PROTISTS Chapter 25 Biology II
Vocabulary- Protists (44 words) 1. Protist 2. binary fission 3. conjugation 4. Multiple fission 5. pseudopodium 6. test 7. Amoeboid movement 8. cilium 9. Pellicle 10. oral groove 11. mouth pore 12. Gullet 13. anal poore 14. macronucleus 15. Contractile vacuole 16. micronucleus 17. Flagellum 18. alga 19. gametangium 20. Phytoplankton 21. thallus 22. shell 23. Accessory pigment 24. diatom 25. Bioluminescence 26. red tide 27. Euglenoid 28. fruiting body 29. water mold 30. Plasmodial slime mold 31. algal bloom 32. Cellular slime mold 33. chemotaxis 34. Alginate 35. carrageenan 36. agar 37. Diatomaceous earth 38. malaria 39. sporozoite 40. Merozoite 41. gametocyte 42. giardiasis 43. Cryptosporidiosis 44. trichomoniasis
A. Characteristics of Protists 1. A Diverse Group of Eukaryotes a. Protists: an organism that is classified as a member of the kingdom Protista; generally, a single celled or simple multicellular eukaryote that cannot be readily classified as either plant, animal, or fungus b. Most are single celled, but some several meters long (multicellular) c. Most diverse group of all eukaryotes (body plans, movement) d. Made of eukaryotic cells, containing nucleus and other organelles
e. First protists arose from prokaryotic cells 2. Classification a. Protists are classified by the characteristics that resemble those of fungi, plants, and animals b. Such great diversity has caused scientists to believe that Protists should be divided into many kingdoms
3. Characteristics a. Unicellular and Multicellular 1. Most are unicellular, but some form large multicellular bodies
b. Nutrition 1. Obtain nutrients in a number of ways 2. Many protists are autotrophs (make their own food)- use chloroplasts just like plants 3. Some protists are heterotrophs (get food by eating other organisms)- some eat like animals, while others secrete digestive enzymes and absorb the food like fungi c. Motility 1. Most protists are able to move at some time during their life cycle 2. Move by flagella (whip-like tail), cilia (hair-like structures), or pseudopodium (blob-like)
d. Reproduction 1. Many protists reproduce asexually 2. Binary fission: asexual reproduction where a single cell splits into two cells 3. Multiple fission: a form of cell division that produces more than two offspring from one cell 4. Conjugation: two individuals join and exchange genetic material stored in a small second nucleus, then the cell divides into four offspring a. Offspring genetically different- sexual reproduction b. Some protists do this during stressful environmental conditions
B. Animal-Like Protists- not related to animals, but obtain food in an animal-like way 1. Phylum Protozoa a. Most are heterotrophs b. Move independently without cilia or flagella c. Pseudopodia: large, rounded cytoplasmic extensions that function in movement and feeding d. Amoeboid movement: the act of moving using the pseudopods extending and retracting e. Test: a protective shell that covers some Protozoa f. Example: amoebas
2. Phylum Ciliophora a. All members have cilia which allows them to move b. Cilia: short, hair-like cytoplasmic projections that line the cell membrane c. Have the most elaborate organelles of any protist (ex. Oral groove, mouth pore, gullet, anal pore) d. Reproduce sexually and asexually e. Example: Paramecia
3. Phylum Sarcomastigophora a. Each member has one or more flagella b. Flagella: long, whip-like structures that are made up of microtubules and used for movement c. Some are free living, while some are parasites d. Examples: Trypanosomes
4. Phylum Apicomplexa a. Adult forms have no means of locomotion b. All are animal parasites c. Reproduce sexually and asexually d. Example: Plasmodium
C. Plantlike and Fungus Protists 1. Characteristics of Algae a. Most plantlike protists are known as algae b. Autotrophic protists (make their own food) c. Have chlorophyll and at some point in their life cycle has a flagella d. 4 basic body forms: 1. unicellular algae: one-celled (phytoplankton) 2. colonial algae: group of individual cells (Volvox) 3. filamentous algae: multicellular rods joined end to end (spirogyra) 4. multicellular algae: large and complex (kelpseaweed)
2. Phylum Chlorophyta (Green Algae) a. Can range from unicellular and colonies to filamentous and multicellular form b. Contains chlorophyll and carotenoids like plants c. Cell walls made of cellulose d. Most are aquatic, some live symbiotically with fungi (lichen) or with invertebrates (coral)
3. Phylum Phaeophyta (Brown Algae) a. Contains chlorophyll and fucoxantin (brown color) b. Mostly marine organisms (includes kelp and seaweed) c. Contain the largest known alga (giant kelp)
4. Phylum Rhodophyta (Red Algae) a. Contain chlorophyll and phycobilins (absorb lightwaves that penetrate deep into the water) b. Found in deep parts of the water, while some live in fresh water or on land
5. Phylum Bacillariophyta (Diatoms) a. Unicellular protists called diatoms b. Have cells walls called shells that fit together in two pieces c. Abundant component of phytoplankton and major producers 6. Phylum Dinoflagellata (Dinoflagellates) a. Unicellular containing two flagella b. Most photosynthetic autotrophs c. Some produce bioluminescence (light) d. Responsible for red tide- toxins kill large number of fish
7. Phlyum Chrysophyta (Golden Algae) a. Most live in fresh water and form a highly resistant cyst that allows them to survive under frozen surfaces and dry lake beds during the summer 8. Phylum Euglenophyta (Euglenoids) a. Flagellated unicellular algae called euglenoids b. Euglenoids are both plant and animal-like c. Contain chlorophyll, but move and lack a cell wall
9. Funguslike Protist a. Phylum Myxomycota (Plasmodial Slime Molds) 1. During feeding stage of life cycle, creeps along forest floor by cytoplasmic streaming 2. When food and water are scare, begins to reproduce producing spores, which are resistant to harsh conditions
b. Phlyum Dictyostelida (Cellular Slime Mold) 1. Move about the ground or swimming in fresh water like an amoeba 2. When food or water become scarce, release a chemical to attract other nearby cells to form a dense structure called pseudoplasmodium (eventually settles and reproduces starting cycle over again)
c. Phylum Oomycota (Water Molds) 1. Many parasites that reproduce sexually and asexually d. Phylum Chrytridiomycota (Water Molds) 1. Aquatic protists with posterior flagellum 2. Share many characteristics with fungi
D. Protists and Humans 1. Protists in the Environment a. Photosynthetic protists are bases of many food chains and produce large quantities of oxygen b. Play important role in carbon cycle and form many symbiotic relationships (coral, lichen) c. Algal blooms: a vast increase in the concentration of diatoms and other photosynthetic protists 1. Dinoflagellate bloom causes red tide
2. Protists in Research- have helped study cell movement and chemotaxis 3. Protists in Industry a. Protists are used as food (seaweeds), cosmetics, medicines, medical research, detergents, and many more
4. Protists and Health a. Malaria 1. Apicomplexans called Plasmodium cause this disease 2. Kills 3 million people a year- severe chills, headache, fever, and fatigue b. Giardiasis 1. severe diarrhea and intestinal cramps 2. get from drinking contaminated water
c. Cryptosporidiosis- characterized by diarrhea, not fatal, but dangerous with people having immune problems d. Trichomoniasis- STD