Protists• The most diverse kingdom of eukaryotes• All are eukaryoteseukaryotes – have a nucleus and
membrane-bound organelles• Protists often have a very complicated internal
structure: a single cell must do all the functions that we have many different cell types to do.
How are Protists classified?
• Mode of nutrition is used to classify protists into 3 main groups– Protozoa (ingestive, animal-like)– Algae (photosynthetic, plant-like)– Slime molds (absorptive, fungus-like)
Protozoan are classified by how they move
• Pseudopodia
• Cilia
• Flagella
• Non-moving on their own: spores
Rhizopods (like the Amoeba) move with psuedopods
http://shs.westport.k12.ct.us/mjvl/biology/cells/amoeba.gif
•This drawing of an amoeba illustrates the pseudopod.
• Can you recognize the pseudopod in this amoeba?
More Rhizopods: Note the psdeudopods
• Heliozoans
• Radiolarians
• Foraminiferans
Protozoans
• Trypanosoma --------- is the protozoan that causes African sleeping sickness
• Giardia ------------------ causes the diarrhea sickness contracted from contaminated water (yuck! – always bring your own water on hikes!)
www.innovations-report.com/. ../report-19279.html martin.parasitology.mcgill.ca/.../ GIARDIA.HTM
Sporozoans – live inside hosts
parasitol.wkhc.ac.kr/ image/oth/mosq.GIF
•These protozoans may seem harmless since they can’t move on their own, but they use vectors, such as insects, to get them where they want to go.
•Plasmodium (purple in a field of red blood cells) is the protozoan that causes malaria with the help of mosquitoes as the vector.
A common protozoan is the paramecium – can you see the cilia?
http://faculty.plattsburgh.edu/jose.deondarza/research/Photos/Paramecium.jpg
Now that you are a protozoan pro, do you remember the next group of protists – those that
make their own food?
ALGAEALGAEClick to see the correct answer…
Algae
There are 6 main phyla of these plant-like protists:
1. Green algae2. Euglena3. Dinoflagellates4. Diatoms5. Red algae6. Brown algae
Let’s take a look…
Green algae: they are green!!
www.sonoma.edu/biology/ algae/Green.html www.acadweb.wwu.edu/.../ 25_hydrodictyon_40x.jpg http://www.acadweb.wwu.edu/courses/envr429-rm/Robin/images/envr429/27_oedogonium_40x.jpg
•Green algae are thought to be the direct ancestor of land plants
Euglena
http://www.bgbm.org/kusber/images/euglena.gif
The euglena performs photosynthesis like a plant, but has a flagellum and moves around like a protozoan.
http://www.cartage.org.lb/en/themes/Sciences/BotanicalSciences/MajorDivisions/KingdomProtista/Protists/euglena.gif
Dinoflagellates
• have 2 flagella that make them spin; some can secrete dangerous toxins – one example is the red tides caused by Pfiesteria, which lead to fish kills
http://biology.nebrwesleyan.edu/Courses/Labs/Biology_of_Animals/ZooLab9/Dinoflagellates_100X.jpg
http://www.infectiousdiseasenews.com/199906/S9a06587.gif
Diatoms
http://www.nhm.ac.uk/hosted_sites/quekett/Others/Gallery/Helios/diatom.jpg
http://www.lifesci.ucsb.edu/mcdb/research/facilities/microscopy/diatom.jpg
http://www.acnatsci.org/research/biodiv/diatompics/diatom.jpg
This phylum of algae is noted for its symmetry and beautiful glass shells – used in toothpaste!!!
Red algae:
www.alumni.ca/ ~thoga3n/redalgae.gif faculty.clintoncc.suny.edu/
faculty/Michael.Gr...
* The red pigment, phycoerythrin, allows red algae to photosynthesize at greater depths
* The agar in the plates that we used for the bacteria lab was a red algae
* Carrageenan (an ingredient in many ice creams) and Nori (the wrapping around sushi) are both red algaes
Nori: red algae used for makisushi
Brown algae; you guessed it, its brown!
http://www.nmnh.si.edu/botany/projects/algae/Imag-Pha.htmhttp://www.sonoma.edu/biology/algae/Nereocystis.GIF
The largest living algae; kelp forms an underwater forest-like habitat.
Characteristics in Common
•All form delicate, netlike structures on the surface of their food source
•Obtain energy by decomposing organic material (externally; release enzymes to break down food and then absorb).
Slime molds
• Slime molds obtain food through decomposition of organic material
• This is a slime mold> commonly found on grass. It’s called the dog vomit slime mold – eewww, gross!
Plasmodial Slime Molds•Form plasmodiumplasmodium: a mass of cytoplasm that contains many diploid nuclei but no cell walls or membranes – its feeding stageits feeding stage
•Creeps by amoeboid movement – 2.5 cm/hour
Plasmodial slime molds continued…
•May reach more than a meter in diameter
•Form reproductive structures when surroundings dry up
•SporesSpores are dispersed by the wind and grow into new plasmodium
Cellular Slime Molds•In feeding mode, they exist as individual amoebic like cells
•When food becomes scarce, they come together with thousands of their own kind to reproduce
•May look like a plasmodium
Water Molds and Downy Mildews
•Live in water or moist places•Feed on dead organisms or parasitize plants
•Fuzzy white growths•Caused the great Irish Potato Famine!!
Matching Part 1:On a separate sheet of paper, match each numbered
statement with the correct lettered organism (some used twice). Answers are on the next slide.
1. Pretty glass shells
2. Huge kelp beds
3. Lead to red tides
4. Causes African Sleeping Sickness
5. Sushi wrap
6. One type is “dog vomit”
7. Has flagella and chloroplasts
8. Have 2 flagella
9. Decompose their food
10. Causes malaria
11. Ancestors of land plants
12. Can photosynthesize at great depths
a. Dinoflagellates
b. Trypanasoma
c. Slime molds
d. Diatoms
e. Red algae
f. Brown algae
g. Green algae
h. Euglena
i. Plasmodium
Matching practice: Answers on next page
a. Dinoflagellates g. phaeophytab. Trypanasoma h. green algaec. Slime molds i. red algaed. Diatoms j. Euglenae. Paramecium k. Plasmodiumf. Giardia l. rhizopoda
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5 6 7 8
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