1. Protists

2. Protists Were once grouped in a single kingdom – Protista Were once grouped in a single kingdom – Protista –Now make up many kingdoms Includes eukaryotes that do not fit into fungi, plants, or animal kingdoms Includes eukaryotes that do not fit into fungi, plants, or animal kingdoms Very diverse group Very diverse group –Vary in structure and function more than any other group –All commonalities have exceptions

3. Similarities Remember…even these have exceptions Remember…even these have exceptions Most are unicellular Most are unicellular –May colonize or be multicellular Most use aerobic metabolism Most use aerobic metabolism Most have mitochondria Most have mitochondria –Evolved through endosymbiosis – the engulfing and symbiotic relationships of prokaryotes

4. Endosymbiotic Theory Serial endosymbiosis – proposes mitochondria and chloroplasts were formerly small prokaryotes living within larger cells Serial endosymbiosis – proposes mitochondria and chloroplasts were formerly small prokaryotes living within larger cells Evidence includes: Evidence includes: –Modern endosymbiotic relationships –Similarities between these organelles and bacteria Size, inner membranes, enzymes, replication, genome, ribosomes Size, inner membranes, enzymes, replication, genome, ribosomes

5. Other characteristics Diverse nutrition Diverse nutrition –May be photoautotrophs, heterotrophs, or mixotrophs (combine photosynthesis and heterotrophic nutrition) Based on this, they can be divided into three categories: Based on this, they can be divided into three categories: –Animal like protists – Protozoa (ingestive) –Fungus like protists – (absorptive) –Plant like protists – Algae (photosynthetic)

6. Motility Most are motile, with flagella or cilia at some point during life cycle Most are motile, with flagella or cilia at some point during life cycle –Both are extensions of cytoplasm –Cilia are shorter and more numerous Some may move by pseudopods or “false feet” Some may move by pseudopods or “false feet”

7. Life Cycles Highly varied Highly varied –Mitosis occurs in almost all protists –Some are exclusively asexual –Others reproduce sexually through meiosis and syngamy (union of gametes) May vary in timing May vary in timing –Some form resistant cells called cysts during harsh conditions

8. Habitats Most are aquatic or in moist environments Most are aquatic or in moist environments Many are aquatic bottom dwellers that attach themselves to rocks or creep through sand and silt Many are aquatic bottom dwellers that attach themselves to rocks or creep through sand and silt Major component of plankton (microscopic floaters) Major component of plankton (microscopic floaters) –Phytoplankton – photosynthetic; Zooplankton – animal like –Major part of marine and freshwater food webs Many are symbionts – mostly parasites that inhabit tissues, cells, or fluids of a host Many are symbionts – mostly parasites that inhabit tissues, cells, or fluids of a host

9. 1. 2. 3. 4. 5. 6.

10. Major Evolutionary Branches 1. Autotrophs vs. heterotrophs and decomposers 2. Flagella vs. no flagella 3. Presence of crystal rods in flagella vs. no crystal rods 4. Symbiosis with fungi (lichens) vs. independent survival 5. Shallow water vs. live on land 6. Decomposer vs. heterotrophic consumer

11. Protists to Know –Zooflagellates (Trichomonas vaginalis) –Amoeba –Euglena –Dinoflagellates –Ciliates (Paramecium) –Diatoms –Algae: golden, brown, red and green –Oomycetes: water molds –Slime molds –Giardia intestinalis –Trypanosoma sp. –Plasmodium

12. Fungi

13. General Characteristics Eukaryotes Eukaryotes Multicellular (except yeasts) Multicellular (except yeasts) Cell walls made of chitin Cell walls made of chitin –Nitrogen-containing polysaccharide –Also found in exoskeletons of insects

14. Nutrition Heterotrophs Heterotrophs Obtain nutrients by absorption Obtain nutrients by absorption –Secrete hydrolytic enzymes to digest food outside bodies and then absorb the simpler compounds Called saprobes Called saprobes –May be decomposers, parasites, or mutualistic symbionts

15. Structure Bodies constructed of tiny filaments called hyphae Bodies constructed of tiny filaments called hyphae –Entwined to form a mass called the mycelium Increase surface area for absorption Increase surface area for absorption –Most are divided into cells by cross walls called septa Except for Coenocytic fungi – have continuous cytoplasmic mass Except for Coenocytic fungi – have continuous cytoplasmic mass –May have an above ground reproductive structure – fruiting body

16. Hyphae and Mycelium

17. Reproduction Release spores that are produced either sexually or asexually Release spores that are produced either sexually or asexually –Spores germinate to produce mycelia Two hyphae may fuse and have genetically different nuclei – heterokaryon Two hyphae may fuse and have genetically different nuclei – heterokaryon Some sexual cycles occur in two stages: Some sexual cycles occur in two stages: –Plasmogamy – fusion of cytoplasm when mycelia come together –Karyogamy – fusion of haploid nuclei

19. Fungi Diversity Placed into different phyla based on types of structures produced during sexual reproduction stages Placed into different phyla based on types of structures produced during sexual reproduction stages Phylum Chytridiomycota (chytrids) Phylum Chytridiomycota (chytrids) –Mainly aquatic –Form uniflagellated spores (zoospores) –Possibly most primitive fungi

20. Phlyum Zygomycota (zygomycetes) Include fast-growing molds, parasites, and symbionts Include fast-growing molds, parasites, and symbionts Produce resistant structure called zygosporangium Produce resistant structure called zygosporangium –Multinucleate structure –Resistant to freezing and drying –Metabolically inactive

22. Phylum Ascomycota (sac fungi) Include yeasts, cup fungi, morels and truffles, and plant pathogens Include yeasts, cup fungi, morels and truffles, and plant pathogens Produce sexual spores in sac-like structures called asci Produce sexual spores in sac-like structures called asci –Sexual stages occur in fruiting bodies called ascocarps –Includes Sordaria

23. Cont’d

24. Phylum Basidiomycota (club fungi) Includes mushrooms, shelf fungi, puffballs Includes mushrooms, shelf fungi, puffballs Name derived from basidium “little pedestal”, a diploid stage in the life cycle Name derived from basidium “little pedestal”, a diploid stage in the life cycle Periodically, they produce elaborate fruiting bodies called basidiocarps (typical mushroom look) Periodically, they produce elaborate fruiting bodies called basidiocarps (typical mushroom look) –Source of sexual spores

26. Other Groupings Molds – rapidly growing, asexual Molds – rapidly growing, asexual Yeasts – Unicellular and usually live in liquids Yeasts – Unicellular and usually live in liquids Lichens – mutualistic associations of algae and fungi Lichens – mutualistic associations of algae and fungi –Food for fungus, environment for algae Mycorrhizae – mutualistic associations of fungi and plant roots Mycorrhizae – mutualistic associations of fungi and plant roots –Increases absorptive surface of plant roots and the two exchange minerals and organic compounds

28. Ecological Impact Decomposers Decomposers –Keep nutrients available for other organisms –Can ruin fruits and wood Parasites (about 30%) and Pathogens Parasites (about 30%) and Pathogens –Can eliminate plant species or reduce numbers; agricultural pests –In animals: ringworms, athlete’s foot, Candida yeast infections –Mycosis – fungal infection Food industry – baking and wine making Food industry – baking and wine making Antibiotic production Antibiotic production