Protista Zach Fischenich

Protists Protists are bacterium or related organisms –They are organisms belonging to the kingdom that includes protozoans, bacteria, and single- celled algae and fungi. Kingdom: Protista –Ex. - Dinoflagellates, euglenoids, foraminiferans, and plasmodial slime molds

Protists Cont. Protists do not have much in common besides a relatively simple organization –They are either unicellular or multicellular The simple cellular organization distinguishes the protists from other eukaryotes, such as fungi, animals, and plants

Protists History The term protista was first used by Ernst Haeckel in 1866 Traditionally, protists were subdivided into several groups based on similarities to the “higher” kingdoms –The one-celled animal-like protozoa, the plant-like protophyta (mostly one-celled agae), and the fungus-like slime molds and water molds

Protist Cont. Protists live in almost any environment that contains liquid water Most protists, such as algae, are photosynthetic and are vital primary producers in ecosystems, particularly in the ocean as part of the plankton Other protists, such as the Kinetoplastids and Apicomplexa are responsible for a range of serious human diseases, such as malaria and sleeping sickness

Dinoflagellates Dinoflagellates are microscopic, (usually) unicellular, flagellated, and often photosynthetic protists –They are commonly regarded as “algae” (Division Dinoflagellata).

Dinoflagellates Cont. Most are marine plankton, but they are common in fresh water habitats as well About half of all dinoflagellates are photosynthetic –These make up the largest group of algae aside from diatoms

Dinoflagellates Facts Red Tide –Happens when dinoflagellates are in concentrations of more than one million cells per milliliter Some species produce neurotoxins, which in such quantities kill fish –Called red tide for the color the bloom imparts to the water

Dinoflagellate Pics

Euglenoids They are unicellular organisms –Their classification can be debated either way between plants and animals They exhibit both plant and animal characteristics They are not related to any algae –Still included in algae study –Also included in studies of single-celled animals known as protozoa

Euglenoids Cont. Pigments: Green –A few are colorless Pigmentation is dependent on whether they are exposed to light or not Habitat: Marine and fresh water Body types: Single cell

Euglenoid Facts Don’t have cell wall –Bound by a flexible pellicle Pellicle- A thin film or membrane Mobility: movement created by one- long tinsel flagella Value: A food source for fish and other aquatic animals

Euglenoid Pics

Foraminiferans Foraminiferan are large, shelled ameboid protozoans belonging to the phylum Sarcodina Most foraminiferan shells are calcareous, but some are siliceous, and others are built of sand grains Initially, the shell contains a single chamber, and new chambers are added in a characteristic linear, spiral, or concentric series as the organism grows

Foraminiferans Cont. Some shells reach several inches in diameter, but most species are less than a millimeter in diameter They form a net in which they trap plankton organisms –The net may cover an are 10 times the diameter of the shell

Foraminiferans Cont. A few foraminiferans live in freshwater or brackish water, but the majority are marine They are found in all seas at all depths and are extremely abundant They may be red, brown, or white in color About 30 pelagic species live in the sea

Foraminiferan Pics

Plasmodial Slime Molds Plasmodial Slime Molds are basically enormous single cells with thousands of nuclei They are formed when individual flagellated cells swarm together and fuse –The result is one large bag of cytoplasm with many diploid nuclei

Plasmodial Slime Molds Cont. These “giant cells” have been quite useful in studies of cytoplasmic streaming (the movement of cell contents) because it is possible to see this happening even under fairly low magnification The large size of the slime mold “cell” makes them easier to manipulate than most cells

Plasmodial Slime Mold Pics

Question 1 What are most protists? –A. Photosynthetic –B. Unicellular –C. Complex Organisms –D. Multi-cellular

Question 2 Dinoflagellates are…. –A. Fungi –B. Bacteria –C. Algae –D. Protozoans

Question 3 Where do euglenoids live? –A. Dessert –B. Marine & Fresh Water –C. In the soil –D. In mammals

Question 4 About how many pelagic species of foraminiferan live in the sea? –A. 200 –B. 30 –C. 50 –D. 5

Question 5 Plasmodial Slime Mold Cells have been quite useful in what? –A. Cancer Research –B. Creating Vaccines –C. Cytoplasmic Streaming –D. Nothing. They are useless