1. Chapter 8-1
What are Protists?

3. What are Protists? –the “Junk Drawer” kingdom
A protist is a member of a group of eukaryotic organisms which have a membrane-bound nucleus.
Most protists reproduce asexually, though some can reproduce sexually
Protists are extremely diverse and share characteristics with plants, animals, and fungi but are not classified as any of these groups

4. What are Protists? General characteristics-
Most are unicellular, but some, such as the giant kelp, are multicellular & can grow to be as big as 100 meters
Live in moist surroundings
Some move and some don’t
Some can make their own food, while others are consumers or decomposers
Scientists classify protists as plant-like, animal-like, or fungus-like based on which group they most resemble.
They are classified by how they obtain food

5. Three kinds of Protists-
Plant-like
Animal-like
Fungus-like

6. Plant-like Protists
Like plants, these protists use chlorophyll for photosynthesis
(takes place in chloroplasts)
Almost all live in water
Examples include:
Algae
Diatoms
Dinoflagellates
Euglenoids

7. Plant-like Protists- Algae
Algae are plant-like protist that perform photosynthesis. They can be either multicellular or unicellular.
Red algae
Used to make ice cream, marshmallows & shampoo
Brown algae
Known as “seaweed”
Green algae

8. Plant-like Protists- Diatoms
A type of microscopic plantlike protist with a hard outer wall is a diatom
Diatoms
Unicellular with glasslike cell walls
Used in silver polish, toothpaste & insulation

9. Plant-like Protists- Dinoflagellates
Dinoflagellates are unicellular plantlike protists that use flagella to move.
Dinoflagellates
They have many pigments so they come in several colors
They have 2 flagella that allow them to swirl around as they move
They glow in the dark & look like fireflies at night

10. Plant-like Protists- Euglenoids
A Euglenoid is a unicellular plant-like protist that has a flagellum at one end of its body. It has no cell wall. Instead it has a rigid rubbery coat called a pellicle.
Euglenoids
Have eyespots that
respond to changes in
light
Tell the euglena when to perform photosynthesis
Produce food by photosynthesis

11. Click on the image below to observe a Euglena swimming with it’s flagella

12. The importance of Algae
Algae provide food for animals and animal-like protists, and provide shelter for many aquatic organisms such as sea otters.
They are plant-like but have holdfasts rather than roots.
Algae can help remove pollution from the water.

13. Algae are thought to cause Red Tides
Pollution can be a food source for algae, allowing the population of algae to increase quickly.
This overproduction can lead to Red Tides, which can be dangerous to other aquatic animals & humans

14. Animal-like Protists: Protozoans
Protozoans are protists that resemble tiny animals
Protozoans are unicellular and mostly live in wet environments.
Protozoans do not have chloroplasts and cannot make their own food.
They are consumers and some are parasites

15. Animal-like Protists- Ciliates
Cilia are short, hair-like structures that grow on the surface of some protists.
Protists with cilia are called Ciliates.
Cilia cover the surface of the cell and move a protist through water.
Ciliates reproduce asexually, but they can exchange some genetic material through a process called conjugation.

16. Animal-like Protists- Ciliates
A paramecium is a protist with cilia and two types of nuclei.
A paramecium gets its food by forcing water into a groove in its side.

17. Click on the video below to observe a paramecium feeding!

18. Animal-like Protists- Flagellate
A Flagellate is a type of protozoan with one or more flagella.
Flagellates eat decaying matter.

19. Animal-like Protists- Sarcodines
Sarcodines are animal-like protists with no specific shape.
An amoeba is one common Sarcodine.
An amoeba moves and obtains nutrients by using pseudopods, which means temporary or false foot.
Amoeba form pseudopods by slowly pushing their cytoplasm against the soft, flexible cell membrane.

20. Animal-like Protists: Protozoa cont’
Amoeba use their pseudopods to engulf their food and form a food vacuole
They are found in soil, salt & fresh water, and use a contractile vacuole to get rid of excess water

21. Click on picture below to observe an Amoeba in action!!!

22. Some protozoans are parasites and can cause disease like malaria.

23. Animal-like Protists: Protozoa cont’

24. Animal-like Protists: Protozoa cont’
Spore forming protist, Plasmodium

25. Fungus-like Protists
Funguslike protists share many characteristics with fungi.
Slime molds are funguslike protists composed of cell material and nuclei floating in a slimy mass.
Most slime molds absorb nutrients from other organic matter in their environment.

26. Funguslike Protists
A water mold is a funguslike protist that lives as a parasite or feeds on dead organisms.
Slime molds and water molds usually reproduce sexually when environmental conditions are harsh or unfavorable.

27. Importance of Funguslike Protists
Funguslike protists play a valuable role in the ecosystem by breaking down dead plants and animals, making nutrients available for living organisms.
Many funguslike protists attack and consume living plants.
Water mold destroyed more than half of Ireland’s potato crop in 1845