Chapters 25 and 26 Protists and Fungi

1. Chapters 25 and 26 Protists and Fungi

2. Chapter 25: Protists

3. Kingdom Protista • Kingdom Protistaincludes more than 50,000 kinds of organisms. • They consist of single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom. • Most, but not all are microscopic. • First evolved about 2 billion years ago through the endosymbiosisof small and larger prokaryotes.

4. Characteristics • Overall characteristics vary widely: • Some are unicellular. Ex: Amoeba • Some form colonies. Ex: Volvox • Some are multicellular. Ex: Brown Algae • Many are autotrophs; making food through photosynthesis • Some are heterotrophs; either eating other protists or by decomposing and absorbing nutrients as fungi do. • Variety of ways to move: flagella, cilia, or pseudopods

5. Reproduction • Most reproduce asexuallyby binary fissionor multiple fission • Binary fission: one cell divides into two identical cells • Multiple fission: one cell divides into more than two cells • Some reproduce sexuallyby conjugation • Two cells join and exchange genetic material • Then each divides to produce four new offspring.

6. Groups of Protists • Three main groups of protists are generally recognized: Fungus-like Animal-like Plant-like

7. Animal-like Protists • Often called Protozoans • Unicellular(one-celled) • Cannot make food: eat bacteria, algae, and other protozoans • Four phyla based on movement: Protozoa, Ciliophora, Sarcomastigophora, and Apicomplexa

8. Phylum Protozoa • Move and feed by using finger-like projections called pseudopods • Most live in freshwater. • All change shape as they move. • Example: Amoeba Amoeba feeding on a bacterial cell.

9. Phylum Ciliophora • Move by tiny hair-like structures called cilia. • Most live in freshwater. • Slipper-shaped. Surrounded by a membrane-like structure called a pellicle. • All have two nuclei: macronucleus(controls most cell activities) and micronucleus(controls reproduction) • Ex: Paramecium Contractile vacuole controls water movement in and out. Feed through oral groove

10. Phylum Sarcomastigophora • Move by using a whip-like tail called a flagella. • Some have oneflagella, others have many. • Live in fresh or salt wateror as disease-causing parasitesin animals. • Example: Trypanosome flagellate causes African Sleeping Sickness. It is transmitted by the bite of the tsetse fly. Trypanosome flagellate Tsetse fly

11. Phylum Apicomplexa • Also known as sporozoans. • Animal-like protists that live as parasites. • Can not move on their own. • Most feed on the blood of human or animal hosts. • Malariais caused by a sporozoan called Plasmodium. It is transmitted by the bite of the Anopheles mosquito. The plasmodium produce poisons that cause fever and chills. Sporozoans Anopheles mosquito

12. Plant-like Protists • Also known as algae. • Can be single-celled, many-celled or live in colonies. • All contain chlorophylland can make food. • Some contain other colored pigments as well. • Classified into seven phyla based on the pigments they contain and the number of cells

13. Characteristics of Algae • Important part of the microscopic plants and animals found floating near the surface of water known as plankton. • Plant-like plankton that makes its own food is called phytoplankton. • It is responsible for producing about 90% of the earth’s oxygen as well as being an important part of the food chain.

14. Phylum Chlorophyta • Green Algae • Ancestors of green plants. • Contain chlorophyll a and b and store food as starch. • Most species are freshwater and can be single-celled, live in colonies, or in filamentous, multicellular forms • Salt-water species are many celled. Volvox Ulva Spirogyra

15. Phylum Phaeophyta • Brown Algae • Contains chlorophylls a and c • Saltwater algae known as seaweedor kelp. • Common along rock coast lines in cold water. • Grow very large(100m) • Many have small, light-colored structures called air bladdersto keep them floating near the surface.

16. Phylum Rhodophyta • Red Algae • Contain chlorophyll a and phycobilinsthat allow them to absorb wavelengths of light from deep water. • Also called seaweed. • Found in deep ocean water. • Used to make agar, and in pudding, ice cream, cheese, salad dressing and marshmallows

17. Phylum Bacillariophyta • Diatoms • Yellow or brown in color. Come in many shapes and patterns. • Covered by shellsthat are made of a glass-like substance known as silica. These shells are used in toothpaste, silver polish, detergents, insulation and road paint.

18. Phylum Dinoflagellata • Fire algae • Many are redin color. Found in salt water. • Most have two flagella and spinas they move • Responsible for red-tides (Ocean turns red because of a population explosion of fire algae. The algae produce poisons that can kill fish and people).

19. Phylum Chrysophyta • Golden Algae • Most live in freshwater • Form highly resistant cysts to survive in frozen or dried up lake beds • Store energy as oil • Probably play a role in formation of petroleum deposits

20. Phylum Euglenophyta • Euglenoids • Have both plant and animal like characteristics. • Can make food when light is present. Can eat food when it is not. • Have an eyespotthat responds to light (swims toward it). • Move by using a flagella

21. Fungus-like Protists • Fungus-like protists —also known as slime molds and water molds. • They have features of both protists and fungi. • Four phyla: Phylum Chytridiomycota: Water mold Phylum Oomycota: Water mold Phylum Dictyostelida: Cellular Slime Mold Phylum Myxomycota: Plasmodial Slime Mold

22. Slime Molds • Slime molds —two stage life cycle: • Reproductive stage: resembles a fungus • Feeding stage: resembles an amoeba (protist) • During the feeding stage, slime molds appear in one of two forms: plasmodial slime molds(consisting of a large mass of cytoplasm with many nuclei); and cellular slime molds(consisting of individual amoebalike cells). Plasmodial slime mold Cellular slime mold

23. Water Molds • Most are parasiticand grow as long filaments on the host, eventually harming them.

24. Chapter 26: Fungi

25. Kingdom Fungi • Kingdom Fungi — consists of many-celled organisms that can not make food and can not move around. • Do not have chlorophyll. • Most get food by decomposing and absorbing dead organic matter (saprophytes). • Some get food from living host organisms (parasites). • Fungi do not have roots, leaves or tissue layers. • Store energy in the form of glycogen.

26. Fungus Structure • The body of a fungus is made of a mass of thread-like tubes known as hyphae. • Hyphaeusually grow underground and may join to form above ground reproductive structures like mushroom caps. • Cell walls made of chitin. • Grow best in warm, moist places. • Reproduce by forming spores.

27. Phylum Zygomycota • Zygote Fungi: spores are produced in round spore cases called sporangia. • Example: Bread mold

28. Phylum Basidiomycota • Club Fungi: spores are produced in a club-shaped structure called a basidium(pl. basidia) • Examples: mushrooms and rusts

29. Phylum Ascomycota • Sac Fungi: spores are produced in a sac-like structure called an ascus(pl. asci) • Examples: yeasts, molds, morels and truffles

30. Phylum Deuteromycota • Imperfect Fungi: reproductive stage has never been observed. • Examples: ringworm fungus, athletes foot fungus and Penicillium (used to make Penicillin). Ringworm infection Athletes foot infection

31. Micorrhizae • A micorrhizais a symbiotic structure formed by a fungus and plant roots. • More than 80% of vascular plants contain such fungi on their roots. • The fungus absorbs and concentratesnitrogen, phosphate and other ions for the plant’s use • The plant supplies the fungus with sugarfrom photosynthesis The micorrhizae appear as nodules on the plant’s roots

32. Lichens • A lichenis actually two organisms living together: a fungus and an algae (or cyanobacteria) • Both benefit • Algae makes food for fungus. • Fungus improves living conditions for algae by secreting acids that begin to break rock into soil. • Live on rocks, soil, branches or tree trunks. • Considered a pioneer species