Protists are eukaryotic organisms that are not classified as plants, animals, fungi, or bacteria. They can be unicellular or multicellular. Protists are primarily classified based on their method of nutrition - animal-like protists are heterotrophs, plant-like protists contain chloroplasts and perform photosynthesis, and fungus-like protists decompose dead organic material. Common protists include paramecium, amoebas, euglena and various types of algae. Protists play important roles in ecosystems by recycling nutrients, being a food source, and in some cases causing harmful algal blooms.

2. 1. Any organism not classified as a—plant, animal,
fungus, or bacteria (prokaryote).
2. Protists are eukaryotic having a distinct nucleus
and organelles.
3. Most protists are unicellular (one-celled) but
some are multicellular.

3. 4. Protists are primarily classified according to
how they obtain nutrition:
a. Animal-like—heterotrophs
(eat other organisms)
b. Plant-like—autotrophs
They contain chloroplasts
and make their own food
(photosynthesis).
a. Fungus-like—
Decomposers/Heterotrophs
Didinium
Paramecium
eating
Green like plants!
Water mold

4. Animal-like Protists (Protozoans)
1. Method of Movement:
a. Cilia—hair-like projections used for movement and
feeding
b. Cytoplasmic streaming—pseudopod (false foot) extends
and cytoplasm streams into it.
Video
Video

5. 2. Paramecium:
Nucleus
Cilia
Cell Membrane
Contractile Vacuole
Collects and removes excess H2O
(Maintains homeostasis)
Oral Groove
Used to collect food

6. 3. Amoeba:
Nucleus
Contractile Vacuole
Pseudopod
(False foot)

7. 4. Importance of Animal-like
Protists:
a. Harmful
i. Disease-causing parasites spread
by insect bites
1. Malaria—Plasmodium spread
by mosquito
2. African Sleeping Sickness—
Trypmosoma
spread by Tsetse fly

8. b. Beneficial
i. Recycles nutrients by breaking down dead matter
ii. Food source—for other organisms
iii. Mutualism—both organisms benefit
Example: Trichonympha—makes it
possible for termites to eat
wood. Termites do not have the
enzymes to digest wood.

9. Plant-like Protists
1. Method of Movement:
a. Flagellum—whip-like structure used for movement
2. Euglena:
Nucleus
Contractile Vacuole
Chloroplasts
Flagella
Eyespot For photosynthesis
(light)
Video

10. 3. Unicellular Algae:
a. Phytoplankton provides a source of nourishment for
other organisms
b. Protists recycle sewage and waste materials.

11. C. Algal blooms are harmful when overgrown—deplete water of
nutrients consequently killing fish.
Algal blooms called Red Tides cause illness, paralysis, and
death of fish and even humans.

12. 4. Multicellular Algae:
a. Examples---
i. Red Algae
ii. Green Algae
iii. Brown Algae

13. 5. Uses of Algae:
a. Algae is a good food source for life in
the oceans.
b. Algae produces much of Earth’s oxygen
through photosynthesis.
c. Algae is used to make sushi, ice cream,
salad dressing, plastics, paint, agar.

14. Fungus-like Protists:
1. Examples—
a. Slime molds
b. Water molds

15. 2. Importance of Fungus-like Protists:
a. Beneficial—
Recycles dead organic material. Results
in rich, topsoil providing nutrients for
plants.

16. b. Harmful—
P. Infestans (water mold) caused
Great Potato Famine in Ireland.
This lead to the mass starvation of
1 million Irish people.