Kingdom Protista Overview

Introduction to Kingdom Protista

• "Junk Drawer" Kingdom: Diverse eukaryotes not fitting into other kingdoms.
• General Characteristics:
  • Eukaryotic and mostly unicellular (some colonial/multicellular).
  • Varied nutrition methods and habitats (mostly aquatic).
  • Plankton: Protists in water, crucial for ecosystems.
  • Osmoregulation: Contractile vacuoles (e.g., Paramecium) manage water balance.

Protists & Human Welfare/Ecology

• Diseases: Malaria (Plasmodium), African Sleeping Sickness (Trypanosoma).
• Ecological Roles:
  • Phytoplankton: Major oxygen producers and food chain bases.
  • Decomposers: Fungus-like protists.
  • Industrial Uses: Diatomaceous earth (filters), red algae (agar, carrageenan).
  • Bioluminescence: Seen in some dinoflagellates.
• Red Tides: Harmful algal blooms caused by dinoflagellates.

Classification of Protists

• Animal-like Protists (Protozoa):

  • Heterotrophs, often motile.
  • Zooflagellates: Move with flagella (e.g., Trypanosoma).
  • Sarcodines: Use pseudopods for movement/feeding (e.g., Amoeba).
  • Ciliates: Use cilia, complex (e.g., Paramecium).
  • Sporozoans: Non-motile, parasitic (e.g., Plasmodium).

• Plant-like Protists (Algae):

  • Photosynthetic autotrophs.
  • Unicellular Algae:
    • Euglenophytes: Photosynthetic, motile (e.g., Euglena).
    • Dinoflagellates: Bioluminescent, cause red tides.
    • Chrysophytes: Golden algae, store oil.
    • Diatoms: Silica shells, major phytoplankton.
  • Other Algae:
    • Green Algae: Chlorophyll, diverse forms (e.g., Chlamydomonas).
    • Brown Algae: Large, marine (e.g., kelps).
    • Red Algae: Deep-sea, pigments for deeper light absorption.

• Fungus-like Protists:

  • Heterotrophs, decomposers/parasites.
  • Water Molds: Parasitic/decomposing.
  • Slime Molds: Amoeboid movement in life cycle.

Reproduction in Protists

• Cell Types:
  • Haploid (N) and Diploid (2N).
• Asexual Reproduction: Binary fission, rapid but no variation.
• Sexual Reproduction: Conjugation (genetic exchange), gamete fusion.
• Alternation of Generations: Multicellular haploid/diploid stages.
• Plasmodium Life Cycle: Complex involving two hosts (humans, mosquitoes).

Evolution of Multicellularity

• Colony vs. Multicellularity:
  • Colony: Cells reproduce and remain attached.
  • Multicellular: Specialized cell functions.

Miscellaneous Information

• Protists vs. Bacteria: Protists are eukaryotes; bacteria are prokaryotes.
• Viruses: Non-living, require host cells to reproduce.
• Lichen: Symbiosis between fungi and algae.
• Phyla Matching:
  • Pyrrophyta: Dinoflagellates
  • Sporozoans: Sporozoans
  • Myxomycota: Acellular slime molds
  • Phaeophyta: Brown algae
  • Chrysophyta: "Golden plants"
  • Chlorophyta: Green algae
  • Euglenophyta: Euglenophytes
  • Acrasiomycota: Cellular slime molds
  • Zoomastigina: Zooflagellates
  • Oomycota: Water molds
  • Bacillariophyta: Diatoms
  • Sarcodina: Amoebas
  • Rhodophyta: Red algae
  • Ciliophora: Ciliates