1. Kingdom Protista

2. The Link Between Bacteria and the Multicellular World
There are plant-like protists that photosynthesize
Dinoflagellates
Euglena
Diatoms
Algae

3. The Link Between Bacteria and the Multicellular World
Some are carnivorous protists that are hunters
Amoebas
Ciliates

4. The Link Between Bacteria and the Multicellular World
Finally, some are like fungus, because they absorb nutrients from the surroundings and produce spores.
Slime molds.

5. Protist: Characteristics
All are Eukaryotic
Some motile, some not
Some single-celled, some multicellular.
Variety of Ways to Get Energy
Some are
Carnivorous
Photosynthetic
Chemoautotrophic
Detritivores

6. Characteristics Reproduction Primarily Asexual
Budding
Fragmentation
Spores
Sexual (less common but does happen)
Many events happen in times of stress
Male + Female gametes
Sometimes, protists

7. Protista: General Characteristics

8. Classification and Phylogeny
diplomonads
Flagellated Protozoans
parabasalids
trypanosomes
euglenoids
radiolarians
foraminiferans
prokaryotic ancestor
ciliates
Alveolates
dinoflagellates
apicomplexans
water molds
diatoms
Stramenopiles
brown algae
Figure 22.2
Single-celled protists include (a) amoebas, (b) euglenoids, and (c) diatoms. Most red algae (d) and all brown algae (e) are multicelled. (f) One proposed eukaryotic family tree with traditional protist groups indicated by tan boxes. Notice that the protists are not united as a single lineage.
Figure It Out: Are land plants more closely related to the red algae or the brown algae?
Answer: red algae
red algae
chlorophyte algae
Green Algae
charophyte algae
land plants
amoebas
Amoebozoans
slime molds
fungi
choanoflagellates
animals

9. Group: Flagellated Protozoans
Flagellated protozoans are single-celled protists covered by a pellicle (proteins that help cells retain shape)
They swim in lakes, seas, and the body fluids of animals
They are typically heterotrophic and reproduce asexually by binary fission

10. Trypanosomes and Other Kinetoplastids
Kinetoplastids are flagellated protozoans with a single large mitochondrion
Trypanosomes include human pathogens that are transmitted by insects
African sleeping sickness (T. brucei) is spread by tsetse flies
Chagas disease (T. cruzi) is spread by bloodsucking bugs

11. Human Disease Trypanosoma African sleeping sickness
Transmitted by tsetse fly
Causes fever, mental deterioration and coma

12. Phylum Zoomastigina
No means of locomotion- most are parasitic and don’t need it
Sexual reproduction present
Environment- parasitic-aquatic

13. Human Disease Giardia Causes giardiasis
Sever diarrhea and intestinal cramps
Parasite in contaminated water
Thousands of cases annually in U.S.
Not usually fatal, but, you can imagine, uncomfortable.
                               
A SEM micrograph of the small intestine of a gerbil infested with Giardia reveals a mucosa surface almost entirely obscured by attached trophozoites

14. The Euglenoids
Euglenoids are flagellated protists related to kinetoplastids that do not infect humans
Most prey on bacteria
Some have chloroplasts that evolved from green algae and can detect light with an eyespot
Most live in freshwater and have contractile vacuoles that expel excess water

15. Foraminiferans & Radiolarians
Heterotrophic single cells with chalky or glassy shells live in great numbers in the world’s oceans; cytoplasm extends through many pores.
Most forams live on the seafloor; others drift as part of the plankton.

16. Phylum Actinopoda Radiolarians Silica test
Pseudopodia used for food getting
Asexual reproduction
Mostly marine

17. Phylum Foraminifera Forams Locomotion and food getting by pseudopodia
Calcium carbonate test
Environment- primarily marine

18. Group: Alveolates/ Ciliates
Ciliates are heterotrophic single cells that move about with the help of cilia
Ciliates reproduce asexually by binary fission or sexually by conjugation.

19. Phylum Ciliophora Locomotion and food getting by cilia
Pellicle present maintains shape
Contractile vacuoles remove excess water
Sexual reproduction by conjugation
Environment- aquatic
Heterotrophic & parasitic

20. Paramecium Unicellular Heterotrophic Cilia Requires oxygen to live
= aerobic environment
Asexual & Sexual Reproduction
Special Quality
2 nucleii
Found in most aquatic environments

21. Phylum Ciliophora Stentor Largest freshwater protozoan Can regenerate
body parts
Cilia covers body
for movement &
feeding

22. This organism is aggressive and has a huge appetite
Phylum Ciliophora
Didinium
This organism is aggressive and has a huge appetite

23. Didinium feeding Attaches to paramecium Starts to ingest
Almost completely engulfed

24. Phylum Apicomplexa Protozoan that causes malaria
Plasmodium enters bloodstream, travels to liver cells, where they divide and release new spores into the bloodstream.
Parasitic
No locomotion
Reproduce asexually
Transmitted by bite of infected mosquito
Destroys red blood cells
                               

25. Group: Stramenopiles “Red Algae”
Brown algae are multi-celled protists that live in temperate or cool seas; ranging from microscopic filaments to giant kelp
Some brown algae are used commercially
Thickeners (algins), food, fertilizer, herbal supplements (bladderwrack)

26. Diatoms
Diatoms are single-celled or colonial protists that have a two-part silica shell
Shells accumulate on the seafloor (diatomaceous earth)
Most are photosynthetic, with a brown accessory pigment (fucoxanthin)
Major components of phytoplankton

27. Group: Red Algae
Red algae are mostly multi-celled marine algae that live in clear, warm waters
Red accessory pigments (phycobilins) allow red algae to live at greater depths than other algae
Red and green algae share a common ancestor with chloroplasts derived from cyanobacteria
Life cycles vary and are often complex, with both asexual and sexual phases; there is no flagellated stage.

28. Group: Green Algae Most green algae are chlorophytes
Chlorella: Single celled, grown as health food
Chlamydomonas: Single celled, freshwater alga
Volvox: Colonial, freshwater alga
Cladophora: Forms long filaments
Ulva: “Sea lettuce”
Codium fragilis: Branching marine alga
Charophyte algae include several lineages that form a clade with land plants
Desmids: A single-celled, freshwater group
Spirogyra: Forms long filaments
Stoneworts (Chara): Closely related to land plants

29. Group: Amoebozoans
Amoebozoans send out pseudopods, move about, and capture food
Most have no cell walls, shell, or pellicles
Amoebas live as single cells
Example: Amoeba proteus, a freshwater predator
Slime molds are “social amoebas”
Plasmodial and cellular slime molds
Plasmodial slime molds spend most of their lives as a plasmodium
A streaming multinucleated mass that feeds on microbes and organic matter
Undergoes mitosis many times without cell division
Develops into spore-bearing fruiting bodies

30. Phylum: Sarcodina Amoebas Unicellular
Have pseudopodia = “false foot” which is an extension of the cytoplasm
Pseudopodia for locomotion & feeding
Reproduce asexually
Most are free-living, some parasitic
Found in soil, marine and freshwater
Amoebas

31. Amoeba Structure

32. Amoeba locomotion & feeding
Endocytosis (Phagocytosis)
Digestion by enzymes
Distinguish between food and non-food

33. Recap
Protists represent the kingdom where evolutionary adaptations allowed for the development of plants, fungus, and animals from single-celled bacteria.
Protists have numerous characteristics that allow for grouping.
Some protists are good for us: provide nutrients, photosynthesize, etc.
Some protists cause disease: malaria, African sleeping sickness, giardiasis.