1. Protists
Unit 6
Chapter 19

2. Protist characteristics
Eukaryotic: having organelles and nucleus
Unicellular or multicellular
Heterotrophic, autotrophic, or saprobic
Microscopic or large
Divided into three major groups: protozoans, algae, and fungus-like protists

3. Protozoans: animal-like protists
Heterotroph: consume organic matter
Unicellular

4. Algae: plant-like protists
Autotroph: uses light to make sugars through photosynthesis
Lack roots, stems, and leaves

5. Fungus-like protists Decompose dead matter
Motility during some stage of life cycle
No chitin in cell walls

6. Protist-borne diseases
Malaria
Sleeping sickness

7. Helpful protists
Algae through photosynthesis produce oxygen, that makes up the ozone layer.
Algae and protozoans can also be part of the plankton that feeds marine animals.
Fungus-like protists decompose matter and returns nutrients back to the soil.
plankton

8. Freshwater algae asexually reproducing
Protist reproduction
Mostly asexual: requiring one source of DNA for offspring
Sometimes sexual: requiring two sources of DNA for offspring
Freshwater algae asexually reproducing

9. Protozoans
Animal-like protists

10. Major groups of protozoans
Amoeba
Flagellate
Ciliate
Sporozoan

11. Movement with pseudopods
Pseudopod: “false foot”
Amoeba, shapeless cells

12. Feeding with pseudopods
The extensions of the cellular body surround food particles, which the amoeba then draws into itself for digestion.

13. Other amoeboid protozoans
foraminiferans
radiolarians

14. Movement with flagella
This disease causing Giardia protozoan has flagella to move around.

15. Flagellates whip their tails back and forth to propel the cell.

16. Movement with cilia
Note the fine cilia that surround the paramecium, making a “halo glow.”
Notice the starburst shaped organelle, the contractile vacuole that helps to pump out excess water.

17. Sporozoans: parasitic protozoans
Disease causing
Produces spores within host cell
Spore: reproductive cell that forms without fertilization and produces a new organism

18. Plasmodium, cause of malaria
The protist is transmitted through a mosquito bite to a human host.
The protist reproduces inside the human red blood cells, making them puckered and unable to carry oxygen to the body.

19. Malaria life cycle

20. Algae
Plant-like protists

21. Algae pigmentation All have chlorophyll
Some have other pigments: purple, rusty-red, olive-brown, yellow, and golden-brown.
Algae are grouped according to their pigmentation.
Ex: green algae

22. Major groups of algae Euglenoid Diatom Dinoflagellate Green algae
Red algae
Brown algae

23. Euglenoids Unicellular Aquatic Animal-like Plant-like: photosynthetic
No cell wall, just tough cell membrane
Flagella

24. Euglenoid

25. Diatoms: golden algae Shells made of silica (major component of glass)
Carotenoid pigment
Unicellular
Photosynthetic
Various shapes
Oily inside

26. Diatoms

27. Uses of diatoms, dredged from ocean floors
abrasives in tooth and metal polishes
added to paint to give the sparkle that makes pavement lines more visible at night

28. Dinoflagellates Many pigments Two flagella at grooves
Bioluminescent: emit light
Symbiotic relationship with jellyfish
Produce toxins

29. Red tide
Concentration of nerve toxins from certain dinoflagellates cause water bodies to appear red.
This water and contaminated shellfish can make humans sick.

30. Red algae Multicellular Commonly called seaweed
Thallus: Seaweed body that attaches to a surface
Found deep in the ocean because they can use the light that filters to the bottom for photosynthesis

31. Red algae

32. Brown algae Mostly multicellular Mostly in cool, marine waters
Air bladders in thallus keeps the algae floating

33. Kelp forests Habitat for many marine animals
Dense growth of brown algae
Habitat for many marine animals

34. Green algae Most diverse Chlorophyll-rich
Can grow anywhere, even in fur of sloth (below)
Colonial algae called Volvox

35. Unicellular green algae

36. Multicellular green algae

37. slime molds, water molds, and downy mildews
Fungus-like protists
slime molds, water molds, and downy mildews

38. Slime molds: most like true fungus
Cool, moist environments
Able to move around to feed during most of the life cycle
Two major types

39. Water molds and downy mildews
Fuzzy white growth on decaying matter

40. How water molds and downy mildews feed
They grow long extensions over the organic material and absorb nutrients through their cell membranes.
A particular species infected the Irish potato crop and caused a large famine.