (Again: besure everything is properly labeled so that your samples won’t be misidentified.) Tocount organisms in your sample:1. Place two drops of your sample on a convex microscope slide2. Drop a coverslip onto the liquid3. Place one drop of methyl cellulose at the edge of the coverslip, and allow todiffuse under the coverslip. (This will slow down any rapidly swimmingmicroorganisms)4. STARTING ON LOW POWER, observe your sample under the microscope.5. Begin at one corner of the coverslip, and gradually work your way across anddown, in a zig-zag pattern, until you have observed the entire coverslip field.6. Whenever you find a motile organism (protist or animal), stop and identify it ascompletely as you can by using the Identification Guide following this section.Online sources and the Photo Atlases in lab can also be useful.7. Record your results on the appropriate tally sheets provided.8. Write down the characteristics that allowed you to identify your organism in eachcase.B. Organism Identification GuideSince this is your first introduction to some of the vast diversity of Life, we don'texpect you to be able to identify with any great precision the many organisms we hopeyou will see. However, this guide should help you narrow down the identification of theliving organisms in your sample.Feel free to use online resources for identification. Once you have identified anorganism as a diatom, for example, a Google image search might well yield a possibleidentity for your organism. (Be careful, though. When it comes to protists, it sometimestakes a real expert to tell them apart. We’ll be happy if you learn to tell a flagellate froma ciliate at this stage of the game.)A broad overview of the types of organisms you might encounter can be found at thesehandy sites:http://tinyurl.com/tmhzhttp://www.microscopyu.com/moviegallery/pondscum/If you find something you can't identify, ask your instructor for help.systematics-22