1. How are Protists related to other eukaryotes?
What is a Protist?
How are Protists related to other eukaryotes?

2. Does everyone agree how to classify protists?
No, at present, biologists do not agree how to classify protists
The amount of diversity among the protists, is much greater than within or between the other three eukaryotic kingdoms

3. The Protist Dilemma
Protists are grouped together solely because they are not fungi, plants or animals
Furthermore, many protists are more closely related to members of other eukaryotic kingdoms than they are to other protists.

4. Current Protist classification
It has been proposed that the protista kingdom be divided into six groups or clades
Today, while we still use the term Protist, this is not a single kingdom, but a collection of organisms in six clades

5. What is a Protist? A protist is a eukaryote (has a nucleus)
A protist is any eukaryote that is not a plant, animal or fungus

6. Evolution of Protista Endosymbiont Hypothesis

7. Are all protists unicellular?
No, although most are unicellular, some protists are colonial, and some like the giant kelp are multicellular.
Unicellular Colonial
Multicellular

8. How do Protists Move? Some move with flagella
Long whip-like projections
One to two per cell
Examples
Trypanosoma
Euglena
Trypanosoma

9. Euglena
Two flagella
No cell wall
Chloroplasts

10. How do Protists move? Some move with cilia
Cilia can be used for feeding and movement
Cilia are short and used like oars on a boat
Example
Paramecium

11. Ciliates - Paramecium Go to Section: Trichocysts Oral groove Lysosomes
Anal pore
Gullet
Oral groove
Trichocysts
Lysosomes
Food vacuoles
Contractile vacuole
Micronucleus
Macronucleus
Cilia
Go to Section:

12. Some do not move
Those that do not move produce spores and live as parasites
Plasmodium causes malaria
Cryptosporidium spreads through contaminated drinking water and caused intestinal disease

13. Excavates: feeding groove, flagella
Diplomonads
Giardia is an intestinal parasite that causes cramping and diarrhea
Discicristates
Euglena is free living and can use its chloroplast for photosynthesis or can live as a heterotroph
Trypansoma causes African sleeping sickness; carried by tsetse flies

14. Euglena Go to Section: Chloroplast Carbohydrate storage bodies Gullet
Pellicle
Contractile vacuole
Flagella
Eyespot
Nucleus
Go to Section:

15. Chromalveolates: very diverse group; most are photosynthetic
Phaeophytes = multicellular brown algae
Chrysophytes = unicellular golden algae
Diatoms = unicellular algae with intricate silicon dioxide (silica) shells
Ciliates = paramecium are not photosynthetic
Dinoflagellates = half are photosynthetic, half are heterotrophs; some are luminescent
Apicomplexans = parasitic Plasmodium

16. Brown algae Phaeophytes Photosynthetic Chlorophylls a and c
Brown accessory pigment fucoxanthin
Multicellular
Giant kelp, Fucus

17. Photosynthetic protists
Chrysophytes
“Golden plants”
Gold-colored chloroplasts
Cell walls contain pectin instead of cellulose
Store food as oil rather than starch
Can form thread like colonies

18. Photosynthetic protists
Diatoms
Glass like cell walls
Cell walls contain silicon (Si)
Cell walls like petri dish

19. Photosynthetic protists
Dinoflagellates
Luminescent
“Fire plants”
Half photosynthetic
Half heterotrophs
Two flagella

20. Apicomplexan Plasmodium
Mosquito borne parasites like the species that causes malaria

21. Cercozoa, Foraminiferan, Radiolarian
Have pseudopods
Many produce protective shells
Foraminiferans
Heliozoan

22. Rhodophytes Red Algae Chlorophyll a Red accessory pigment – phycobilin
Absorbs blue light
Grows very deep
Multicellular
Nori

23. Ecology of photosynthetic protists
Base of the food chain
Half of the photosynthesis on earth is carried out by phytoplankton

24. Ecology of photosynthetic protists
Algal blooms
Caused by too much pollution or nutrients
Deplete water of oxygen
Kill fish and invertebrates
Dinoflagellates cause “red tides”
Red tides produce toxins which can be taken in by shellfish. Eating these shellfish can cause illness, paralysis and death

25. Green algae Phylum Chlorophyta
Same chlorophyll and cell wall composition as green plants
Chlorophyll a and b
Store food as starch
Found in fresh and salt water and on land
Unicellular, colonial and multicellular
Now classified with plants

26. Unicellular green algae
Chlamydomonas
Lives in ponds, ditches and wet soil
Egg shaped
Two flagella
Large, cup-shaped chloroplast

27. Colonial green algae Spirogyra Volvox Filamentous
Forms threadlike colonies
Spiral chloroplasts
Volvox
Hollow spheres
500 – 50,000 identical cells
Some cell specialization

28. Human uses of algae Oxygen
Food (nori; thickening agent (carrageenan) in ice cream, egg nog, chocolate, salad dressing)
Industry (plastics, waxes, paints, lubricants)
Science labs (agar)

29. Alternation of generation – alternating between diploid and haploid organisms
Diploid – having two copies of each chromosome
Haploid – having one copy of each chromosome
Gametophyte – haploid gamete producing organism
Sporophyte – diploid spore producing organism

30. Heterotrophic protists
Amoebozoa = Amoebas use pseudopods for movement and feeding
Ciliates = Paramecia use cilia to move food to gullet; food vacuoles and lysosomes digest the food; waste is released through the anal pore
Slime Molds and Water Molds absorb food through their cell walls from dead or decaying matter; decomposers

31. An Amoeba Section 20-2 Go to Section: Contractile vacuole Pseudopods
Food vacuole
Nucleus
Contractile vacuole
Pseudopods
Go to Section:

32. Slime molds

33. Slime molds

34. Water molds Cells are multinucleate Cell walls of cellulose
White fuzz on dead fish in water
Plant parasites on land
Cause potato blight responsible for potato famine

35. Reproduction in water molds
Can produce sexually and asexually
Motile (swimming) spores
Antheridium produces sperm
Oogonium produces eggs

36. Mutualistic relationships
Zooxanthellae – live inside coral and provide food through photosynthesis
Trychonympha – live in the gut of termites and digest cellulose