Q A 2 30 20 pm in 404E instead of office hours on Monday TODAY Eukaryotes Domain 3 4 Kingdoms Protists Fungi A survey Please work through all slides after class About 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 2008 Q1 From which domain s did these endosymbionts internal symbionts originally come from A Bacteria B Archae C Bacteria Archae D Eukaryotes Endosymbiosis 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 reproduce Most common endosymbionts mitochondria chloroplasts Cyanobacteria bacteria chloroplasts Purple bacteria bacteria mitochondria Original cell was probably archae endosymbionts were probably bacteria Eukaryotes were the product of this process Endosymbiosis 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 Transfer Domain Eukarya Evolution of Eukarotes 4 Eukaryotic Kingdoms Protists Plants Animals Fungi Verken process work in process A 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 Dinoflaggelates o Diatoms glass like silica walls o Foraminifera calcium carbonate chalk o 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 web Case 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 ancestors Which are the closest relatives of Plants A Fungi B Animals C Chlorophytes D CHarophytes Protists and Plantae Closest relatives to plantae charophytes and other green algae Protists and Animalia Closest realtives to Animalia choanoflagellates Protists and Fungi Animalia Closest relative to Fungi and Animalia Choanoflagellates Amoebozoa slime molds Case Study Slime molds Closest relatives to Fungi Animalia Individual cells will form a colony form stalks out of colonies stalks continue to grow Look 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 eukaryotes Evolution 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 SA Fungi Characteristics Heterotrophs by absorption o Decomposers symbionts e g mutualists parasites Cell walls contain chitin Fungal body consists of mycelia branched network of hyphae Sexual life cycle Asexual reproduction Insects have chitin on outside of body fungi have chitin in cell walls Bacteria peptidoglycan plants cellulose Difference between frogs and insects Huge number of insects Frogs Live in wet humid environments Frogs wet skin water permeable skin Insects no water permeable skin can live in dry environments Major groups of fungi Chitrids infect things like frogs o Oldest fungal group o Many primitive traits o 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 permeable o Some are pathogens o May have contributed to extinction of several frog species Zygomycetes o Infect strawberries bread dung o Hyphae absorb nutrients o Zygosporangium sexual dispersal and survival stage o Pilobolus sporangia on cow dung sensing light to aim spores o Stalks to help get above surface in order to disperse farther Glomeromycetes o Partners in arbuscular mycorrhizae o Hyphae invade plant root cells to form haustoria o Don t penetrate plant cell membrane o Mutual exchange of nutrients o Fungus suga plants water minerals Ascomycetes sac fungi o Unicellular yeasts o Multicellular Sexual reproduction in asci sacs Asexual reproduction Penicillium mold Moerls truffels o Lichens symbiosis mutualism between fungi and cyanobacteria OR green algae 40 of ascomycetes are lichen partners