Plant-Like Protists (Algae)

1. Plant-Like Protists (Algae) • Autotrophs – photosynthetic, have chloroplasts, all have chlorophyll a • Classified by pigment types / color group, food storage, cell wall composition (7 phyla) • Produce most O2 on earth • No roots, stems, leaves – make gametes in single-celled gametangia • Most aquatic, have flagella at some stage of life cycle • Store starch in pyrenoids • Unicellular (eg. Phytoplankton), multicellular (eg. seaweeds) or colonial

2. Plant-Like ProtistsPhylum Chlorophyta – Green Algae • Like plants, have chlorophyll a and b, carotenoids, food stored as starch, cellulose in cell walls  common ancestor or plants evolved from green algae • Most aquatic, some terrestrial (moist soil, tree trunks – Protococcus) • some symbiotic with invertebrates (corals) or fungi (lichens) • Some motile, some sessile

3. Symbiosis w/ Fungi: Lichens Crustose & Foliose

4. Symbiosis with Cnidarians Some anemones, corals, and jellyfish have symbiotic algae (zooxanthelae)

5. Unicellular

6. Colonial

7. Multicellular / Filamentous

8. What type of life cycle is this? What is the only step that uses meiosis?

9. Giant kelp Plant-Like ProtistsPhylum Phaeophyta – Brown Algae • Multicellular • Chlorophyll a and b, plus fucoxanthin brown accessory pigment • Most marine, include seaweeds and kelp • Sargassum – floating seaweed • Mycrocystispyrifera – giant kelp • sessile Kelp

10. Plant-Like ProtistsPhylum Rhodophyta – Red Algae • Chlorophyll a and phycobilins – red accessory pigments that absorb light deep in water  can live in deeper water than other algae • Most are marine seaweeds, sessile

11. Plant-Like ProtistsPhylum Bacillariophyta - Diatoms • Unicellular • Cell walls = shells of silicon dioxide  two halves that fit like a pill box  found in beach sand, used in toothpaste, etc. • Centric – round or triangular, mostly marine • Pennate – rectangular, mostly freshwater • Abundant in phytoplankton

12. Plant-Like ProtistsPhylum Dinoflagellata - Dinoflagellates • Usually unicellular, have two flagella perpendicular to each other • Cell walls made of celluloseplates that resemble armour – ex.: Cerratium • Most yellow to brown – carotenoids plus chlorophyll a and c • A few colorless heterotrophs • Some bioluminesce – genus Noctiluca • Some produce toxins & red pigment  “red tides”

13. Ceratium Dinoflagellate “armour” Red tide

14. Bioluminescence

15. Plant-Like ProtistsPhylum Chrysophyta – Golden Algae • Unicellular, chlorophyll a and b, yellow due to carotenoids • Two flagellaon opposite ends of cell • Most live in freshwater • Form highly resistantcysts survive in frozen or dry lakes • Store energy as oils  formation of petroleum  new biofuels?

16. Plant-Like ProtistsPhylum Euglenophyta - Euglenoids • Unicellular, plant-like and animal-like: • No cell walls, have protein pellicle • Chloroplasts (if raised in presence of light) • Eyespot sensitive to light • Contractile vacuole • Chlorophylls a and b, carotenoids • Most live in freshwater, some in moist soil and animal digestive tracts