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