CH. 21 Protists

1. CH. 21 Protists By: Brianna Shields April 27, 2006

2. DO NOW • What

3. GOAL • List the characteristics of protists • List three environments where protists can be found • Identify the unifying features of protists • Distinguish asexual and sexual reproduction of Chlamydomonas • Differentiate two ways multicellular protists reproduce sexually • Identify how amoebas and forams move • Describe the structure of diatoms • Contrast three kinds of algae • Differentiate three different kinds of flagellates • Summarize the general characteristics of a Paramecium • Identify two ways that protists affect human health • Name three human diseases other than malaria, caused by protists • Summarize how malaria is transmitted • Evaluate the methods used to control malaria

4. Protists Diverse Animal, plant and fungus-like Flagella, cilia for locomotion Water environments Some parasitic Can respond to environment Eyespots (light sensitive) Sexual & Asexual Unicellular & multicellular PROTISTS

5. First Eukaryotes Evolved through endosymbiosis PROTISTS

7. Protist Kingdom Protozoa= heterotrophic protists Algae= photosynthetic protists PROTISTS

8. Protist Reproduction Sexual Reproduction in Unicellular Protists Occurs during environmental stress Cell divides into two gametes Gametes from different individuals fuse to form a zygospore (zygote) with thick protective wall Zygospore withstands environmental conditions until they become favorable again Zygospore produces cells that break out of its wall and grow into mature cells PROTISTS

11. Protist Reproduction Sexual Reproduction in Multicellular Protists Alternation of generations Adult sporophyte alga produces spores Spores grow into gametophytes Gametophytes produce gametes that fuse Fused gametes divide through mitosis to form new sporophyte Conjugation Two cells align side by side and pass genetic material between their cell walls PROTISTS

12. Protists: Alternation of Generations

14. Protists: Conjugation

15. Protists: Conjugation

16. Assessment • Describe two ways sexual reproduction can occur in multicellular protists • Summarize why protists are not classified with the other three eukaryotic kingdoms • List three characteristics of protists

17. Amoebas Unicellular, heterotroph Pseudopodia- Flexible, cytoplasmic extensions for moving and eating No cell wall or flagella Freshwater, saltwater and soil Reproduce through fission Some parasitic Ex: Entamoeba histolytica causes Amebic dysentery when transmitted in contaminated food or water PROTISTS

20. Foraminifera Live in sand or attach to rocks Covered by calcium carbonate tests (shells) in a spiral shape Thin streams of cytoplasm extend out of tests for swimming and catching prey Algae live under the tests (symbiosis) Dead foram tests accumulate on ocean floor creating limestone deposits PROTISTS

22. Algae Autotrophic Unicellular and Multicellular PROTISTS

23. Green Algae Mostly freshwater, some marine Mostly unicellular, some multicellular Sexual and asexual stages Part of marine plankton, inhabit damp soil, live with cells of other organisms PROTISTS

24. Red Algae Multicellular Warm ocean waters Absorbing light that penetrates deep waters Used to make agar and carrageenan Complex life cycle (sometimes with alternation of generations) PROTISTS

25. Brown Algae Multicellular Marine environments Kelp grows on coasts- feeds and shelters other organisms Largest organisms on Earth Reproduced by alternation of generations PROTISTS

26. Diatoms Unicellular Producers in oceans and lakes Double silica shells like boxes with lids Diatomaceous Earth Empty shells are mined commerciall Used as an abrasive Sparkle in road paint Natural pest control (sharp edges puncture pests) Glide by secreting chemical through holes in their shells Asexual reproduction- two halves of shell separate, matching half regrows Each generation is smaller and smaller- eventually slips out of its shell to regrow to normal size PROTISTS

28. Flagellates Dinoflagellates Mostly marine Unicellular Autotroph Two flagella Protective cellulose coat encrusted with silica Spin through water like a top Asexual Some produce powerful toxins (ex: red tide) PROTISTS

29. Flagellates Euglenoids Freshwater Two flagella Most photosynthetic, some heterotrophic Pellicle inside cell membrane allows it to change shape Eyespot- detects light Mitotic reproduction PROTISTS

31. Flagellates Kinetoplasts Unicellular, heterotrophs One – one thousand flagella Asexual & Sexual Closely related to Euglenoids Trichonympha live symbiotically in termite gut Trypanosomes cause African Sleeping Sickness in humans PROTISTS

33. Flagellates Ciliates (ex: Paramecium) Many cilia (hairs) Unicellular, heterotrophs Tough, flexible wall allows movement Contractile Vacuole regulates water concentration Asexual: Fission After 700 generations must reproduce sexually through conjugation or they will die PROTISTS

35. Protistan Molds Cellular Slime Molds Ameba-like Lives independently moving through soil, ingesting bacteria Clump with others in a multicellular colony called a slug during environmental stress PROTISTS

36. Protistan Molds Plasmodial Slime Molds Group of organisms that stream along as Plasmodium (mass of cytoplasm resembling oozing slime) During stress, divides into small mounds PROTISTS

37. Protistan Molds Other Molds Water molds White rusts Downy mildews Grow on dead algae and animals in fresh water Many are plant pathogens Phytophthora infestans cauases Irish potato famine of 1845-1847 (400,000 people starved to death) PROTISTS

38. Sporozoans Form spores Parasitic- serious diseases Infect animals- transmitted from host to host Nonmotile Sexual and asexual Large female gamete and small male gamete form a zygote that withstands unfavorable condtions Transmitted by Blood-feeding insects Food, water contaminated with infected animal feces Ex: Malaria PROTISTS

39. Assessment • Fill in a graphic organizer comparing the characteristics of various members of the protist kingdom • Describe a pseudopodium • Identify the role of diatoms in the aquatic food chain • Explain how protistan molds differ from fungi • Euglena is a protozoan not an alga. Is this an accurate statement? Why or why not?

40. Protists and Humans Cause disease in humans and livestock- costly to prevent and treat them Beneficial Protists Live in digestive tracts Cow need them for digesting cellulose Support food chains Produce oxygen Detritivores- recycle nutrients PROTISTS

41. Malaria One of most deadly human diseases 100 million people have it at any given time 3 million die each year Symptoms: chills, fever, sweating, confusion, thirst Death results from: anemia, kidney failure, brain damage Caused by Plasmodium spread by mosquito bites PROTISTS

42. Malaria Life Cycle Mosquito bites and injects thousands of Plasmodium Sporozoites infect liver, rapidly dividing Merozoite cells infect rbc’s and divide rapidly Every 48 hours rbc’s rupture spilling out more merozoites and toxins (causing fever & chills) Some merozoites in blood develop into gametes Mosquito bites infected human- gametes join in mosquito to form zygote Zygote divides to form sporozoites that migrate to mosquito’s salivary glands PROTISTS

44. Malaria Treatment and Prevention Treated with quinine from bark of cinchona tree in South America Reduce mosquito population by spraying insecticides reducing breeding grounds introducing predators to eat mosquito larva PROTISTS

45. Assessment • Describe two ways protists affect human health • Describe three human diseases caused by protists • Diagram the Malaria life cycle and describe how it is transmitted