MMG 301 1nd Edition Lecture 3Outline of Last Lecture I. MicroscopesOutline of Current Lecture II. Microbial diversityIII. Physiologic diversity IV. Early EarthV. Hypothesis for the origin of lifeCurrent Lecture-facts about microbial diversity and abundance-microbes outnumber all other species and make up ~60% of the earth’s biomass-microbes drive the chemistry of life and affect the global climate -microbial cycling of chemical elements helps keep the world inhabitable-microbes generate at least half the oxygen we breathe -microbes thrive in extreme environments-500 to 1,000 species of bacteria live in the human gut-there are at least 10 times more bacteria as human cells in the body-less than 0.5% of the estimated 2-3 billion microbial species have been identified-physiologic diversity of microorganisms-chemotrophs-chemoorganotrophs: organic molecules-chemolithotrophs: inorganic chemicals-phototrophsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-anoxygenic: do not produce oxygen-oxygenic: produce oxygen-carbon-autotrophs: use CO2 as a sole source of carbon-heterotrophs: use preformed organic carbon molecules as carbon source-oxygen-strict aerobes: only grow in the presence of O2-strict anaerobes: only grow in the absence of O2-facultative anaerobes: can grow in the presence or absence of O2-evidence for microbial life on early earth -isotopic carbon ratios-stromatolites: fossilized microbial malts-microbial fossils in ancient rocks-subsurface hypothesis for the origin of life-life arose in hot, oxygen free environment-most likely on the ocean floor-evidence: present day hyperthermophiles in deep sea
View Full Document
Unlocking...