BIOL 1030 – TOPIC 2 LECTURE NOTESTopic 2: Protists (Kingdom Protista – Ch. 28)I. Kingdom ProtistaA. General characteristics1. most diverse kingdom in domain Eukarya2. some are unicellular, some are colonial, and some are truly multicellular3. only artificial grouping among kingdoms (paraphyletic at best)4. essentially all eukaryotes that are not plants, not animals, and not fungi5. kingdom is in the process of being abandoned6. classification in state of flux, revision ongoing- here I will use essentially the phyla given in your lab manual, with some additions and groupings- note that your lab manual leaves out some of the groups that will be covered hereB. There appear to be eight major lineages of within Eukarya1. this is very similar to the groupings give in your textbook, but updated based on more recent consilience between molecular and morphological evidence2. each lineage contains at least some organisms traditionally placed in kingdom Protista3. these lineages are not generally given a formal taxonomic level; instead they are simply unranked taxons (distinct lineages) often called “supergroups”; however, sometimes some of these are called “superphyla” or even kingdomsC. The lineages, in order starting with those that appear to be most distantly related to humans: these 8 supergroups are the new subset to the domain Eukarya, so no more protists1. Excavata2. Discicristata3. Alveolata4. Stramenopila5. Rhizaria6. Archaeplastida (includes traditional kingdom Plantae)7. Amoebozoa8. Opisthokonta (includes traditional kingdoms Fungi and Animalia)II. ExcavataA. synapomorphies1. pronounced “feeding groove” excavated area on the cell membrane 2. no functioning mitochondria (changed and involved in other things but no aerobic respiration like humans), although 1 of 6BIOL 1030 – TOPIC 2 LECTURE NOTESnucleus has some genes derived from mitochondriaB. two major group, Diplomonads and ParabasalidsC. Diplomonads1. “double cell” structure2. have two equal-sized nuclei and multiple flagella3. modified mitochondria called mitosomes4. includes Giardia lamblia, the organism that causes “hiker’s diarrhea” or giardiasis-infects humans and some other animals; found across U.S. in most freshwater-causes nausea, cramps, diarrheaD. Parabasalids1. modified mitochondria called hydrogenosomes that make hydrogen gas2. includes Trichomanas vaginalis, a sexually transmitted parasite in humans- disease called trichomoniasis or “trich” infections- over 7 million new infections each year in the U.S. alone, although many show no symptoms- symptoms are discolored discharges from vagina or penis and painful urination and intercourse- most infected men and about 20% of infected women have no obvious symptomsIII. DiscicristataA. synapomorphy: mitochondria with distinctive disc-shaped cristaeB. largest group is the phylum Euglenozoa (1 group you have to remember)C. Phylum Euglenozoa (euglenids and kinetoplastids) is the largest group within this clade1. crystalline or spiral rod in flagella 2. euglenids- some photosynthetic (using chlorophylls a and b, like green algae and plants), but some are not- ancestors of photosynthetic forms likely got their chloroplasts from green algae that they ate (“secondary endosymbiosis”) – in other words, this is NOT a synapomorphy that defines a clade (ate a functional chloroplast)- some are facultative heterotrophs, photosynthetic forms that can switch to being heterotrophs if kept in the dark, and switch back to autotrophs if given enough light- characterized by having a helical, flexible protein coat called a pellicle on the outside of cell no cell wall- only asexual reproduction- important members of many freshwater food chains- example: Euglena.3. kinetoplastids- single, large mitochondrion that has an organized mass of DNA called a kinetoplast - include trypanosomes – a group that includes some important parasites of humans and domestic animals African sleeping sickness: caused by Trypanosomai. carried to new host by biting fly (tsetse fly)ii. Affects cattle and prevents livestock culture in large area of Africa.Leishmaniasis (caused by Leishmania)i. carried to new host by biting fly (sand fly) in tropical areasii. causes sores and erosion of skin (4 million people/yr)IV. Alveolata (all three phylum shown as a polytomy)A. synapomorphy: sac-like “alveoli” that form a continuous layer just under the plasma membraneB. 3 major groups1. Phylum Dinoflagellata (dinoflagellates)2. Phylum Apicomplexa (sporozoans)3. Phylum Ciliophora (ciliates)C. Phylum Dinoflagellata (dinoflagellates)1. unicellular, mostly marine; 2100 species known2. usually have 2 flagella3. most have chlorophylls a and c, so chloroplasts are like those of diatoms, golden algae, and brown algae, more likely dueto secondary endosymbiosis4. have an exoskeleton made up of plates of cellulose have cell wall5. reproduce mostly by asexual reproduction (sex rare but it does occur)6. important/interesting roles: zooxanthellae: symbionts just living together: not mutualistic unless both sides are benefiting (live in mutually beneficial relationship) in other organisms (jellyfish, sea anemones, mollusks, corals) 2 of 6BIOL 1030 – TOPIC 2 LECTURE NOTES zooxanthellae in corals (up to 30,000 cells per cubic mm or coral tissue) do photosynthesis and make carbon products absorbed by coral help make coral reefs one of most productive habitats on Earth can actually leave the corals and live on their own – probably in response to pollution many of the world’s coral reefs are bleaching (dinoflagellates are leaving), killing the coral- bioluminescent: many planktonic dinoflagellates emit light when disturbed creates sparkling waves and glowing wakes of ships at night ww submarines Why do this? Perhaps to attract predatory fish to eat the predators of the dinoflagellates!- predatory dinoflagellates some generate toxins that they use to kill marine life example, Pfiesteria piscicida: stuns fish with toxin and feeds on body fluids red tides: population explosions (“blooms”) that can color the water with pigmented dinoflagellate cells; red tides kill marine life due to the high concentration of toxins from the dinoflagellates some dinoflagellates cause disease in humans who are exposed to them in high levels hog farm manure lagoons in NC appear to be a breeding ground for deadly dinoflagellates that cause freshwater fish kills and human