Lecture 15: Protists

Overview

• Focus on the supergroups of eukaryotes, specifically Chrome Alveolata and Excavata.
• Chrome Alveolata can be further divided into clades: Alveolates and Strameno piles.

Chrome Alveolata

Alveolates

• Dinoflagellates:
  • Mostly marine and planktonic.
  • Notable for producing toxins causing red tides.
  • Some are bioluminescent.
  • Can be photosynthetic partners of corals.
• Apicomplexans:
  • All are parasites with complex life cycles.
  • Notable member: Plasmodium spp., responsible for malaria.
• Ciliates:
  • Covered in cilia used for movement.
  • Heterotrophs that eat bacteria.

Strameno piles

• Diatoms:
  • Photosynthetic and planktonic.
  • Have unique complex silica shells.
• Golden Algae:
  • Photosynthetic plankton forming branching colonies.
• Brown Algae:
  • Kelp or seaweed; superficially similar to plants.
  • Photosynthetic and multicellular.
• Oomycetes:
  • Saprobes or parasites; superficially similar to fungi.
  • Notable for causing potato blight.

Excavata

Diplomonads

• Characterized by having two non-identical haploid nuclei.
• Reduced mitochondria known as mitosomes.
• Notable member: Giardia lamblia, causing hikers' diarrhea.

Parabasalids

• Reduced mitochondria.
• Have flagella and an axostyle for attachment.
• Notable members:
  • Trichomonas vaginalis: Causes trichomoniasis.
  • Trichonympha spp.: Digest cellulose in termites.

Euglenozoans

• Possess flagella and are mixotrophs (both heterotrophic and autotrophic).
• Notable parasite: Trypanosoma brucei, causing African sleeping sickness.

Additional Notes

• Protozoa: An informal term sometimes used for single-celled heterotrophic protists.
• End of material for Exam 1.

This lecture covered a significant amount of information on protists, focusing on their classification, characteristics, and some notable members and their impacts.