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Chapter 20 - Protists
Characteristics:• Eukaryotic
• Unicellular - may be colonial or filamentous (Spirogyra and Volvox)
• Animal-like, Plant-like, or Fungus-like characteristics
ENDOSYMBIOTIC THEORY
Animal-like Protists “First animals”
• Classification is based on method of mobility
• Four Phyla:
*** Protozoa
*** Ciliophora
*** Sarcomastigophora
*** Apicomplexa
Phylum ProtozoaPhylum Protozoa
• Amoeba, Radiolarians and Formanifera
• Move using pseudopods or false feet Pseudopods are used for movement and phagocytosis of food
• Entamoeba histolytica – Amoebic dysentery
AmoebaAmoeba Feeding
Feeding
Actinosphaerium
Actinosphaeriumclose up of axial rods
Amoeba proteus
Chaos-chaosshown withParamecium
Arcella
Difflugia
Entamoeba
Entamoeba-cyst
Paramoeba
Phylum Ciliophora
Paramecium, Stentor, Didinium, Vorticella
Have cilia for mobility
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
Paramecium
Stentor
Paramecium w/ trichocysts
Vorticella
Didinium
Euplotes
Didinium feedingParamecium feeding
Phylum SarcomastigophoraPhylum Sarcomastigophora
• Giardia (Giardiasis),Trypanosoma (African Sleeping Sickness carried by Tse Tse fly
• Have flagella for mobility
• Many are parasitic and cause intestinal distress
Phylum ApicomplexaPhylum Apicomplexa
• Plasmodium (Malaria carried by mosquitoe) & Toxoplasmosis
• Nonmotile
• Parasitic
• Reproduce by forming spores in host cells
Malarial Life Cycle
Plant-like ProtistsPlant-like Protists
• Classified by their main pigment
1.1. EuglenophytaEuglenophyta – Euglena
Move using Flagella
– Eyespot as a photoreceptor to keep organism in photic zone
– May be auto or heterotrophic
2. Pyrrophyta – 2. Pyrrophyta – Fire algaeFire algae
• Dinoflagellates have two flagella• Luminescent – give off light• Produce a neurotoxin – cause Red Tides
when they “bloom” and Paralytic Shellfish poisoning in clams and oysters. Blooms concentrate in shell fish then into fish which we eat. Weaken or even kill – biomagnification example
Red Tides
• Caused by a bloom in Dinoflagellates
• Produce neurotoxins
• Responsible for large die-offs of marine organisms and seabirds
Karenia brevis
3.3. Bacillariophyta– Bacillariophyta– DiatomsDiatoms
• Diatoms - Silica shell
• Diatomaceous earth as filtering and also abrasives
• Store food as oil (buoyancy)
4. Chlorophyta. ChlorophytaGreen algaeGreen algae
• Volvox and Spirogyra
• May have flagella or be immobile like Spirogyra
• Main pigment is Chlorophyll a & b
Fungus-like ProtistsFungus-like Protists • Slime molds – Found in nutrient rich
materials like mulch, compost and thick wet lawns.
• Absorptive heterotrophs • 2 stages in life
– Single amoeba-like cells– Mold-like mass that produce spores
Under The Microscope, Animal-Like
Under The Microscope, Plant-Like
Vorticella
Euglena
Volvox Spirogyra
StentorAmoeba
Paramecium & Didinium
Blepharisma
Diatoms
Peranema