Kingdom Protista

Domain: Eukarya

Characteristics:

  • Eukaryotic cells with a nucleus and membrane-bound organelles
  • Mostly unicellular
  • More complex than bacteria
  • Diverse group not fitting into other kingdoms (Plants, Animals, Fungi)

Subkingdoms:

  • Protozoa
  • Algae
  • Slime molds

Additional Characteristics:

  • Modes of nutrition: autotrophic, heterotrophic, or mixotrophic
  • Found in various environments (aquatic and terrestrial)

Modes of Nutrition

Autotrophic:

  • Produce own food via photosynthesis or chemosynthesis
  • Energy: Sunlight (photoautotrophs) or inorganic chemicals (chemoautotrophs).
  • Carbon: CO₂

Heterotrophic:

  • Requires consumption of other organisms
  • Energy from organic compounds
  • Carbon from organic molecules

Mixotrophic:

  • Switch between autotrophic and heterotrophic
  • Energy from light and organic material
  • Carbon from both CO₂ and organic molecules

Protozoa

  • Mostly unicellular and heterotrophic
  • Specialize in locomotion
  • Phyla: Sarcodina, Mastigophora, Ciliophora, Apicomplexa

Types of Protozoa:

Sarcodina:
  • Irregular structures using pseudopodia for movement
  • Habitat: aquatic/moist environments
  • Example: Amoeba
Mastigophora:
  • Varied shapes using flagella for movement
  • Habitat: aquatic, terrestrial, or hosts
  • Examples: Trypanosoma, Giardia
Ciliophora:
  • Well-defined shapes with cilia for movement
  • Habitat: mostly aquatic
  • Example: Paramecium
Apicomplexa:
  • Complex life cycles, non-motile in mature stages
  • Parasitic lifestyle, relying on hosts
  • Example: Plasmodium (causes malaria)

Algae

  • Can be unicellular or multicellular
  • Autotrophic, performing photosynthesis
  • Divisions based on photosynthetic pigments:
    • Euglenophyta
    • Chlorophyta
    • Chrysophyta
    • Phaeophyta
    • Rhodophyta

Types of Algae:

Euglenophyta:
  • Contains pellicle and eyespot
  • Habitat: freshwater, soil
  • Example: Euglena
Chlorophyta:
  • Contains chlorophyll a and b; cellulose cell walls
  • Habitat: mostly freshwater
  • Example: Chlorella
Chrysophyta:
  • Contains golden-brown pigments
  • Habitat: freshwater, some marine
  • Example: Dinobryon
Phaeophyta:
  • Contains brown pigments
  • Habitat: marine; forms kelp forests
  • Example: Kelp
Rhodophyta:
  • Contains red pigments
  • Habitat: marine, especially deeper waters
  • Example: Corallina

Slime Molds

  • Can be unicellular or multicellular
  • Found in decomposing organic matter; heterotrophic
  • Types: Plasmodial (multinucleate) and Cellular (aggregates)

Cyanobacteria

  • Domain: Bacteria (Prokaryotic)
  • Photosynthetic using chlorophyll a
  • Habitat: freshwater, can thrive in extreme conditions
  • Examples: Anabaena, Nostoc

Lab Demonstration

Materials:

  • Pond water sample
  • Glass slide, cover slip, microscope

Method:

  1. Place a drop of pond water on slide, cover with slip
  2. Observe under microscope (avoid 100x lens)
  3. Record and draw organisms observed

Post Lab Questions

  1. Difference between autotrophs and heterotrophs?
  2. Complete worksheet on Kingdom Protista classification, including
    • Domain, Kingdom, Subkingdom
    • Phyla of Protozoa and their unique characteristics
    • Divisions of Algae and their unique characteristics
    • Diagrams of locomotion structures for motile protozoa