Kingdom Protista

1. Kingdom Protista Chapter 19

2. What is a protist? • Protists may be: • unicellular or multicellular. • microscopic to very large. • heterotrophic or autotrophic. • beneficial, parasitic, or innocuous. • Are all eukaryotes. • There are 3 major categories of protists: • animal-like protists • plant-like protists • fungus-like protists

3. Protozoa: The animal-like protists • unicellular • heterotrophic • reproduction • usually asexually • sometimes sexually • 4 main groups • amoebas • flagellates • ciliates • sporozoans

4. Phylum Rhizopoda: The Amoebas • Are shapeless protists • Move and feed with the aid of cytoplasm filled projections called pseudopodia (false foot) • Live in mostly marine environments, but are also found in freshwater environments

5. Phylum Zoomastigina: The Flagellates • Protozoans with one or more flagella • Some are parasites • ex. Trypanosoma brucei (African sleeping sickness) • Some are beneficial • ex. Trichonympha spp. (termites)

6. Phylum Ciliophora: The Ciliates • Are covered with cilia that aid in locomotion • Live in aquatic environments • ex. Paramecium

7. Phylum Sporozoa: The Sporozoans • Most produce spores • spore is a reproductive cell • forms without fertilization • All are internalparasites • Have complex life cycles • Ex. Plasmodium, which causes malaria

8. Algae: The plant-like protists • Are photosynthetic autotrophs • Are unicellular or multi-cellular • Unicellular (also know as phytoplankton) • euglena • diatoms • dinoflagellates • Multicellular: • red algae • brown algae • green algae

9. Phylum Euglenophyta: The Euglenoids • Are unicellular • Are both autotrophic and heterotrophic • Have a flagella • Photosynthesize when light is favorable • Ingest food when light is not favorable • Do NOT have a cell wall, but have a flexible • pellicle made of protein

10. Phylum Bacillariophyta: The Diatoms • Are unicellular • Photosynthetic autotrophs • Have shells composed of silica (SiO2) • Aquatic environments

11. Phylum Dinoflagellata: Dinoflagellates • Have cell walls composed of cellulose • Have two flagella located in grooves at right angles to each other • Mostly marine • Some live in symbiotic relationships • ex. coral • Some are toxic • ex. Gonyaulux catanella (red tide)

12. The Multicellular Algae: 3 Phyla • Rhodaphyta: red algae • Live in deep waters • Phaeophyta: brown algae • Include kelp • Have air bladders to float • Chlorophyta: green algae • Most diverse (>7000 spp.) • Ex. Volvox & Spirogyra

13. The Fungus-like Protists • Are all heterotrophicdecomposers • Two main groups with 3 phyla • The slime molds • Myxomycota • Acrasiomycota • Water molds and downy mildews • Oomycota

14. Phylum Myxomycota • Consist of the plasmodial slime molds • Plasmodium: • mass of cytoplasm that contains many diploid nuclei but contain no cell walls or membranes • Move at ~2.5cm/hr • Can reach 1m+ in diameter and contain thousands of nuclei • Can reproduce asexually or sexually

15. Phylum Acrasiomycota • Consist of the cellular slime molds • Spend part of their life as a single amoeboid cell • Forms a mass, like a plasmodium, when food is scarce but is multicellular with plasma membranes • Cells are haploid for their entire life cycle

16. Phylum Oomycota • Water molds • Appear white and fuzzy • Produce flagellated reproductive cells • Downy mildews • Have caused major crop destruction • Phytophthorainfestans: responsible for the Irish potato famine of the 1840’s