1. Protists Chapter 20 Objective:
11.0 Classify animals according to type of skeletal structure, method of fertilization and reproduction, body symmetry, body coverings, and locomotion.
Examples: skeletal structure -—vertebrates, invertebrates;
fertilization—- external, internal;
reproduction -—sexual, asexual;
body symmetry—- bilateral, radial, asymmetrical;
body coverings—- feathers, scales, fur;
locomotion—- cilia, flagella, pseudopodia
Protists Chapter 20

2. What is a Protist?
Any eukaryote that is not an animal, plant, or fungus
Most are unicellular, but not all
Can be classified as animal-like, plant-like, or fungus-like

3. Animal-like Protists (Section12-2)
Heterotrophs
4 phyla, based on means of movement:
Zooflagellates – swim through their aquatic environments using flagella
Sarcodines – move via temporary cytoplasmic projections called pseudopods
Ciliates – use _________ for feeding and movement
Sporozoans – do not move on their own; are parasites

4. Zooflagellates Can generally absorb food through their cell membranes
Nutrients from decaying organic matter in water
From the bodies of other organisms in which they live
Reproduction can be asexual by mitosis and cytokinesis, or sexual by meiosis.

5. Sarcodines Pseudopods are used for feeding and movement. EX: amoebas
Reproduce asexually by mitosis and cytokinesis
Source:

6. Ciliates Cilia are short hair-like projections.
The rapid beating of cilia propels ciliates through water.
Most ciliates contain two different nuclei:
Macronucleus – keeps multiple copies of the genes
Micronucleus – contains a “reserve” copy of all the cell’s genes
Obtain food by using cilia to sweep food into an indentation called the gullet
Reproduce asexually by _____ and _____, and sexually by conjugation.

7. Paramecium
Source:

8. Sporozoans Live as parasites on everything from worms to humans
Reproduce by sporozoites

9. Protists and Disease
Malaria – caused by the sporozoan Plasmodium; spread by mosquito bites
African sleeping sickness – caused by zooflagellate Trypanosoma; spread by tsetse fly bites
Amebic dysentery – caused by parasitic Entamoeba
Dysentery – flagellate Giardia

10. Plant-Like Protists: Unicellular Algae (Section 20-3)
Contain chlorophyll and carry out photosynthesis
Commonly called “algae”
Seven major phyla, classified according to a variety of cellular characteristics (types of chlorophyll or accessory pigments present):
First 4 phyla are unicellular
Last 3 contain many multicellular organisms

11. 1. Euglenophytes
Plant-like, but have 2 flagella (like ???) and no cell wall
Eyespot – cluster of reddish pigment that helps organism find sunlight
Reproduce asexually by binary fission
Source:

12. 2. Chrysophytes “yellow plants”
Includes yellow-green and golden-brown algae
Chloroplasts contain bright yellow pigment

13. 3. Diatoms
Produce thin, delicate cell walls rich in silicon (Si) – the main component of glass.
Look like etched petri dishes
Source:

14. 4. Dinoflagellates
About half are photosynthetic; others are heterotrophs
2 flagella, which wrap around the the organism in grooves
Reproduce asexually by binary fission
Can luminesce when agitated

15. Source:
Source:

16. Ecology of Unicellular Algae
Compose most of the phytoplankton – plant microorganisms at the bottom of food chains
Algal blooms (“red tide”) –
Protists can break down sewage in water
Excessive waste creates large populations of euglenophytes, which deplete nutrients in the water.
When they die, they can deplete oxygen supplies needed by other organisms.

17. Plant-like Protists: Red, Brown, and Green Algae (Section 20-4)
Mostly multicellular
Reproductive cycles similar to plants
Many with cell walls and photosynthetic pigments identical to plants

18. Red Algae Phylum Rhodophyta (“red plants”)
Contain chlorophyll  and reddish accessory pigments called phycobilins, which can absorb blue light, allowing them to harvest light energy at great depths
Can actually be green, purple, or redish-black in color
Play a role in coral reef formation
Lack flagella and centrioles

19. Brown Algae Phylum Phaeophyta (“dusky plants”)
Contain chlorophyll  and c, as well as a brown accessory pigment (fucoxanthin)
Dark yellow-brown color
EX: giant kelp
Source:

20. Green Algae Phylum Chlorophyta (“?????”)
Same photosynthetic pigment and cell wall composition as plants
Contain chloroplast a and b
Life cycles of many include both a diploid and a haploid generation (“alternation of generations”)

21. Alternation of Generation
Source:

22. Fungus-like Protists (Section 20-5)
Fungi
Both
Heterotrophs;
Absorb nutrients from dead/decaying matter
Cell walls made of chitin
Have centrioles

23. Molds Slime Molds: Water Molds:
Cellular slime molds – individual cells remain distinct (separated by cell membranes) throughout life
Acellular slime molds – pass through a life stage in which cells fuse to form large cells with many nuclei
Water Molds:
Thrive on dead or decaying matter in water OR are plant parasites on land
EX: white fuzz on a dead fish in the water