2 CLE Describe the events which occur during the major biogeochemical cycles. You will know you have mastered this standard when: You can predict how changes in a biogeochemical cycle can affect an ecosystem
3 Objectives:Analyze the flow of nutrients in each biogeochemical cycle.Evaluate the impact that humans have on the biogeochemical cycles.
5 What sustains life on Earth? Solar energyThe cycling of matter, energy & nutrientsGravity
6 Two Secrets of Survival: Energy Flow and Matter Recycle An ecosystem survives by a combination of energy flow and matter recycling.
7 MATTER CYCLING IN ECOSYSTEMS Nutrient Cycles: Global RecyclingGlobal Cycles recycle nutrients through the earth’s air, land, water, and living organisms.Nutrients - the elements and compounds that organisms need to live, grow, and reproduce.
8 Macromolecule Review What element does every organic organism contain? What are the 5 major elements that create all the macromolecules?CarbonCarbonHydrogenOxygenNitrogenPhosphorous
9 Think – Pair – ShareWhat would happen to these elements if they were only capable of being used once?Think about every time an organism is created and/or destroyedThey would begin disappearing (dwindling in supply)– like fossil fuels
10 Biogeochemical Cycles These are just illustrations or representations to show how substances move through air, water, soil, rock and living organisms.
11 Decomposition Decomposers: ultimately responsible for recycling of chemical nutrientsreleasing the nutrients in detritusThis makes nutrients available again to the autotrophs in the ecosystem
12 Recycling What nutrients get recycled? Carbon Dioxide Oxygen Water NitrogenPhosphorous
14 Movement of Water Three important processes: Evaporation – adds water as vapor to atmosphere (heat)Bodies of water, soil, animal bodies, etc.Transpiration – water evaporates from the leaves of plantsPrecipitation – water released from the atmosphere (temperature, air pressure)Rain, snow, sleet, hail or fog
16 Think-pair-share What human activities effect the water cycle? What do we do as humans that could have positive or negative effects on this cycle2 minutes
17 Effects of Human Activities on Water Cycle We alter the water cycle by:Withdrawing large amounts of freshwater.Clearing vegetation and eroding soils.Polluting surface and underground water.Contributing to climate change.How do these changes affect the surrounding ecosystems?
18 Objectives:Analyze the flow of nutrients in each biogeochemical cycle.Evaluate the impact that humans have on the biogeochemical cycles.
30 Nitrogen Uses: Proteins Nucleic Acids Enzymes, skin, muscles, etc. DNA RNA
31 Forms of NitrogenNitrogen is found in many forms in the atmosphere / ecosystemN2 = nitrogen gas (79% of atmosphere)N2O = nitrous oxideNH3 = ammoniaNH4 = ammoniumNO3 = nitrateNO2 = nitrite
32 Nitrogen FixationConverting N2 gas to nitrate (only usable form of nitrogen for most plants)2 types:Natural = lightning, fires and bacteriaHuman = fossil fuel combustion, fertilizer manufacturing
33 Nitrogen-fixing bacteria bacteria that transform Nitrogen gas into a usable form (Nitrate)Live in the soilMay live in the swellings on the roots of some plants (ex. Beans, peas, clover)These plants provide sugars for the bacteria, and the bacteria provide usable nitrogen.
34 Recycling Nitrogen Where is Nitrogen found? Dead organisms (as proteins & nucleic acids)Urine & dungDecomposers: break down and release Nitrogen as NH3 (ammonia)
35 Nitrogen ProcessesAmmonification – converting NH3 (ammonia) to NH4 (ammonium)Nitrification – converting NH4 (ammonium) into NO2 (nitrite) or NO3 (nitrates)Denitrification – anaerobic bacteria break down NO3 (nitrates) and release N2 (nitrogen gas) into the atmosphere
36 Nitrogen Sources: Plants = Nitrates from the soil Use to form proteinsAnimals = eating plants/organisms and digesting the proteins and nucleic acidsHumans = have doubled the amount of fixed N2 in the atmosphere in the last 100 years.HOW?
37 Too much of a good thing?Too much nitrogen in aquatic ecosystems results in:Eutrophication = excess nutrients stimulate plant growth (algal blooms); when these plants die, decomposers use up the available oxygen during decomposition.
40 Think-pair-share What human activities effect the Nitrogen cycle? What do we do as humans that could have positive or negative effects on this cycle2 minutes
41 Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by:Adding gases that contribute to acid rain.Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone.Contaminating ground water from nitrate ions in inorganic fertilizers.Releasing nitrogen into the troposphere through deforestation.
42 Effects of Human Activities on the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.
43 How does this affect the surrounding ecosystems? Acid raincreation of ground level ozonegroundwater contaminationeutrophication.
47 OverviewMovement of phosphorus from the environment, to organisms, and back to the environmentSlow processNormally does not occur in atmosphere because phosphorus rarely occurs as a gas
48 Where do organisms get phosphorus? Phosphorus Uses:Essential material for animalsForm bones, teeth, molecules (DNA/RNA)Where do organisms get phosphorus?Plants = absorb from soil and waterAnimals = eating plants & other organisms
49 CycleRocks erode, and small amounts of phosphorus dissolve as phosphate PO4 3-, in soil and waterExcreted in wastes from organismsReleased by decomposers from dead organismsPlants absorb from soil and water, through rootsAnimals eat plants/other organismsSome in fertilizers and applied to fields/cropsWashes off into streams, groundwater and soil
51 Think-pair-share What human activities effect the Phosphorus cycle? What do we do as humans that could have positive or negative effects on this cycle3 minutes
52 Effects of Human Activities on the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer.We reduce phosphorous in tropical soils by clearing forests.We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.
54 Environment vs Habitat Many species can survive in more than one environment.But each species has its “home” or habitat.Fish may be able to live in fish tanks, but would rather live in the wild
55 What do organisms need to survive? Basic requirements for survival include:FoodWaterShelter
56 CompetitionAn important aspect of the struggle for survival involves competition for limited resourcesFoodWaterShelterSunlight
57 Limiting FactorsLimiting factors are factors that affect the population size of a species in a specific environment.They can be abiotic or biotic.
58 Predator – Prey relationship Predators are a biotic limiting factor.They control population size by feeding on prey.There is a delicate balance that needs to be maintained.
59 Carrying CapacityWhen all the limiting factors are considered together we can determine the maximum number of organisms that can survive in an area.
60 How do we determine the Carrying Capacity of a Species? All limiting factors must be taken into consideration.It is very difficult to determine the actual carrying capacity.
61 The Lesson of the Kaibab Deer Purpose:to graph data on the Kaibab deer population of Arizona from 1905~1939to analyze the methods responsible for the changes in the deer populationto propose a management plan for the Kaibab deer population
64 Key Idea THINK-PAIR-SHARE All organisms have the ability to produce populations of unlimited sizeBut their environment keeps their numbers in check.THINK-PAIR-SHAREHow?List examples of limiting factors.3 minutes