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Chapter 20 - Protists. What’s in a name?. Derived from Greek word meaning “The Very First” – Proto Side 1 538 - 542. Characteristics:. Eukaryotic Unicellular - may be Colonial or filamentous (Spirogyra and Volvox) Plant-like, Animal-like, or Fungus-like characteristics.
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What’s in a name? • Derived from Greek word meaning “The Very First” – Proto Side 1 538 - 542
Characteristics: • Eukaryotic • Unicellular - may be Colonial or filamentous (Spirogyra and Volvox) • Plant-like, Animal-like, or Fungus-like characteristics
Where did they come from? • Lynn Margulis’ Endosymbiont Hypothesis – Present day Protists evolved from the symbiotic relationship of prokaryotes that lived together until eventually, they had to remain together. • Used organelle evidence: • Mitochondria and chloroplasts are actually Eubacteria & blue-green bacteria (now Archaeabacteria). • Flagella were spirochetes • Further proof provide by the then algae, Cyanophora paradoxa when their chloroplasts were removed, they were actually blue-green bacteria which were able to reproduce & multiply
Animal-like Protists Protozoans – First animals • Classification is based on method of mobility • Ciliophora - Ciliates • Paramecium, Stentor, Didinium, Vorticella • Have cilia for mobility
Protozoan Structures • Contractile vacuole – Regulates water pressure • Trichocysts – defense mechanisms • Macronucleus – binary fission • Micronucleus – Conjugation • Gullet – food is packaged into food vacuoles • Oral groove – cilia lined to sweep food into gullet • 538 539 39273P
Paramecium Euplotes Paramecium w/ trichocysts Didinium Stentor Vorticella
Flagellates • Peranema Giardia (Giardiasis),Trypanosoma and Chilomonas • Have flagella for mobility (Peranema - 38601P) • Many are parasitic and cause intestinal distress
Spore forming Protists • Plasmodium (Malaria) & Toxoplasmosis • Nonmotile • Parasitic • Reproduce by forming spores in host cells
Pseudopod Protists • Amoeba, Radiolarians and Formanifera 528 - 536 • Move using pseudopods or false feet 531 • Pseudopods are used for movement and phagocytosis of food • 532, 38894P
Reproduction • Most Protozoa reproduce by binary fission & conjugation (Ciliates) • 532- 535, 538
Plant-like Protists • Classified by their main pigment • Euglenophyta – Euglena576 & 577 • Move using Flagella • Eyespot as a photoreceptor to keep organism in photic zone • May be auto or heterotrophic
2. Dinoflagellates – Fire algae • Dinoflagellates 570 & 571 • 2 flagella • Bioluminesce– gives off light • Produce a neurotoxin – cause Red Tides when they bloom and Paralytic Shellfish poisoning in clams and oysters. 569 • (Blooms concentrate in shell fish then into fish which we eat. Weaken or even kill the weak.)
Red Tides • Caused by a bloom in Dinoflagellates, Karenia (Gymnodinium) breve • Produce neurotoxins • Responsible for large die-offs of marine organisms and seabirds Karenia brevis
Diatoms • Diatoms 563 - 566 • Silica shell • Diatomaceous earth as filtering and also abrasives • Store food as oil (buoyancy)
4. Green algae • Volvox and Spirogyra 547 & 548 • May have flagella or be immobile like Spirogyra • Main pigment is Chlorophyll a & b
Fungus-like Protists • 544 & 545 Video • Slime molds – Found in nutrient rich materials like mulch, compost and thickwet lawns. • Absorptive heterotrophs • Witches’ butter
Volvox Spirogyra Euglena Vorticella Amoeba Stentor Peranema Blepharisma Paramecium & Didinium Diatoms