Q+A: 2:30-#:20 pm in 404E (instead of office hours on Monday)TODAY- Eukaryotes: Domain 3- 4 Kingdoms- Protists + FungiA surveyPlease work through all slides after classAbout 2.1 billion years ago:Where did eukaryotes come from?- Endosymbiont theory: Lynn Margulis; could only be tested in 1980s; published in 1981  “Symbiosis in Cell Evolution”- Required reading: Zimmer 2008Q1: From which domain(s) did these endosymbionts (internal symbionts) originally come from?A Bacteria B Archae C Bacteria & Archae D EukaryotesEndosymbiosis: one organism takes in second organism- Probably started with endocytosis (gets closer and closer until larger cell engulfs smaller cell)- For it to be possible, smaller cell can’t be digested- Variation time for digestion; if ingested organism has benefit (metabolism) selection for delayed digestion- Synchronize cell division of both cells  inherit/reproduceMost common endosymbionts: mitochondria & chloroplasts- Cyanobacteria (bacteria)  chloroplasts- Purple bacteria (bacteria)  mitochondriaOriginal cell was probably archae; endosymbionts were probably bacteriaEukaryotes were the product of this processEndosymbiosis is very common- Like Russian dolls: one inside the other- During evolutionary history: secondary endosymbiosis leads to plastid diversity- During individual development: endosymbiosis between corals and algae (zooxanthellae)The Tree of Life with Horizontal Gene TransferDomain EukaryaEvolution of Eukarotes4 Eukaryotic Kingdoms: Protists, Plants, Animals, Fungi“Verken process”: work in processA new proposal for eukaryotic “supergroups”I. Protists: A Survey- Harmful (human perspective)o Giardia (intestinal distress)o Trypanosoma (sleeping sickness)o Plasmodium (malaria)o Dinoflaggelates (e.q. Pfiesteria: fish kills)- Beneficial (all do photosynthesis)o Dinoflaggelateso Diatoms (glass-like silica wallso Foraminifera (calcium carbonate)  chalko Laminaria (brown algae; kelp)o Porphyra (red algae)o Volvox (green algae)Case Study: Red Tide- Dinoflagellates- Plankton = all organism that drift in water column- Can be autotroph or heterotroph- Most phytoplankton serve as energy producers and base of food web - Small number of species produce potent neurotoxins that can be transferred through food webCase Study: Red Algae- Found in ocean b/c need salt water - Ocean farming to be used in sushi- Steep land so they have to do agriculture in the ocean- Source of nori, agar (used in labs for petri dishes), carrageenan (used in low fat foods)Animals, plants, & fungi have evolved from Protist ancestorsWhich are the closest relatives of Plants?A Fungi B Animals C Chlorophytes D CHarophytesProtists and Plantae- Closest relatives to plantae: charophytes )and other green algae)Protists and Animalia- Closest realtives to Animalia: choanoflagellatesProtists and Fungi & AnimaliaClosest relative to Fungi and Animalia & Choanoflagellates: Amoebozoa (slime molds)Case Study: Slime molds- Closest relatives to Fungi & AnimaliaIndividual cells will form a colony  form stalks out of colonies  stalks continue to growLook at Cityostelium animations (link on eLC)II. Fungi: A Survey- Mushrooms: talking about sexual reproductive functions; tends to happen when food sources get limited, before they disperse- Why not asexual instead of sexual? Sexual varies genetics by reshuffling alleles; more diverse individuals will increase chances of survival in different environments- Sexual reproduction is unique for eukaryotesEvolution of Fungi- Fossil fungus ~460 MYA- About 1.5 bya: split of fungi and animal/choanoflagellate lineages (unicellular ancestors with flagellum)- Long cells: Sa/V ratio- Sphere has minimum surface you can have; any change with same volume increases SAFungi Characteristics- Heterotrophs by absorptiono Decomposers, symbionts (e.g. mutualists, parasites)- Cell walls contain chitin- Fungal body consists of mycelia (branched network of hyphae)- Sexual life cycle- Asexual reproductionInsects have chitin on outside of body; fungi have chitin in cell wallsBacteria: peptidoglycan & plants: celluloseDifference between frogs and insectsHuge number of insectsFrogs: Live in wet humid environmentsFrogs: wet skin; water-permeable skinInsects: no water-permeable skin; can live in dry environmentsMajor groups of fungi:- Chitrids: infect things like frogso Oldest fungal groupo Many primitive traitso Some lack true hyphae (only spherical cell)o Many aquatic (fresh water)o Degrade chitin and keratin (way they make a living)o Have flagellated spores (aquatic life style)o More at risk of dessecating due to being water-permeableo Some are pathogenso May have contributed to extinction of several frog species- Zygomyceteso Infect strawberries, bread, dungo Hyphae absorb nutrientso Zygosporangium (sexual dispersal and survival stageo Pilobolus sporangia on cow dung: sensing light (to aim spores)o Stalks to help get above surface in order to disperse farther- Glomeromyceteso Partners in arbuscular mycorrhizaeo Hyphae invade plant root cells to form haustoria o Don’t penetrate plant cell membraneo Mutual exchange of nutrientso Fungus: suga; plants: water & minerals- Ascomycetes (sac fungi)o Unicellular: yeastso Multicellular Sexual reproduction in asci (sacs) Asexual reproduction Penicillium (mold) Moerls, truffelso Lichens (symbiosis): mutualism between fungi and cyanobacteria OR green algae 40% of ascomycetes are lichen