Prokaryotes and “Kingdom Protista”

1. Prokaryotes and “Kingdom Protista”

2. Domain bacteria Domain Archae The Prokaryotes

3. Cell type: Prokaryotes • Found in: • Domain Bacteria • Domain Archaebacteria

4. Cell type: Prokaryotes • Two Domains: Bacteria and Archae • Do not have a membrane bound nucleus • Very few organelles, if any • Smallest and structurally simplest living organisms. • Oldest forms of life on earth • Microscopic • Circular shaped DNA molecules • Shapes: rod, spherical or spiral

5. Metabolism • Autotrophic -photosynthetic -chemosynthetic • Heterotrophic -aerobic respiration (with oxygen) -anaerobic respiration (without oxygen) ex: use SO4-2 instead of oxygen (Anoxic: environment without oxygen)

6. Domain Bacteria • Unicellular; some form colonies. • Cell wall of peptidoglycan • Essential role in nutrient cycles • Major groups: decay bacteria, cyanobacteria, nitrifying bacteria, pathogenic bacteria

7. Domain Bacteria: Decay Bacteria • Break down waste products and detritus • Detritus: dead organic matter • Release nutrients into the environment • Importance: recycling of essential nutrients

8. Domain Bacteria: Cyanobacteria • Also known as blue-green algae • Photosynthetic • Photosynthetic Pigments -Contains chlorophyll a (pigment in plants) -Phycocyanin: bluish pigment -Phycoerythrin: reddish pigment -Dominant pigment determines color

9. Domain Bacteria: Cyanobacteria • Stromatolites: Thought to have an important role in the accumulation of oxygen in earth’s atmosphere • Prochlorococcus: thought to be most abundant photosynthetic organism in the ocean • Red tides: bloom of cyanobacteria with red pigment (can cause skin rashes)

10. Prochlorococcus

11. Oscillatoria

12. Spirulina and Oscillatoria

13. Anabaena

14. Domain Bacteria: Nitrifying Bacteria • Carry out nitrogen fixation -converting nitrogen gas into ammonium which is then converted into nitrates.

15. Domain Archae • Used to be classified with Bacteria but are now thought to be closer related to eukaryotes. • Extremophiles: found in extreme environments (acid pools, hot springs, hydrothermal vents, etc…) • Methanopyrus: methanogen living near hydrothermal vents • Common throughout the ocean not just extreme environments

16. Domain Eukarya“Kingdom Protista” The Eukaryotes

17. Cell type: Eukaryotes • Have a membrane bound nucleus and complex organelles. • Found in Domain Eukarya • Includes Kingdoms: “Protista,” Fungi, Plantae, Animalia

18. “Kingdom Protista” • Domain Eukarya • So diverse a kingdom, that many scientists don’t consider it a true kingdom anymore • Divided into two general groups: • Algae: plant-like protists. • Protozoans: animal-like protists.

19. Characteristics of Algae (plant-like protists) • Eukaryotic (nucleus!) • Can be unicellular or multicellular • Mostly photosynthetic (have chloroplast) • Contain cell walls (many different kinds) • a.k.a. phytoplankton • Our Focus now: unicellular (i.e. single cell)

20. DIATOMS Phylum Bascillariophyta Algae (plant-like protists) • “golden algae” • carotenoid pigments (such as xanthophyll = yellow pigment) • chlorophyll a and c • Classified according to shape • Centricae: round • Pennatae: pen-shaped • Buoyancy • Need to float near the surface to absorb sunlight • Adaptations to help prevent sinking by decreasing density: • Radiating spines • Oil droplets (lipids)

21. DIATOMS Phylum Bascillariophyta Algae (plant-like protists) • Cell Wall • made of silica (main ingredient of glass). • Has tiny pores to allow for exchange of materials. • Also called frustule or test.

23. Diatoms

24. DIATOMS Phylum Bascillariophyta Algae (plant-like protists) • Reproduction • Asexual: fission; two frustules separate and each half secretes a new frustule to complete the formation of the new diatom. • Sexual: diatom develops into a male or female. Male releases sperm and enter the female diatom where it unites with an egg. The fertilized egg develops into a mature diatom.

27. DIATOMS Phylum Bascillariophyta Algae (plant-like protists) • Blooms • Occur in favorable conditions such as adequate nutrition and light • Normally spring and fall due to overturn (upwellings) • Some contain a toxin called domoic acid that can build up in plankton eating organisms Both shellfish and fish can accumulate this toxin without apparent ill effects; however, in humans the toxin crosses into the brain and interferes with nerve signal transmission. People poisoned with very high doses of the toxin can die, while lower doses can cause permanent brain damage (short term memory loss).

28. DIATOMS Phylum Bascillariophyta Algae (plant-like protists) • Diatomaceous Earth • Dead diatom frustules fall to ocean floor • Form a thick deposit of siliceous material • Biogenous sediment: a.k.a. diatomaceous ooze • Used in many industries; good for filtering (swimming pools, drinking water, clarifying beer) and a good mild abrasive (toothpaste and polishers)

29. DIATOMS Phylum Bascillariophyta Algae (plant-like protists) • Ecological Importance • Basis of the food chain in both marine and freshwater environments • Consumed by tiny invertebrates called copepods who are eaten by fish • Shellfish consume diatoms by filtering them out of the water

30. DINOFLAGELLATES Phylum Dinophyta Algae (plant-like protists) • Unicellular • Planktonic • Two flagella • Cell wall made of plates of cellulose • Autotrophic and heterotrophic • Eyespot: detect light

32. DINOFLAGELLATES Phylum Dinophyta Algae (plant-like protists) • Flagella • Used in locomotion • One trails free • One wrapped around a groove along the middle of the cell

35. DINOFLAGELLATES Phylum Dinophyta Algae (plant-like protists) • Reproduction and Blooms • Almost exclusively asexual (fission) • Red Tide: caused by Gymnodinium (contains a red pigment) • Gonyaulax: produces a neurotoxin that causes paralytic shellfish poisoning that can lead to illness and death in fish and humans.

36. Red Tide (Gymnodinium)

38. Gymnodinium

39. DINOFLAGELLATES Phylum Dinophyta Algae (plant-like protists) • Some are bioluminescent :produces light (Pyrodinium) • Zooxanthellae: round, golden brown dinoflagellates that live in close association with a variety of animals • Sponges • Corals • Sea anemones • Giant clams

40. Bioluminescent Dinoflagellate

41. Characteristics of Protozoans (animal-like protists) • Animal-like • Structurally simple and very diverse • Most are unicellular • Heterotrophs • Some are also photosynthetic • Marine and freshwater as well as inside other organisms

42. FORMANIFERANSPhylum Granuloreticulsa Protozoans (animal-like protists) • Called forams • Marine • Have tests (shells) of calcium carbonate (CaCO3) • Pseudopodia: extension of cytoplasm that protrude through pores; trap food • Benthic or planktonic

43. Protozoans (animal-like protists)

44. Foraminiferan Ooze Protozoans (animal-like protists) • Calcareous ooze • Create limestone and chalk beds • Biogenous ooze

45. Protozoans (animal-like protists)

46. RADIOLARIANSPhylum Polycystina Protozoans (animal-like protists) • Planktonic, marine • Delicate shells of silica with radiating spines • Needle-like pseudopodia that capture food • Radiolarian ooze

47. Protozoans (animal-like protists)

48. Protozoans (animal-like protists)

49. CILIATESPhylum Ciliophora Protozoans (animal-like protists) • Protozoans with cilia • Cilia: hair-like and used in locomotion and feeding • Planktonic or benthic • Live on the gills of clams, intestines of sea urchins or on the skin of fish • Paramecium: most common freshwater forms

50. Protozoans (animal-like protists)