1. Chapter 15 Kingdom Protista Lecture Outline
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2. Outline Introduction Features of Kingdom Protista Algae
Phylum Chlorophyta – The Green Algae
Phylum Chromophyta – The Yellow-Green Algae, Golden-Brown Algae, Diatoms, and Brown Algae
Phylum Rhodophyta – The Red Algae
Phylum Euglenophyta – The Euglenoids
Phylum Dinophyta – The Dinoflagellates
Phylum Cryptophyta – The Cryptomonads
Phylum Prymnesiophyta (Haptophyta) – The Haptophytes
Phylum Charophyta – The Stoneworts
Human and Ecological Relevance of the Algae
Phylum Myxomycota – The Plasmodial Slime Molds
Phylum Dictyosteliomycota – The Cellular Slime Molds
Phylum Oomycota – The Water Molds

3. Introduction
Less than 1 billion years ago, organisms confined to oceans.
Protected from drying out, ultraviolet radiation, and large fluctuations in temperature
Absorbed nutrients directly from water
About 400 million years ago, green algae began making transition from water to land.
Gave rise to green plants
Coleochaete probably indirect ancestor of land plants.
Shares features with land plants: cells that resemble parenchyma, development of cell plate and phragmoplast during mitosis, a protective covering for zygote, and production of lignin-like compound
Coleochaete

4. Features of Kingdom Protista
Domain Eukarya - All members have eukaryotic cells.
Includes Kingdoms: Protista, Plantae, Fungi, Animalia
Organisms in Protista vary from unicellular to multicellular.
Nutrition varied: photosynthetic, ingestion of food, absorption of food
Individual life cycles vary considerably.
Reproduction generally by cell division and sexual processes.
Algae are in Kingdom Protista.
Grouped into several phyla based on form of reproductive cells, and combinations of pigments and food reserves.

5. Phylum Chlorophyta Green algae
Unicellular, filamentous, platelike colonies, netlike tubes, hollow spheres, lettuce-like leaves
Greatest variety in freshwater lakes, ponds, and streams
Some on tree bark, in animal fur, in snowbanks, in flatworms or sponges, on rocks, in lichen “partnerships.”
Have chlorophylls a and b
Store food as starch
Most have a single nucleus per cell.
Most reproduce both sexually and asexually.

6. Phylum Chlorophyta Chlamydomonas Common inhabitant of freshwater pools
Unicellular
Pair of whip-like flagella on one end pull cell through water.
Two or more vacuoles at base of flagella
Regulate water content of cell and remove waste
Single, cup-shaped chloroplast with one or two pyrenoids inside
Pyrenoids - Proteinaceous structures associated with synthesis of starch
Red eyespot near base of flagella
Allows alga to swim toward light

7. Phylum Chlorophyta Chlamydomonas Asexual reproduction:
Nucleus divides by mitosis, and cell contents become two daughter cells within cellulose wall.
Each develop flagella and swim away.
No change in chromosome number; all cells remain haploid.

8. Phylum Chlorophyta Chlamydomonas sexual reproduction:
Meiosis occurs in zygospore, producing 4 haploid zoospores that grow into full-sized algae.
Under certain conditions, cells congregate together.
Two cells fuse together to form zygote, that will become zygospore and may remain dormant.

9. Phylum Chlorophyta Ulothrix Filamentous with holdfast cell at one end
Chloroplast - Wide, curved, somewhat flattened, with one to several pyrenoids
Asexual reproduction:
Cells contents condense, divide by mitosis and become zoospores inside parent cell.
Zoospores escape through pore in parent cell wall.
Resemble Chlamydomonas cells
Grow into new filaments

10. Phylum Chlorophyta Ulothrix sexual reproduction:
Cell contents condense and divide by mitosis inside parent cell.
Each new cell produces flagella.
Cells escape from parent cell and become gametes.

11. Phylum Chlorophyta Spirogyra (watersilk)
Filaments of cylindrical cells
Frequently floats in masses on surface of quiet freshwater
Chloroplast ribbon-shaped and spirally wrapped around vacuole, with pyrenoids at regular intervals.
Asexual reproduction:
Only by fragmentation of filament

12. Phylum Chlorophyta Spirogyra (watersilk)
Sexual reproduction by conjugation.
Papillae fuse and form conjugation tubes.
Condensed protoplast of one filament flows or crawls through tube to adjacent cell.
Protoplasts fuse, forming zygote that develops thick wall.
Eventually zygote undergoes meiosis.

13. Phylum Chlorophyta Oedogonium
Epiphytic filamentous green alga with holdfast
Large netlike chloroplast with pyrenoids at intersections of net
Asexual reproduction:
By fragmentation or by zoospores
Zoospores produced singly in cells at tips of filaments.
Have about 120 flagella that form fringe toward one end of zoospore

14. Phylum Chlorophyta Oedogonium sexual reproduction:
Exhibits oogamy - One gamete is motile, while other is larger and stationary.
Antheridium - Boxlike cell that produces two motile sperm
Oogonium - Swollen cell containing single egg
Sperm enters oogonium through pore.
Zygote forms thick walls and may remain dormant.
Zygote produces 4 zoospores by meiosis that grow into new haploid filaments.

15. Phylum Chlorophyta Other green algae
Chlorella - Widespread green alga composed of tiny spherical cells
Only reproduce asexually by forming either daughter cells or autospores through mitosis
Used in research; may become important as food source
Desmids - Mostly free-floating and unicellular
Reproduce by conjugation
Closterium, a desmid

16. 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
Isogamous = two flagellated gametes

17. Phylum Chlorophyta Other green algae
Acetabularia (mermaid’s wineglass) - Consists of a single, huge cell shaped like a delicate mushroom
Used in classic experiments demonstrating influence of nucleus on form of cell
Isogamous

18. Phylum Chlorophyta Other green algae
Volvox - Colonial green algae held together in a secretion of gelatinous material, resembling hollow ball
Reproduction asexual or sexual
Smaller daughter colonies formed inside parent colony

19. Phylum Chlorophyta Other green algae
Ulva (sea lettuce) - Multicellular seaweed with flattened green blades and basal holdfast to anchor blades to rocks
Haploid and diploid blades
Diploid blades produce spores that develop into haploid blades.
Haploid blades bear gametangia that form gametes.
Gametes fuse to form zygotes that grow into diploid blades.
Exhibit isomorphism - Haploid and diploid blades indistinguishable.

20. Phylum Chromophyta Yellow-green algae (Xanthophyceae)
Mostly freshwater, with a few marine and terrestrial representatives
Two flagella of motile cells are oriented in opposite directions.
Vaucheria - Oogamous, coenocytic, filamentous species
Aplanospores formed during asexual reproduction.
Sexual reproduction rare.
Stipitococcus, a yellow-green algae
Sexual reproduction in Vaucheria

21. Phylum Chromophyta Golden-brown algae (Chrysophyceae)
Most occur in the plankton of fresh water.
Motile cells have two flagella of unequal length inserted at right angles to each other.
Photoreceptor on short flagellum.

22. Phylum Chromophyta The Diatoms (Bacillariophyceae) Unicellular
Fresh and salt water, particularly abundant in cold marine habitats
Also, dominate algal flora on damp cliffs, tree bark or buildings
Look like ornate, glass boxes with lids
As much as 95% of wall is silica.
Chlorophylls a and c and fucoxanthin
Food reserves - Oil, fats or laminarin

23. Phylum Chromophyta The Diatoms (Bacillariophyceae)
Asexual reproduction results in half of cells becoming progressively smaller.
Original cell size restored through sexual reproduction.

24. Phylum Chromophyta Brown algae (Phaeophyceae)
Relatively large; none unicellular or colonial
Most marine; majority in cold, shallow water, except giant kelp
Many have a thallus differentiated into a holdfast, a stipe, and blades.
Blades may have gas-filled bladders.
Chlorophylls a and c, fucoxanthin
Food reserve = laminarin
Algin in cell walls.
Nereocystis, a kelp

25. Phylum Chromophyta Brown algae (Phaeophyceae)
Sargassum - Floating brown seaweed
Asexual reproduction by fragmentation or autospores.
Sargassum

26. Phylum Chromophyta Brown algae (Phaeophyceae) Fucus - Common rockweed
Sexual reproduction:
Receptacles at tips of branches contain spherical chambers called conceptacles with gametangia inside.
Oogonium produces 8 eggs.
Antheridium produces 64 sperm.
Eggs and sperm released into water.

27. Phylum Rhodophyta The red algae
In warmer and deeper waters than brown algae
Most are filamentous with filaments so tightly packed they appear to have flattened blades or branched segments.
New photos

28. Phylum Rhodophyta The red algae
Relatively complex life cycle involving three types of thallus structures
Nonmotile reproductive cells

29. Phylum Rhodophyta The red algae Colors mostly due to phycobilins.
Similar to those of cyanobacteria
Red algae may have been derived from cyanobacteria.
Chlorophylls a, and sometimes d
Food reserve - Floridean starch
Numbers of species produce agar.

30. Phylum Euglenophyta The Euglenoids
No cell wall; pellicle = plasma membrane and underlying strips that spiral around cell
Flagellum pulls cell through water.
Gullet ingests food.
About 1/3 of species have disc-shaped chloroplasts.
Red eyespot for light detection
Paramylon food reserve
Asexual reproduction by cell division.
Sexual reproduction not confirmed.
New Photo

31. Phylum Dinophyta The Dinoflagellates
Red tides - Sudden multiplication of dinoflagellates
Some produce neurotoxins that accumulate in shell fish.
Cellulose “armor plates” inside cell membrane
Two flagella in intersecting grooves
One trails behind cell - Acts as rudder
Other encircles cell at right angles - Gives cell spinning motion

32. Phylum Dinophyta The Dinoflagellates
Most have disc-shaped chloroplasts.
Contain xanthophyll pigments
Chlorophylls a and c
About 45% nonphotosynthetic
Chromosomes remain condensed and visible throughout life of cell.
Starch food reserve
Many have tiny projectiles that fire when irritated.

33. Phylum Cryptophyta The Cryptomonads Marine and freshwater Two flagella
Plates on inside of plasma membrane
Single, two-lobed chloroplast with starch granules surrounding a central pyrenoid
Nucleomorph - Vestigial nucleus of primitive symbiotic organism
Gullet lined with ejectosomes.
Sexual reproduction unknown.

34. Phylum Prymnesiophyta (Haptophyta)
The Haptophytes
Fresh and saltwater; major component of marine plankton
Most unicellular, with two smooth flagella of similar length inserted at the apex.
Pigments and food reserve similar to Chromophyta.
Haptonema - Third flagellum located between two flagella.
Aids in food capture
Often covered in scales
Two disc-shaped chloroplasts

35. Phylum Charophyta The Stoneworts Shallow, freshwater lakes and ponds
Often precipitate calcium salts on their surfaces
Axis with short lateral branches in whorls.
Sexual reproduction is oogamous.
Multicellular antheridia

36. Human and Ecological Relevance of Algae
Protistan algal phyla at bottom of food chain.
Diatoms
Oils are sources of vitamins.
Diatomaceous earth
Filtration
Polishes, toothpaste
Paint that reflects light
Other algae
Chlorella
Potential human food source

37. Human and Ecological Relevance of Algae
Algin
Produced by giant kelps and other brown algae
Ice cream, salad dressing
Latex paint, textiles, ceramics
Regulates water behavior
Controls development of ice crystals
Regulates penetration of water
Stabilizes suspensions
Vessel harvesting kelp

38. Human and Ecological Relevance of Algae
Minerals and food
Iodine from kelp
Red algae
Food - Dulse, nori
Carrageenan - Thickening agent
Agar
Produced by red alga Gelidium
Solidifier of nutrient culture media
Retains moistness in bakery products
Base for cosmetics

39. Phylum Myxomycota The Plasmodial slime molds Without chlorophyll
Feed on bacteria and other organic particles
Consist of a plasmodium
Protoplasm containing many diploid nuclei
No cell wall
Flows rapidly and rhythmically
Found on damp forest debris, under logs, on dead organic material
Plasmodium

40. Sporangia from various plasmodial slime molds
Phylum Myxomycota
The Plasmodial slime molds
Sexual reproduction:
Plasmodium converts into separate small sporangia that contain spores.
Sporangia from various plasmodial slime molds

41. Phylum Myxomycota The Plasmodial slime molds Sexual reproduction:
Meiosis occurs in spores.
Spores grow into myxamoebae that act as gametes and fuse to form zygotes.
Zygotes grow into new plasmodia.

42. Phylum Dictyosteliomycota
The Cellular slime molds
Individual amoebalike cells feed independently, dividing and producing separate new cells periodically.
Clump together to form mass called pseudoplasmodium
Crawls like a garden slug
Eventually transforms into sporangium-like mass of spores
Human and ecological relevance of the slime molds:
Break down organic particles to simpler substances

43. Phylum Oomycota The Water molds
Cottony growths on fish; often found on dead insects
Range in form from single spherical cells to branching, threadlike, coenocytic hyphae
Coenocytic hyphae are not divided into individual cells and may form large thread masses (mycelia).
Share features with brown algae, including oogamy, cellulose in cell walls, predominantly diploid lifecycle, and zoospores with two flagella
Asexual reproduction:
Crosswalls form at tips of hyphae
Zoospores produced inside and emerge through pore.

44. Phylum Oomycota The Water molds Sexual reproduction:
Meiosis takes place in oogonia and antheridia.
Zygotes formed in oogonia give rise to new mycelia.
Human and ecological significance of the water molds:
Downy mildew on grapes
Potato blight
1846 famine in Ireland

45. Outline Introduction Features of Kingdom Protista Algae
Phylum Chlorophyta – The Green Algae
Phylum Chromophyta – The Yellow-Green Algae, Golden-Brown Algae, Diatoms, and Brown Algae
Phylum Rhodophyta – The Red Algae
Phylum Euglenophyta – The Euglenoids
Phylum Dinophyta – The Dinoflagellates
Phylum Cryptophyta – The Cryptomonads
Phylum Prymnesiophyta (Haptophyta) – The Haptophytes
Phylum Charophyta – The Stoneworts
Human and Ecological Relevance of the Algae
Phylum Myxomycota – The Plasmodial Slime Molds
Phylum Dictyosteliomycota – The Cellular Slime Molds
Phylum Oomycota – The Water Molds