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ENVS 202 1st Edition Lecture 9Outline of Last Lecture I. ReviewII. BiodiversityIII. Bullfrogs and Invasive SpeciesOutline of Current Lecture I. Lyme Disease EcologyII. NitrogenCurrent LectureI. Lyme Disease EcologyForests in suburban areas increase the contact between bacteria, ticks, and humansMice are a natural reservoir for Lyme disease, ticks biting mice get infectedAs species richness increases, Lyme frequency decreasesEmergence of Lyme is a direct result of biodiversity lossWho are some of the “players”?Spirochete bacterium (Borreliaburgdorferi), causative agent of Lyme disease ticks, which harbor and transmit the bacteriumHosts to the ticks: mice, deer, raccoons, humans, squirrels, shrewsOther variables of Lyme diseaseNumber of ticks and tick hosts presentPercent of ticks infectedHabitat destruction/fragmentation on vertebrate speciesThese 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.How do ticks affect the abundance of the bacterium?More ticks, more bacteriumWhat effects do ticks have on mice?More ticks, fewer miceWhat effects do mice have on ticks?More mice, more ticksMice feed ~800 tick larvae per acreThe percentage of tick larvae on mice that become infected is very high compared to any other hostThe smaller the forest area, the larger the density of infected ticks“Dillution effect”: larger area, larger species richness, less infected nymphsWhat other effects does loss of diversity have?Reduction in resiliencySusceptibility to invasive speciesLoss of key trophic interactionsII. NitrogenWhat is photosynthesis?CO2 + H2O + sunlight = (CH2O)n = O2Carbon dioxide and water, using energy from light, produce carbohydrate and release oxygenNutrient: Used For: Obtained From:C (carbon), O (oxygen), H (hydrogen)Basic skeleton of organic moleculesThe atmosphereN (nitrogen), P (phosphorus),S (sulfur)Constituents of proteins, nucleic acidsOrganic matter in soilCa (calcium), K (potassium), Mg (magnesium)Osmotic regulation, membranesSoil solutionFe (iron), Mn (manganese), Mo (molybdenum)Enzyme cofactors Soil solutionC, H, and O are needed in great quantities, but rarely limit plant growthN, P, and S are needed in moderate quantities, and often do limit plant growthFe, Mo, B, Zn, and other micronutrients are essential, but needed in such small quantities that they rarely limit growthExcept carbon and oxygen, all nutrients come from soil via plant rootsNitrogen makes up 80% of the atmosphereOnly bacteria and archaea can utilize atmospheric NHow do animals deal with excess nitrogen?Plants make their own amino acids and only take up the nitrogen that they needConversion from one form to another happens throughNitrogen fixation: diatomic N converts to ammoniaNitrification: ammonia converts to nitrides/nitratesDe-nitrification: nitrates convert to gaseous NHow do natural and anthropogenic sources of nitrogen compare?Humans are responsible for about half of all nitrogen added to ecosystemsNatural: biological fixation, lightningAnthropogenic: nitric fertilizer, nitrogen-fixing crops, fossil fuelsInternal cycling of N is huge, N is limiting in most terrestrial systems, more is recycled than leaves the systemsIf it isn’t recycled, there is the process of eutrophication: an influx of nutrients support algae, consumes dissolved oxygen in


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