Introduction to Kingdom Protista Notes

Introduction to Kingdom Protista

General Information

• Ernest Haeckel: Credited as the first to use the term "Protista" in 1886.

• Endosymbiotic Theory: Explains the origin of eukaryotic organisms.

  • A larger prokaryotic cell engulfs a smaller aerobic prokaryotic cell.
  • This leads to the development of mitochondria and chloroplasts.
  • The engulfed prokaryote lives within the larger cell.

• Kingdom Protista: A very diverse group of eukaryotic organisms.

• Nickname: Often nicknamed the "Junk Drawer Kingdom" due to its diverse and not well-organized nature; it contains only 1 phyla.

• Classification: The current classification of organisms is not set in stone and is subject to change with new scientific findings.

  • Scientists predict there could be 10-12 more kingdoms in the future.

• Classification Method: Currently, the best method for classifying protists is based on how they obtain nutrition.

  • This method divides protists into three major categories: Plant-like, Animal-like, and Fungus-like.

Protist Categories

• Plant-Like Protists:

  • Autotrophic: They produce their own food through photosynthesis.
  • Ancestors of modern-day plants.

• Animal-Like Protists:

  • Heterotrophic: They obtain nutrition by consuming other organisms.
  • Ancestors of multicellular animals.

• Fungus-Like Protists:

  • Decomposers: They obtain nutrients by breaking down organic matter.
  • Ancestors of modern-day fungi.

Protist Cell Structures and Functions

• Contractile Vacuole (All): Removes excess water from the cell.

• Flagella (Euglena): Facilitates movement.

• Eyespot (Euglena): Detects light, aiding in photosynthesis.

• Chloroplast (Euglena): Traps sunlight for photosynthesis.

• Pseudopod (Amoeba): "False foot" used to wrap around and ingest food particles.

• Food Vacuole (Amoeba/Paramecium): Stores food; lysosomes aid in digestion.

• Cilia (Paramecium): Used for movement.

• Pellicle (Euglena/Paramecium): Tough outer layer that provides protection.

Specific Protist Examples

• Alga: Example of a plant-like protist.

  • Autotrophic.
  • Contains: Nucleus, Chloroplast, Pellicle, Contractile vacuole, Eyespot, Flagella.

• Amoeba: Example of an animal-like protist.

  • Heterotrophic.
  • Contains: Food vacuole, Contractile vacuole, Ectoplasm, Endoplasm, Pseudopods, Nucleus.

• Paramecium: Example of an animal-like protist.

  • Heterotrophic.
  • Contains: Macronucleus, Micronucleus, Cilia, Gullet, Oral groove, Contractile vacuole, Cell membrane.