BIOL 1108 Edition 1nd Lecture 7 Outline of Last Lecture I Learning Objectives II Prokaryote vs Eukaryote III Archaea IV Bacteria V Phylogenetic Tree of Life Outline of Current Lecture I Learning Objectives II In The News III Bacterial Growth IV Bacterial Habitats V Antibiotics Current Lecture I II Learning Objectives What is meant by the term Exponential Growth How can you relate this to what happened in the E coli long term evolution experiment What role s do bacteria play in human biology What constitutes the microbiome How might the use of antibiotics and antimicrobial products be changing the microbial environment In The News Why do some U S senators propose funding for NOAA buoys that are deployed as part of the GOA ON Ocean acidification reduces the formation of shells for organisms and destroys the marine diversity in coral reefs As CO2 dissolves in water it forms carbonic acid and lowers the pH of the oceans As the water gets more acidic it competes for carbonate ions and many marine These 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 III IV organisms cannot secrete the calcium carbonate shells or skeletons they need to survive Organisms can still secrete calcium carbonate but it takes more energy to do so Predicted future CO2 levels have been found to alter sensory responses and behavior of marine fishes Changes include increased boldness and activity loss of behavioral lateralization altered auditory preferences and impaired olfactory function Even with the largest estimate of CO2 from volcanoes it pales compared to the amount produced through human activity Bacterial Growth Under ideal growth conditions bacteria can double their population size in a matter of minutes as opposed to hours or even days for most unicellular eukaryotes Exponential Growth increases proportional to current value Bacteria are asexual and can double in numbers quickly through binary fission a Lag Phase Upon initial inoculation there will not be any cell division b Log Growth Phase If resources are unlimited maximum cell division will occur c Stationary Phase When resources become scarce cell division will cease d Log Death Phase Once resources are fully depleted the population crashes Bacterial Habitats a Hydrothermal vents Giant tube worms near hydrothermal vents rely on chemosynthetic bacteria in their body cavity to produce food for the animal host b Human Body The human body is composed of approximately ten trillion cells The number of bacteria in and on the human body is at least ten times as many hundred trillion cells Different parts of the body have different distributions of bacteria A newborn s close physical contact with their mother is the primary source for microbial flora both on the skin and in the intestinal tract V Acne is associated with two of the strains but individuals with the third strain of P acnes appear to be free of acne The bacterium prevents other species from becoming established on the skin About 60 by dry weight of human feces is made up by gut bacteria Antibiotics Antibiotics can wipe out the natural flora that inhabits the human intestinal tract This is like clear cutting a forest in which all sorts of weeds can colonize the barren biological landscape Many young people become infected with Clostridium difficile after they have received antibiotic treatment for acne Antimicrobial soaps and shampoos may be selecting for resistant strains of bacteria which can transfer genes to pathogens Probiotics are good bacteria yougurt