BIOL2610: Prokaryotes and Protists PDF

BIOL2610: Biodiversity, Ecology, and Evolution Prokaryotes and Protists Hierarchy of naming living things: Scientific names: The genus name is capitalized, the species name is on small case. The name is either capitalized or in italics. Homo sapiens, Drosophila neot...

BIOL2610: Biodiversity, Ecology, and Evolution Prokaryotes and Protists Hierarchy of naming living things: Scientific names: The genus name is capitalized, the species name is on small case. The name is either capitalized or in italics. Homo sapiens, Drosophila neotestacea Prokaryotes: ancient organisms single cells no nuclear membrane in domains Bacteria and Archaea prokaryotes circled in blue: Page 1 of 3 Prokaryotes were abundant ≈ 3.5 mbillion years ago. First fossils. Prokaryotes are small single celled organisms. YET, the total biomass of prokaryotes in the world is more than the total biomass of eukaryotes. Three kinds of Prokaryotes are described by their shape: 1. Cocci, means grapes in Greek- are little round cells, streptococci that causes strep throat is an example. 2. Bacilli, are rod-shaped (like E. coli). 3. Spirochetes, spiral-shaped. The bacteria that cause syphilis and Lyme disease are spirochetes. Diversity in processing nutrition: Energy Phototrophs – capture energy from sunlight Chemotrophs – capture energy from chemicals Carbon Autotrophs – get carbon from CO2 in the atmosphere Heterotrophs – get carbon by eating other organisms Prokaryotes: Bacteria. - Very Diverse Group of Organisms. A. Proteobacteria. may be a plant symbiont like Rhizobium- Plant root with nodules are created by the bacteria Rhizobium. Rhizobium fix atmospheric N2 which the plant uses. may be a plant pathogen – various plant rots are caused by bacteria. May cause human disease: LOTS of them. Salmonella sp. = food poisoning Vibrio cholarae = cholera May help humans: Escherichia coli: helps us digest food. Sometimes “good” bacteria turn “bad”. “O157:H7” = strain of E. coli. 75,000 cases in U.S. since 1980s. 60% led to death. DNA sequence: 20% of genome not in other E. coli genomes. Some bacteria eat other bacteria: B. Spirochetes Helical bacteria that cause many human diseases. Syphilis Lyme Disease C. Gram-Positive Bacteria Streptomyces: soil dwelling bacteria. Cultured by pharmaceutical companies. Inhibits growth of other bacteria. Important in controlling Tuberculosis. Page 2 of 3 D. Cyanobacteria Can generate oxygen like plants! The first fossils were created by cyanobacteria. VERY important in changing the earth’s atmosphere from anaerobic (no oxygen) to on with oxygen (aerobic). Prokaryotes: Archaea. Archaea are abundant in many habitats, including places where few other organisms survive. EXTREME HALOPHILES = “salt lovers” – live in places with high salt concentrations – Salt Lake in Utah or the Dead Sea. EXTREME THERMOPHILES = “heat lovers” life in hot springs and deep sea vents. METHANOGENS = live in anaerobic environments. Live in the bottom of swamps, do not need oxygen, produce methane (CH4). Page 3 of 3