1. Chapter 20, Biology Textbook Page 496
The Protists
Chapter 20, Biology Textbook
Page 496

2. The Kingdom Protista
Protists are eukaryotes that are not members of the kingdoms plantae, animalia, or fungi
Most Protists are unicellular, however some are multicellular

3. Classification?
At present, biologists do not agree on how to classify protists
One way to artificially classify them is in the way they obtain nutrition.

4. Heterotrophic or Animallike Protists
At one time, they were known as Protozoa.
The four phyla of these are distinguished by their means of movement
They are zooflagellates, sarcodines, ciliates, and sporozoans

5. Zooflagellates
They swim using flagella and are classified in the phylum zoomastiginia.
Most absorb food through their cell membranes
Can reproduce asexually or sexually

6. Sarcodines
Move and feed by temporary cytoplasmic projections known as pseudopods.
The cytoplasm of the cell streams into the pseudopod, and the rest of the cell follows.
This is amoeboid movement.

7. Sarcodines-cont.
A food vacuole is a small cavity in the cytoplasm that temporarily stores food.
Amoebas surround their meal and then take it inside themselves.

8. Ciliates
Phylum ciliophora named for cilia, which are hairlike projections similar to flagella
They use cilia for feeding and movement
Trichocysts are small bottle-shaped structures used for defense

9. Ciliates-cont.
Contain a macronucleus, which keeps copies of its genes.
Contain a micronucleus, which keeps a reserve copy of all of the cell’s genes.

10. Ciliates-cont.
Use cilia to sweep food into the gullet, an indentation on one side.
Waste is emptied when a food vacuole fuses with the anal pore.
Reproduce by conjugation

11. Sporozoans Phylum sporozoan.
They do not move on their own and are parasitic.
Some cause serious diseases such as malaria.
Reproduce by sporozites.

12. Other Protistan diseases
African sleeping sickness—caused by trypanosomes passed along by the tsetse fly.
Amebic dysentery—caused by Entamoeba and Giardia.

13. 20-3 Plantlike Protists: Unicellular Algae
Chlorophyll and accessory pigments allow algae to harvest and use the energy from the sunlight.
Euglenophytes are plantlike protists that have two flagella but no cell wall

14. Unicellular Algae-cont.
Chrysophyta are a diverse group of plantlike protists that have gold-colored chloroplasts
Diatoms produce thin, delicate cell walls rich in Silicon (Si)-the main ingredient in glass.

15. Unicellular Algae-cont.
Dinoflagellates have two flagella.
Half are photosynthetic the other half live as heterotrophs.

16. Ecology of Unicellular Algae
Phytoplankton constitute the population of small, photosynthetic organisms found near the surface of the ocean

17. Algal blooms
Euglenophytes and other algae absorb organic matter directly and use it for food.
They are important recyclers of sewage and other waste materials
Problem: Can grow to enormous masses, die, and deplete a body of water of its oxygen killing fish and other organisms

18. Algal blooms-cont.
Some algal blooms can produce a potentially fatal toxin.
Karenia can cause what’s known as a red tide.
They are eaten by shellfish, which concentrate the toxin. Eating these shellfish could cause, illness, paralysis, and even death.

19. Red tide (algal bloom)

20. Plantlike Protists: Red, Green, Brown Algae
Red algae live at great depths due to their efficiency in harvesting light
Red algae contain chlorophyll a and reddish accessory pigments known as phycobilins.

21. Brown Algae Contain chlorophyll a and c
Contain a brown accessory pigment known as fucoxanthin

22. Green Algae
Share many characteristics with plants, including their photosynthetic pigments and cell wall composition.
The life cycles of most algae include both a diploid and haploid generation

23. Green Algae