1. The Protists - Chapter 28 Lecture Objectives 1. Intro to “Protists”
2. Protist Classification
- Supergroups and Clades
3. Survey of Protists

2. Key Characteristics
1. Eukaryotic
2. Unicellular (mostly)  often colonial, or multicellular
3. Nutritionally Diverse
Photoautotrophs, Heterotrophs, Mixotrophs
4.Reproduction
Asexual (preferred) or Sexual
5. Worldwide distribution
Sensitive to changes in environment (water, sun, nutrients)
Rely on nutrients from ocean floor (upwelling)
* being altered by humans (runoff, global warming)

3. Dinoflagellates & coral polyps, wood-digesting in gut of termite
Key Characteristics con’t.
6. Importance
Symbionts
Dinoflagellates & coral polyps, wood-digesting in gut of termite
Plasmodium sp. (Malaria) , Phytophthora sp. (SOD, potato famine)
Producers
Along with prokaryotes  main producers in ocean * responsible for ~30% world’s photosynthesis

4. Prokaryotic producers
Other consumers
Herbivorous plankton
Carnivorous plankton
Figure Protists: key producers in aquatic communities
Prokaryotic producers
Protistan producers
Figure 28.29

5. Figure 28.28 Sudden oak death

6. Protist Classification
Polyphyletic group = current classification includes distantly related organisms, but does NOT include most recent common ancestors of all members
Kingdom “Protista” is no longer accepted  Grouped instead into what are called Supergroups (possible new kingdoms?)
Important to note this classification is still being sorted out and we will consider one hypothesis…….

7. 4 Supergroups & respective clades
Excavata
SAR
Archaeplastida
Unikonta

8. ■ Excavata ■ Archaeplastida ■ “SAR” Clade ■ Unikonta
5 μm
20 μm
50 μm
Diplomonads
Parabasalids
Excavata
Euglenozoans
Diatoms
Stramenopiles
Golden algae
■ “SAR” Clade
Brown algae
50 μm
■ Unikonta
Dinoflagellates
Apicomplexans
Alveolates
“SAR” clade
Ciliates
Forams
Cercozoans
Rhizarians
Radiolarians
100 μm
Red algae
Green algae
Chlorophytes
Charophytes
Archaeplastida
Giardia intestinalis, a diplomonad parasite
Globigerina, a rhizarian in the SAR clade
Land plants
100 μm
Slime molds
Amoebozoans
Tubulinids
Entamoebas
Nucleariids
Unikonta
Fungi
Opisthokonts
Choanoflagellates
Animals
Figure 28.2

9. Supergroup Excavata: - excavated “feeding” groove
- autotrophic or heterotrophic (predators)
Clade: Diplomonadida Clade: Parabasala Clade Euglenozoa sub clade: Kinetoplastida sub clade: Euglenophyta

10. SG: Excavata, Clade: Diplomonadida
Anaerobic
Simplified mitochondria  mitosomes
2 equal sized nuclei
Multiple Flagella
Ex. Giardia *Freshwater parasite in which cyst stage is consumed. Causes amoebic dysentery & killed by boiling water.
Giardia sp.

11. SG: Excavata, Clade: Parabasala
Anaerobic, lack true nuclei
Undulating membrane
Flagella
Modified mitochondria (release Hydrogen Peroxide)
 change in pH
 outcompete beneficial microorganisms
* Infection from gene transfer with prokaryote
* Ex. Trichomonas vaginalis
Trichomonas vaginalis

12. SG: Excavata, Clade Euglenozoa
Flagella w/ crystalline rod
Heterotrophs (predators), Autotrophic, Parasites, or Mixotrophs
“Sub Clades”
Kinetoplastida
* Cause of Sleeping Sickness vectored by Tsetse fly * Neurological disease which is fatal if not treated
Euglenophyta (see next slide)
Trypanosomes evade immune responses by switching surface proteins  host cannot develop immunity
Trypanasoma sp.

13. * Note 2 flagella Long flagellum Eyespot Light detector
Figure 28.8
* Note 2 flagella
Long flagellum
Eyespot
Light detector
Short flagellum
Contractile vacuole
Nucleus
Figure 28.8 Euglena, a euglenid commonly found in pond water
Chloroplast
Plasma membrane
5 μm
Pellicle: protein bands beneath PM
Euglena (LM)

14. Supergroup SAR Clade: Stramenopila – flagella with hair-like projections sub clade: Bacillariophyta
sub clade: Phaeophyta
sub clade: Chrysophyta Clade: Alveolata – Membrane bound sacs under PM sub clade: Dinoflagellata
sub clade: Apicomplexa
sub clade: Ciliophora Clade Rhizaria – Amoeba with thread-like pseudopods sub clade: Foraminifera sub clade: Radiolaria

15. Supergroup SAR, Clade Stramenopile = hairy flagella
Figure 28.9
Hairy flagellum
Smooth flagellum
Figure 28.9 Stramenopile flagella
5 μm
Supergroup SAR, Clade Stramenopile =
hairy flagella

16. SG: SAR, Clade: Stramenopila, sub-clade: Bacillariophyta
The Diatoms
Unicellular algae  phytoplankton
MOST abundant autotroph in oceans and lakes
Silica tests that overlap
Diatomaceous Earth
Help reduce C

17. SG: SAR, Clade: Stramenopila, sub-clade: Phaeophyta
Brown algae (fucoxanthin)
found in temperate coasts w/ cold water currents
Largest, most complex algae  multicellular
Tissues
Thallus (holdfast, stipe, blade)  analogous to plants
Waves & desiccation = cell wall with cellulose & algin
Alternation of Generations Lifecycle

18. Developing sporophyte Gameto- phytes (n)
Figure 28.13
Haploid (n)
Diploid (2n)
Sporangia
MEIOSIS
10 cm
Sporophyte (2n)
Zoospore
Female
Developing sporophyte
Gameto- phytes (n)
Figure The life cycle of the brown alga Laminaria: an example of alternation of generations
Zygote (2n)
Mature female gametophyte (n)
Egg
Male
FERTILIZATION
Sperm

19. SG: SAR, Clade: Stramenopila, sub-clade: Chrysophyta
Golden Algae
Unicellular, many colonial
Bi-flagellated
Fresh & marine phytoplankton, (some mixotrophs)
Yellow & brown pigments = xanthophyll
Microscopic & drift near surface of water
Protective cysts = decades

20. Supergroup SAR, Clade Alveolata = Alveoli (sacs under PM)
Figure 28.14
Flagellum
Alveoli
Alveolate
Figure Alveoli
0.2 μm
Supergroup SAR, Clade Alveolata =
Alveoli (sacs under PM)

21. SG: SAR, Clade: Alveolata, sub-clade: Dinoflagellata
“Dinoflagellates”
Marine & fresh phytoplankton
Mixotrophs or heterotrophs
Cellular plates of cellulose w/ grooves and 2 flagella
Red Tides

22. * May lead to mass mortalities
Figure 28.15
Flagella
(a) Dinoflagellate flagella
3 μm
* May lead to mass mortalities
Figure Dinoflagellates
(b) Red tide in the Gulf of Carpentaria in northern Australia

23. SG: SAR, Clade: Alveolata sub-clade: Apicomplexa
Apex on end of Merozoite
Internal parasites to animals
 Malaria
vectored by mosquito
 hides in cells where it is hidden from immune system
Africa, Asia, Latin America
 250 million infected, 900, die each year
Plasmodium sp.

24. Inside mosquito Inside human Merozoite Sporozoites (n) Liver
Figure 28.16
Inside mosquito
Inside human
Merozoite
Sporozoites (n)
Liver
Liver cell
Apex
Oocyst
MEIOSIS
Red blood cell
Merozoite (n)
0.5 μm
Red blood cells
Zygote (2n)
Figure The two-host life cycle of Plasmodium, the apicomplexan that causes malaria
Plasmodium requires both mosquitoes and humans to complete its life cycle
Approximately 900,000 people die each year from malaria
FERTILIZATION
Gametes
Game- tocytes (n)
Haploid (n)
Diploid (2n)

25. SG: SAR, Clade: Alveolata, sub-clade: Ciliophora
“Ciliates”
Cilia for locomotion & feeding
Macro & micro nuclei (sex)
Binary fission
Found in all waters
Predators or Parasitic
Paramecium sp.

26. (a) Feeding, waste removal, and water balance.
Figure 28.17a
Contractile vacuole
Oral groove
Cell mouth
Cilia
50 μm
Micronucleus
Food vacuoles
Macronucleus
Figure 28.17a Structure and function in the ciliate Paramecium caudatum (part 1)
(a) Feeding, waste removal, and water balance.

27. The original macro- nucleus disintegrates. Diploid micronucleus
Figure 28.17b-2
Compatible mates
Conjugation
Asexual reproduction
MEIOSIS
Haploid micronucleus
Diploid micronucleus
The original macro- nucleus disintegrates.
Diploid micronucleus
MICRO- NUCLEAR FUSION
Figure 28.17b-2 Structure and function in the ciliate Paramecium caudatum (part 2, step 2)
(b) Conjugation and reproduction.

28. SG: SAR, Clade: Rhizaria, sub-clade: Foraminifera
Marine, fresh water
Attached to sand, rocks, algae
Porous, multi-chambered shells (CaCO3) = tests
Pseudopods extend through pores
* Phagocytosis
Many have endosymbiotic algae
Mg content = temp changes
Make sedimentary rocks

29. SG: SAR, Clade: Rhizaria, sub-clade: Radiolarians
Delicate, symmetrical skeletons made of silica
Pseudopods radiate from central body  engulf via phagocytosis