1. Kingdom Protista

2. 12.Discuss the rationale for taxonomic reorganization of the kingdom protista 13.Contrast the use of taxonomic “supergroups” with the traditional approach to classifying protists 14.Identify characteristics used to distinguish groups of protists. Give some common examples 15.Identify the protistans most closely associated with Fungi, Plants, and Animals

3. Dating back to the 2 kingdom approach to taxonomy, some protists (“protozoa”) were classified with animals due to their ability to move, where other protists (“algae”) were classified as plants due to their ability to photosynthesize Following that logic, the protozoa were further subdivided based on their means of locomotion, while the algae were largely categorized by their photosynthetic pigments

4. Ciliates – use cilia Flagellates – use flagellae Amoeboids – use pseudopodia Sporozoans – have no means of locomotion

5. Cilia Relatively short and densely distributed over the surface of the cell

6. Flagellae Longer and less numerous than cilia, but practically identical in internal structure

7. Internal structure consists largely of bundles of microtubules in a “9+2” arrangement 9 pairs in a circular arrangement with 2 in the middle

8. http://www.youtube.com/watch?v=QGAm6hMysTA

9. Pseudopodia Literally “false feet” Extensions of the cytoplasm used not only for movement but also for feeding

10. http://www.youtube.com/watch?v=pvOz4V699gk http://www.youtube.com/watch?v=TOPMaNvGTvc http://www.youtube.com/watch?v=d_Bkg8euB5Y

11. Non-motile All of these types are parasitic and rely on a “vector” for movement to a new host

12. Different frequencies of light penetrate water differently, so red, yellow and brown pigments allow photosynthesis in deeper water, where green is restricted to shallower water Blue-green Algae - actually prokaryotic cyanobacteria Golden Algae – contain yellow and brown carotenoids Yellow Algae (diatoms) have silaceous cell walls Red Algae – contain phycoerythrin. Some are multicellular (note “nori” used to wrap sushi) Brown Algae – contain brown and olive colored carotenoids. All are multicellular (note “kelp”) Green Algae – c0ntain chlorophyll A and B and have cell walls made of cellulose

13. The phylogenic approach to taxonomy demands that organisms are classified based on real ancestral divergences, and that the characteristics we use to distinguish the taxa are Homologous, not Analagous (“homoplasy”, or “homoplastic” in some textbooks) Characteristics are homologous if they are derived from a common ancestry, even if they are modified to adapt to different functions or circumstances, or even diminished to the point of lacking a function (vestigial) Analagous traits or structures are superficially similar, but evolved independently

14. Modern technology in biochemistry and electron microscopy reveals patterns impossible to observe by scientists of earlier generations Many traits traditionally used for protist taxonomy are actually analagous. Photosynthesis has evolved independently in several lineages, as have pseudopodia for locomotion. In some lineages ancestral characters have diminished significantly, concealing the relationship between apparently distinct groups of organisms.

15. A number of cellular organelles appear to be derived from ancient endosymbiosis events. Organelles originating by endosymbiosis are recognized by several factors: One or more additional membranes Independent reproduction within the host cell DNA within the organelle itself (resembling bacterial DNA) These organelles are believed to be the result of endosymbiosis: Mitochondria Centrioles Plastids (Chloroplasts)

16. Primary Resulted from the engulfing of a prokaryotic cell which was retained as an organelle Mitochondria and centrioles are the result of primary endosymbiosis The chloroplasts of Red and Green Algae are primary endosymbionts Secondary Resulted from the engulfing of a primitive eukaryotic cell which was retained as an organelle. Simply, it is like an organelle with organelles of its own Chloroplasts of chromalveolates are secondary endosymbionts See page 577, figure 28.2

17. 1.Cite at least four examples of structural and functional diversity among protists 2.Summarize the role of endosymbiosis in eukaryotes

18. The supergroup approach eliminates the Kingdom Protista, and instead subdivides the Domain Eukarya into 5 ancestral lineages, each of which contains some members of the former Protist kingdom. 3 of the 5 supergroups contain only protists 1 of the supergroups includes the Plants and their closest protist relatives 1 of the supergroups contains both Animals and Fungi, and closely related protozoans

19. As endosymbiosis events created the cellular organizations we recognize as Eukaryotes, variations in these fundamental structures form the differences between the supergroups Variations in mitochondria, centrioles, cilia & flagellae, plastids and pseudopodia represent ancestral characters These variations are more difficult to recognize than characteristics traditionally used for classification, but appear to be the real result of common ancestry – so it’s better, but harder to grasp at our level of study

20. Have diminished mitochondria that can function anaerobically and flagellae with additional crystalline rods The name “excavate” comes from a groove (excavation) in the cell body Familiar excavates include: Euglenoids – “mixotrophic” flagellates that can photosynthesize, consume food by phagocytosis, and swim using flagella Trypanosomes – parasitic flagellates that cause African Sleeping Sickness

21. Appear to have originated as a result of a secondary endosymbiosis involving red algae Some have chloroplasts resembling red algae Some lack plastids, but have some residual DNA homologous to plastid DNA The chromalveolata are very diverse. One subtaxon consists of traditional protozoans : ciliates, sporozoans and dinoflagellates (which are photosynthetic). The other subtaxon consists of a variety of algae: diatoms, golden algae and brown algae as well as the “water molds” which superficially resemble fungi

22. #2.Would you expect the plastid DNA of photosynthetic dinoflagellates, diatoms, and golden algae to be more similar to the nuclear DNA of plants (Domain Eukarya) or to the chromosomal DNA of cyanobacteria (Domain Bacteria). Explain

23. Originally classified with the sarcodina (amoebae) due to the presence of pseudopodia DNA analysis shows these organisms to be distinct from the amoebae Pseudopodia in the Rhizaria are threadlike, rather than lobe shaped Many have a cell wall or exoskeleton made of calcified organic material (the foraminiferans) or silica (the radiolarians) Some also have flagellae, and may even be photosynthetic

24. As implied by the “plastida” suffix, these organisms share a similar chloroplast structure. The chloroplasts of these organisms originates from an ancient endosymbiosis with a cyanobacterium This supergroup includes the red algae, green algae, and Kingdom Plantae The plants appear to be descended from an ancestral green alga

25. #1.Contrast Red algae and Brown algae #2.Why is it accurate to say that Ulva is truly multicellular but Caulerpa is not? #3.Suggest a possible reason why species in the green algae lineage may have been more likely to colonize land than species in the red algae lineage

26. Unikonts include Kingdom Animalia, Kingdom Fungi, and their closest protozoan relatives Unikonta is divided into 2 subtaxa, the Amoebozoa and the Opisthokonta The Amoebozoa include the familiar amoebae (those with lobe shaped pseudopodia) and the slime molds The Opisthokonta include the Kindgom Fungi, the Choanoflagellate protists, and the Kingdom Animalia The animals appear to be descended from a choanoflagellate ancestor

27. #1.Contrast the pseudopodia of amoebozoans and forams

28. Start individually and progress to small group (3) Construct a matching set using the 5 supergroups as choices. Write 10 questions based on examples, structural features, etc. Quiz the other members of your small group Condense your question set and quiz a second group The second group will also quiz your group. Do page 599 #1-6 and #8