1. Chapter 20: Protists
Biology- Kirby

2. 20-1: The Kingdom Protista
Protist- any organism that is not a plant, animal, fungus, or prokaryote.
Protists are eukaryotes, and most are unicellular.
The first eukaryotic organisms on Earth were protists (1.5 billion years ago).

3. 20-1: The Kingdom Protista
3 types of protists:
Animallike- heterotrophs
Plantlike- autotrophs
Funguslike- external digestion such as decomposers or parasites.

4. 20-2: Animallike Protists: Protozoans
There are 4 types of protozoans classified by their movement:
Zooflagellates
Sarcodines
Ciliates
Sporozoans

5. 20-2: Animallike Protists: Protozoans
Zooflagellates- move through aquatic environments with flagella.
They can have more than 1 flagella.
Able to absorb food through cell membrane.
Most reproduce asexually by mitosis and cytokinesis.
Some reproduce sexually by meiosis and the formation of gametes.

6. 20-2: Animallike Protists: Protozoans
Sarcodines- use pseudopods for feeding and movement.
Pseupod- “false foot”
Example: Amoeba- capture and digest food by forming a food vacuole with its cytoplasm.
They reproduce by mitosis and cytokinesis.

7. 20-2: Animallike Protists: Protozoans
Ciliates- use cilia for feeding and movement.
Cilia- short hairlike projections similar to flagella. Cilia move together, or beat, and move the organism very quickly.
Example: Paramecium- have a macronucleus and a micronucleus.
Cilia sweep food into the gullet.

8. 20-2: Animallike Protists: Protozoans
Continued:
Waste exit through an anal pore in the membrane.
A cavity called contractile vacuole holds and expels water.
Usually reproduce asexually by mitosis and cytokinesis. Under stress, paramecium undergo conjugation.

9. 20-2: Animallike Protists: Protozoans
Sporozoans- do not move on their own; parasitic.
Attaches itself to a host and lives inside it.
Some animallike protists cause diseases like malaria and African sleeping sickness.
Others are beneficial to organisms.

10. 20-2: Animallike Protists: Protozoans
Zooflagellates
Sarcodines
Ciliates
Sporozoans

11. 20-3: Plantlike Protists-Unicellular Algae
Plantlike protists are called algae.
They contain chlorophyll which makes them appear green.
Some scientists think algae are more closely related to plants; but we consider them to be protists.

12. 20-3: Plantlike Protists-Unicellular Algae
Accessory pigments- absorb light at different wavelengths than chlorophyll- give algae a range of color.
There are 4 phyla of unicellular algae:
Euglenophytes
Chrysophytes
Diatoms
Dinoflagellates

13. 20-3: Plantlike Protists-Unicellular Algae
Euglenophytes:
Plantlike protists that have 2 flagella and no cell wall.
Have an eyespot which allows the organism to find sunlight.
Can also live as heterotrophs by absorbing nutrients.

14. 20-3: Plantlike Protists-Unicellular Algae
Chrysophytes:
Means “golden plants” because they have gold-colored chloroplasts.
Diatoms:
Produce thin cell walls made of silicon which make the walls look like glass.

15. 20-3: Plantlike Protists-Unicellular Algae
Dinoflagellates:
Half are autotrophs, half are heterotrophs.
Many are luminescent and give off light when agitated by sudden movement in water.

16. 20-4: Plantlike Protists-Red, Brown, & Green Algae
There are 3 phyla of multicellular algae:
Red algae
Brown algae
Green algae

17. 20-4: Plantlike Protists-Red, Brown, & Green Algae
Red algae:
Able to live deep in the water.
Have chlorophyll a and reddish accessory pigments called phycobilins.
Important to the formation of coral reefs.

18. 20-4: Plantlike Protists-Red, Brown, & Green Algae
Brown algae:
Contain chlorophyll a and c, and a brown accessory pigment called fucoxanthin.
Largest and most complex of the algae.
Live in cool, shallow waters.

19. 20-4: Plantlike Protists-Red, Brown, & Green Algae
Contain chlorophyll a and b, and cellulose in cell walls.
Live in fresh and salt water.
Unicellular green algae- 2 flagella & single chloroplast.
Colonial green algae- cells are stacked.
Multicellular green algae- has specialized cells & lives on rocky coasts.

20. 20-4: Plantlike Protists-Red, Brown, & Green Algae
Green algae Reproduction:
Life cycle includes both a diploid and haploid generation.

21. 20-5: Funguslike Protists
Funguslike protists are heterotrophs that absorb nutrients from dead/decaying matter.
Slime molds- funguslike protists that recycle organic material.
Cellular slime molds- individual cells remain separated during life cycle.
Acellular slime molds- cells fuse to form large cells with many nuclei called plasmodia.

22. 20-5: Funguslike Protists
Water molds- thrive on dead/decaying matter in water & some are plant parasites on land.
Produce thin filaments called hyphae which aid in reproduction.
Slime and water molds are very beneficial because they help decompose matter, but some can cause plant diseases.