1. Chapter 28: Protists - structure, function, diversity, evolution, impact
Protists (Chapter 28)
1. More structural and functional diversity than any other group of organisms…
2. Most are unicellular, some colonial and multicellular…
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
3. Most nutritionally diverse eukaryotes
A. photoautotrophs
B. heterotrophs
C. mixotrophs – combine photosyn with hetertrophic nutrition

2. Chapter 28: Protists - structure, function, diversity, evolution, impact
Broken into three general categories based on ecological context:
1. Photosynthetic (plant-like) protists
- algae
2. Ingestive (animal-like) protists
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
- protozoans
3. Absorptive (fungus-like) protists

3. Chapter 28: Protists - structure, function, diversity, evolution, impact
How did such incredible diversity arise?
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Many species resulted from two rounds of endosymbiosis…

4. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Phylogenetic tree showing the major clades of protists.

5. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
What’s a clade?
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
A complete branch of a phylogenetic tree. Above how many clades are highlighted?
Two, the blue and the red because these are complete branches. The green is not complete.

6. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Let’s examine a handful of these clades…

7. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Euglenozoa
Fig. 28.8
Characterized by spiral or crystalline rod within flagella in addition to 9+2 arrangement of microtubules.
African trypanosomiasis symptoms occur in two stages. The first stage is known as the haemolymphatic phase and is characterized by fever, headaches, joint pains, and itching. Invasion of the circulatory and lymphatic system by the parasites is associated with severe swelling of lymph nodes, often to tremendous sizes. Winterbottom's sign, the tell-tale swollen lymph nodes along the back of the neck, may appear. If left untreated, the disease overcomes the host's defenses and can cause more extensive damage, broadening symptoms to include anemia, endocrine, cardiac, and kidney dysfunctions. The second stage, called the neurological phase, begins when the parasite invades the central nervous system by passing through the blood-brain barrier. The term 'sleeping sickness' comes from the symptoms of the neurological phase. The symptoms include confusion, reduced coordination, and disruption of the sleep cycle, with bouts of fatigue punctuated with manic periods leading to daytime slumber and night-time insomnia[citation needed]. Without treatment, the disease is invariably fatal, with progressive mental deterioration leading to coma and death. Damage caused in the neurological phase is irreversible.[6]
Tryptophol is a chemical compound that induces sleep in humans. It is produced by the trypanosomal parasite in sleeping sickness.[7]
Cyrstalline structure has unknown function.

8. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Euglenozoa
Fig. 28.8
African trypanosomiasis symptoms occur in two stages. The first stage is known as the haemolymphatic phase and is characterized by fever, headaches, joint pains, and itching. Invasion of the circulatory and lymphatic system by the parasites is associated with severe swelling of lymph nodes, often to tremendous sizes. Winterbottom's sign, the tell-tale swollen lymph nodes along the back of the neck, may appear. If left untreated, the disease overcomes the host's defenses and can cause more extensive damage, broadening symptoms to include anemia, endocrine, cardiac, and kidney dysfunctions. The second stage, called the neurological phase, begins when the parasite invades the central nervous system by passing through the blood-brain barrier. The term 'sleeping sickness' comes from the symptoms of the neurological phase. The symptoms include confusion, reduced coordination, and disruption of the sleep cycle, with bouts of fatigue punctuated with manic periods leading to daytime slumber and night-time insomnia[citation needed]. Without treatment, the disease is invariably fatal, with progressive mental deterioration leading to coma and death. Damage caused in the neurological phase is irreversible.[6]
Tryptophol is a chemical compound that induces sleep in humans. It is produced by the trypanosomal parasite in sleeping sickness.[7]
Phylum kinetoplastid
Ex. Genus Trypanosoma
- Causes sleeping sickness
- Spread by African tsetse fly
- Fatal if untreated
- Evade immune system by repeatedly changing the proteins on the surface of the cell

9. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Euglenozoa
Fig. 28.8
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Phylum euglenid
Ex. Euglena
- Found in freshwater
- Photoautotroph if sunlight available otherwise heterotroph by absorbing nutrients from environment (mixotroph)

10. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Let’s examine a handful of these clades…

11. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Alveolata
Fig. 28.8
Characterized by sacs below membrane called alveoli having yet unknown function
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]

12. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Alveolata
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Phylum dinoflagellates
- Abundant as both marine and freshwater phytoplankton
Phytoplankton – phyto = photosynthetic, plankton = “free-drifting”
- free-drifting photosynthetic organisms (cyanobacteria is also a large part of phytoplankton)
- Bloom (explosion of growth) can cause “red tide”
- Secrete toxins that bioaccumulate in molluscs making them dangerous to eat
- Have internal “plates” of cellulose giving its characteristic shape…

13. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Alveolata
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Phylum Ciliates
- Obviously use cilia to move and feed
Ex) Paramecium
Two types of nuclei
- Large (macro) nucleus
- Smaller (micro) nucleus
- Can have more than one of each

14. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Alveolata
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Phylum Ciliates
Macronucleus
- Contains dozens of copies of genome
- Genes are not on chromosomes (they don’t have chromosome)
- Arranged in small units each having many duplicates of a single gene
- The gene products (i.e. proteins) control daily functions like feeding, waste removal, etc…

15. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Alveolata
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Phylum Ciliates
Feeding
- Mainly on bacteria, which are moved through oral groove and phagocytosed at “cell mouth” into food vacuoles.
- Food vacuoles fuse with lysosomes
- Undigestable material is egested when lysosomes fuse with cell membrane

16. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Alveolata
Phylum Ciliates
Reproduction
- Mostly asexually by “binary fission”
Conjugation
- Genetic diversity, NOT REPRODUCTION
- two organisms exchange haploid micronuclei (see fig 28.12b above and use book for more detail)

17. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Let’s examine a handful of these clades…

18. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Stramenopila
Phylum Diatom (Bacillariophytes)
- Unicellular Algae
- glass-like silica based cell wall as shown in figure
- Protection from predators
- Withstand pressures up to 1.4 million kg/m2 (pressure applied by the leg of a table with an elephant standing upon it)

19. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Stramenopila
Phylum Diatom (Bacillariophytes)
Reproduction
- Usually asexually by mitosis
- Sexual reproduction is not common, but does occur
Diversity
- Estimated 100,000 species
- Major component of phytoplankton in oceans and lakes

20. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Stramenopila
Phylum Golden Algae (chrysophytes)
(chrysos = golden)
Dinobryon
- Contain yellow/brown cartenoid pigments
- Freshwater and marine plankton
- All obviously photosynthetic, some species mixotrophs
- Most unicellular, but some, as shown, are colonial

21. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Stramenopila
Phylum Brown Algae (phaeophytes – guess what phaeo means…)
Kelp
- Largest and most complex algae (its what you call seaweed)
- All are multicellular and most are marine (salt water – ocean)
- Common along temperate costs like ours

22. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Stramenopila
Phylum Brown Algae
Sea palm (Postelsia)
Kelp
Thallus
- The body of the seaweed that is plant-like
- Basically, the holdfast, stipe (stem-like) and blades (leaf-like) (see above)
Holdfast
- root-like structure at base solely for anchoring, not absorption like roots of plants

23. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Stramenopila
Phylum Brown Algae
Life-cycle: Alternation of Generations
This is important to understand because as you might guess, since plants evolved from multicellular algae, they also do this.
Heteromorphic
- The two generations are structurally different as opposed to being isomorphic
Laminaria (a brown algae)

24. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Let’s examine a handful of these clades…

25. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Cercozoans and Radiolarians
- Amoeba with threadlike pseudopods
- Amoeba is a general term for a protist that uses pseudopodia to move and feed. There is no one clade or kingdom that consists of amoebas

26. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Cercozoans and Radiolarians
Foraminiferans (Forams)
Radiolarian
- Foramen means “little hole”
- Tests made of silica
- Named for porous shells called tests
- Pseudopodia called axopodia
- Organic molecules hardened with CaCO3
- Pseudopodia extend through pores of shell and fx in test formation, swimming and feeding
Both of these phyla consist of amoebas because…

27. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Let’s examine a handful of these clades…

28. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Amoebozoans
- Amoeba with lobe shaped rather than threadlike pseudopods belong to this clade:
Now this amoeba belongs to the above kingdom…

29. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Amoebozoans
Phyla: Gymnamoeba
Phagocytosis of a ciliate:

30. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Amoebozoans
Phyla: Slime Molds (mycetozoans)
Were once thought to be fungus hence the name, but molecular evidence has revealed convergent evolution
Two major types:
1. Plasmodial Slime Molds
2. Cellular Slime Molds
They in part by their life cycles…

31. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Amoebozoans
Phyla: Slime Molds (mycetozoans)
Plasmodial Slime Mold Life Cycle

32. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Amoebozoans
Phyla: Slime Molds (mycetozoans)
Cellular Slime Mold Life Cycle

33. Chapter 28: Protists - structure, function, diversity, evolution, impact
Phylogeny of protists
Fig. 28.4
applying a primary stain (crystal violet) to a heat-fixed (death by heat) smear of a bacterial culture
the addition of a trapping agent (Gram's iodine)
rapid decolorization with alcohol or acetone, and
counterstaining with safranin.[8] carbol fuchsin is sometimes substituted for safranin since it will more intensely stain anaerobic bacteria but it is much less commonly employed as a counterstain.[9]
Let’s examine a handful of these clades…

34. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Rhodophyta
Rhodo = red
Red Algae
Red due to pigment known as phycoerythrin, which masks chlorophyll
Most large and multicellular, living in tropical waters
Alternation of Generations

35. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Chlorophyta
Chloro = green
Green Algae
Much like plants, systematics has shown close relationship b/w green algae and plants as you would expect…
Two groups
- Chlorophytes and Charophyceans
1. Chlorophytes
- More than 7,000 species, most in fresh water
- Simplest are unicellular
- These are the ones that live in mutualism with fungus to form lichen
Watermelon snow showing the incredible diversity of chlorophytes
*Charophyceans and most related to land plants and are discussed at beginning of Ch. 29 with plants

36. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Chlorophyta
Chloro = green
Green Algae
Larger size and complexity arose via:
1. Colony formation (ex. Volvox) and multicellular filament formation.
2. Repeated division of nuclei without cytoplasmic division (ex. Caulerpa)
3. True multicellular forms with cell division and differentiation (Ex. Ulva)

37. Chapter 28: Protists - structure, function, diversity, evolution, impact
Kingdom Chlorophyta
Syngamy = fusion of gametes, aka fertilization/conception
Chloro = green
Green Algae
Complicated life cycle of asexual and sexual stages:

38. Chapter 28: Protists - structure, function, diversity, evolution, impact