Features of Kingdom Protista

1. Features of Kingdom Protista • All members have eukaryotic cells. • Individual life cycles vary considerably, but reproduction is generally by cell division and sexual processes. • Most multicellular members produce some motile cells.

2. Outline • Phylum Chlorophyta • Phylum Chromophyta • Phylum Rhodophyta • Phylum Euglenophyta • Phylum Dinophyta • Phylum Cryptophyta • Phylum Prymnesiophyta • Phylum Charophyta • Phylum Myxomycota • Phylum Dictyosteliomycota • Phylum Oomycota

3. Phylum Chlorophyta • The Green Algae • Includes about 7,500 species that occur in a rich variety of forms and occur in diverse, widespread habitats. • Greatest variety found in freshwater lakes, ponds, and streams. • Most have a single nucleus. • Most reproduce both sexually and asexually.

4. Fig. 18.2

5. Green Algae: • contain pigments (chl a & b) similar to higher plants. • store food in the form of starch within their chloroplasts.

6. Phylum Chlorophyta • Chlamydomonas • Common inhabitant of freshwater pools. • Pair of whip-like flagella on one end pull the cell through the water. • Single, cup-shaped chloroplast with one or two pyrenoids inside. • Pyrenoids = Proteinaceous structures thought to contain starch synthesis enzymes.

7. Chlamydomonas

8. Chlamydomonas • Asexual Reproduction • Nucleus divides by mitosis, and cell contents become two daughter cells within the cellulose wall. • Develop flagella and swim away.

9. Sexual Life Cycle of Chlamydomonas

10. Phylum Chlorophyta • Ulothrix • Thread-like alga. • Single row of cylindrical cells forming a filament. • Basal cell functions as a holdfast.

11. Ulothrix Life Cycle

12. Phylum Chlorophyta • Spirogyra (Watersilk) • Common freshwater algae consisting of unbranched filaments of cylindrical cells. • Frequently float in masses at the surface of quiet waters. • Asexual Reproduction • Fragmentation of existing filaments. • Sexual Reproduction • Papillae fuse and form conjugation tubes.

13. Spirogyra Sexual Reproduction

14. Phylum Chlorophyta • Oedogonium • Epiphytic filamentous green alga. • Each cell contains a large, netlike chloroplast that rolls and forms a tube around and toward the periphery of each protoplast.

16. Phylum Chlorophyta • Other Green Algae • Chorella - Widespread green alga composed of tiny spherical cells. • Reproduce by forming either daughter cells or autospores through mitosis. • Desmids - Mostly free-floating and unicellular. • Reproduce by conjugation.

17. Fig. 18.8

18. Phylum Chlorophyta • Other Green Algae • Hydrodictyon (Water Nets) - Net-like, tubular colonies with hexagonal or polygonal meshes. • Asexual reproduction as well as isogamous sexual reproduction. • Volvox - Colonial green algae held together in a secretion of gelatinous material • Reproduction asexual or sexual.

19. Fig. 18.9

20. Fig. 18.10

21. Phylum Chlorophyta • Other Green Algae • Ulva (Sea Lettuce)- Multicellular seaweed with flattened green blades. • Isomorphic reproductive structures. • Cladophora - Branched, filamentous green alga with species represented in both fresh and marine waters. • Mostly multinucleate.

22. Fig. 18.11

23. Phylum Chromophyta • The Diatoms (Bacillariophyceae) • Among best known and economically most important members of this phylum. • Mostly unicellular • Occur in both fresh and salt water. • Particularly abundant in colder marine habitats.

24. Fig. 18.14

25. Reproduction in Diatoms

26. Phylum Chromophyta • The Brown Algae (Phaeophyceae) • Relatively Large • Most Marine • Non-Unicellular or Colonial • Many have a thallus differentiated into a holdfast, a stipe, and blades. • Blades may have gas-filled bladders. • Sargassum - Floating Brown Seaweed • Fucus - Common Rockweed

27. Brown Alga Nereocystis

28. Fig. 18.16

29. Fig. 18.18

31. Phylum Rhodophyta • The Red Algae • Most species are seaweed. • Tend to occur in warmer and deeper waters than brown algae. • Most are filamentous. • Relatively complex life cycle involving three types of thallus structures. • Colors mostly due to phycobilins. • Numbers of species produce agar.

32. Fig. 18.21

33. Phylum Euglenophyta • The Euglenoids • Spindle-shaped. • No cell wall, thus changes shape as it moves. • Sub-membrane strips and membrane form pellicle. • Contains gullet. • Contains red eyespot. • Reproduction by cell division.

34. Fig. 18.23

36. Phylum Dinophyta • The Dinoflagellates • Unicellular • Contain two flagella. • One trails behind the cell. • Other encircles the cell at right angles. • Most have disc-shaped chloroplasts. • Contain xanthophyll pigments. • Many have tiny projectiles. • Many types of toxins produced. (Red Tides)

37. Dinoflagellates

38. Human and Ecological Relevance of Algae • Diatoms • Oils are sources of vitamins. • Diatomaceous Earth • Filtration • Polishes • Reflectorized Paint • Other Algae • Chlorella • Potential human food source.

39. Human and Ecological Relevance Algae • Algin • Produced by giant kelp. • Ice Cream, Salad Dressing • Latex Paint, Textiles, Ceramics • Agar • Produced by red alga Gelidium. • Solidifier of nutrient culture media for growth of bacteria.

40. Table 18.2

41. Phylum Myxomycota • The Plasmodial Slime Molds • Totally without chlorophyll and are incapable of producing their own food. • Distinctly animal-like during much of life cycle, but fungus-like during reproduction. • Plasmodium converts into separate small sporangia (each containing spores) during times of significant environmental changes.

42. Fig. 18.30

43. Fig. 18.31

44. Phylum Dictyosteliomycota • The Cellular Slime Molds • About two dozen species of cellular slime molds are not closely related to the other slime molds. • Individual amoebalike cells feed independently, dividing and producing separate new cells periodically. • Human and Ecological Relevance • Break down organic particles to simpler substances.

45. Fig. 18.33

46. Phylum Oomycota • The Water Molds • Often found on dead insects. • Range in form from single spherical cells to branching, threadlike, coenocytic hyphae. • Coenocytic hyphae may form large thread masses(mycelia).