Protist is a catch-all term that usually refers to single-celled, eukaryotic organisms. Protists can be animal-like, fungal-like or plant-like in terms of the organelles they contain. The animal-like protists have traditionally been called “protozoans.” They are heterotrophic and usually have structures for motility. Plant-like protists are autotrophic and capable of photosynthesis. Many of them are floaters, with no structures for motility.

Protists are among the largest of all eukaryotic cells. They often have specialized organelles that are not found in the cells of multicellular organisms. These organelles combine to accomplish the basic functions that we associate with entire organ systems of plants and animals. For example, there are organelles in some freshwater protists that maintain osmotic equilibrium by pumping excess fluid out of the cell—a function performed by the urinary system of most animals. There are also protists that do not fit neatly into plant-like or animal-like categories.

1. Study the following video of an ambiguous protist. (The video has no sound.) Then write a short description indicating why you think the protist is more animal-like or more plant-like. (Base your answer on observations of the protist.)

   Ambiguous Protist. Introductory Biology: Ecology, Evolution, and Biodiversity. Retrieved March 27, 2018, from http://projects.ncsu.edu/project/bio181de/Lab/protists-fungi/euglena.html

2. View the following video of two animal-like protists, Stentor and Voticella (audio included), and then answer the questions listed below:

   Stentor and Vorticella. Introductory Biology: Ecology, Evolution, and Biodiversity.Retrieved March 27, 2018, from http://projects.ncsu.edu/project/bio181de/Lab/protists-fungi/protozoans.html

   1. Describe the ways in which Stentor and Vorticella feed; what structures are involved in feeding?
   2. Name, and briefly describe, one internal organelle in each protist.
3. Research one additional protist. Insert an image of your chosen protist into your word document (it should be no larger than 2.5-by-3 inches). Describe its beneficial or harmful effects on humans.

Assignment Expectations

Organize this essay assignment using subtitles that summarize the topic from each question above. For example, use descriptive subtitles such as Ambiguous Protist, etc.

Your essay should be approximately 1½–2 pages. Answer each question under the subtitle using complete sentences that relate back to the question. Be sure to use APA formatting throughout your essay, and use 1-inch margins, 12-point type and double spacing. Include a title page, an introduction, answers to the questions with subtitles, and a concluding paragraph. Remember to include in-text citations within the body of the essay referencing your resources (e.g., Murray, 2014). Also, be sure to include a reference section at the end of your assignment listing all required readings and any additional resources you used to complete your essay. A helpful guide to writing a quality essay can be found in Writing Tips. The Student Guide to Writing a High-Quality Academic Paper also provides links to example essays written within APA format.

Direct quotes should be limited and must be designated by quotation marks. Paraphrased ideas must give credit to the original author, for example: (Murray, 2014). Direct copying from “homework help” websites will not receive credit. Once you have completed your assignment within a Word document, please upload your final version to the Case 3 Dropbox. Please also note your Turnitin originality score and make revisions as needed. Please contact your instructor with any questions.