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I. Cycles of Matter a. Energy is crucial to an ecosystem, __________________________________________ ______________________________________________________________________ i. Water ii. Minerals iii. Life-sustaining compounds b. For most organisms, _____________________________________________________ ______________________________________________________________________ c. These common elements cannot be used by organisms unless the elements are in a chemical form that cells can take up II. Recycling in the Biosphere a. Unlike the one-way flow of energy through an ecosystem, _______________________ _____________________________________________________________________ i. Elements, chemical compounds, and matter are passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles (or Nutrient Cycles) b. Nutrient cycles pass the same molecules around again and again within the biosphere c. Energy and matter move through the biosphere very differently. d. ________________________________________ the biosphere because the body does not use up matter it changes its form. (Remember…Energy is used & only flows ONE DIRECTION!!!) e. Matter is included in an organism’s living body tissue OR it is leaves the body as waste. III. So…Why are the Cycles SOOO Important? a. Nutrients are the body’s building blocks!!! i. Organisms needs nutrients to grow and carry out life functions ii. Because nutrients are in short supply in many ecosystems, recycling of nutrients is essential for these ecosystems to keep functioning b. Nutrient cycling also keeps many chemicals from reaching concentrations that would be toxic to organisms. Importance of the Water Cycle The biological environment lives along side of the physical environment. Terrestrial organisms generally lose tremendous amounts of water, as it evaporates from their bodies. All organisms lose some water as they remove waste from their bodies. Precipitation Over Land As water condenses on condensation nuclei, it forms into rain or snow, thus the water begins to fall to the ground as precipitation. Precipitation Over Ocean Most of the water that falls as precipitation falls over the oceans. Transpiration Plants also add water to the atmosphere through the process of transpiration. o Water is lost through the leaves as a by-product of photosynthesis. Seepage from Ground As the water strikes the ground, some of it goes into the soil, gathering within water tables under the earth (adding to groundwater resources). This is called Seepage. o Water “percolates” through the soil until it reaches the water table. o Water is purified by percolating through the soil as the soil acts as a natural filter. Runoff from Surface The majority of the water that strikes the land runs across the ground, slowly collecting in streams which eventually form rivers. This is called Runoff. Evaporation from the Ocean The sun radiates the Earth's surface with heat, evaporating the water, slowly turning liquid water to water vapor (gaseous water). Most of the atmospheric water vapor comes from the oceans. o Water also evaporates from lakes, ponds, rivers, streams, puddles, drainage ditches, etc. Importance of the Carbon Cycle The biological environment depends upon plants to pull carbon into sugars, proteins, and fats. Most of the carbon returns to the physical environment through the respiration of CO2 Atmosphere Earth's atmosphere contains 0.035% carbon dioxide, CO2 Photosynthesis Using photosynthesis, plants use sunlight to bind carbon to glucose, releasing oxygen (O2)in the process. Forest Trees take in carbon in the form of carbon dioxide and fix it to organic molecules that can be used by the plant for metabolic purposes. Respiration in Plants Through metabolic processes, plants may convert glucose to other sugars, proteins, or fats. o During cellular respiration, glucose is used to produce ATP. o BOTH PLANTS AND ANIMALS RESPIRE (breathe), so they release CO2 during cellular respiration! o Plants consume more CO2 through photosynthesis than they can produce as a byproduct. o Plants also use O2 for cellular respiration, but they use less than they produce as a byproduct. Plant Consumption Animals obtain their carbon by eating and digesting plants, so carbon moves through the biotic environment through the trophic system. Animal Consumption Herbivore eat plants, but are themselves eaten by omnivores or carnivores. Respiration in Animals Animals take in oxygen and give off carbon dioxide as a waste product of cellular respiration. Decay When organisms die, decomposers consume their bodies. o In the process, some of the carbon returns to the physical environment by way of fossilization. o Some of it remains in the biological environment as other organisms eat the decomposers. Detritus Feeders The fancy word for decomposers and scavengers … those organisms that feed upon decaying plant and animal remains and waste products. Respiration in Detritus Feeders Like the other plants and animals mentioned, they too release CO2 into the atmosphere. Conversion to Fossil Fuels Decayed plant matter that contained large quantities of organic carbon molecules were exposed to high pressure and heat over time which created fossil fuels like oil, coal, and natural gas. Fossil Fuel Processing/ Uses of Fossil Fuels Fossil fuels are extracted from the earth and refined into usable sources of energy o Fossil fuels are non-renewable meaning that they will eventually run out o Fossil fuels are used in coal-fired power plants to produce electricity o Oil is refined into a wide variety of products including gasoline o Natural gas is commonly used in the home for heating, cooking, and clothes dryers. Products of Combustion When fossil fuels are burned, they release the stored carbon back into the atmosphere o Increases of CO2 in the atmosphere contributes to the greenhouse effect because carbon molecules efficiently trap heat o Sulfur is also released which mixes with oxygen and water in the air to form sulfuric acid, a major contributor to acid rain. Forest Fires Forests contain large quantities of carbon locked up in the plant matter. When forest catch on fire, large quantities of carbon can be released into the atmosphere Exchange of Oceans CO2 in the atmosphere can dissolve into ocean water. There it mixes with calcium to help form calcium carbonate which is used by organisms to form shells, bones, and coral structures. o Likewise, when ocean water warms up, less CO2 can be held in the water so it is released into the atmosphere. o Marine sediments eventually break down dissolving the carbon back into the water. Importance of the Nitrogen Cycle All organisms require nitrogen to make amino acids which are used to make proteins. Many different forms of nitrogen in the biosphere Organic nitrogen is continually recycled by plants and animals. Atmosphere Nitrogen-containing compounds act as nutrients in streams and rivers as well as in the soil. o Nitrogen gas makes up 78-79% of Earth's nitrogen gas (N2). atmosphere, but most organisms can not use o Nitrogen gas is not usable by plants or animals directly. Nitrogen Fixation During electrical storms, nitrogen gas can be converted into NO3- (nitrate) during a process called atmospheric nitrogen fixation Legume Plants & Nitrogen Fixation Certain types of bacteria that live freely in the soil or within root nodules of legumes can convert the nitrogen gas into ammonia during the process called bacterial nitrogen fixation. Nitrogen Fixing Bacteria Found in soil AND on legume roots, they change the N2 (gas) to ammonia. Ammonification The conversion of nitrogen gas to ammonia (hence ammonification) is key to the fixation process. o Some plants can use ammonia directly but most need nitrogen changed to nitrates through the next process. Nitrification Other types of bacteria that live in the soil change ammonia to nitrates. Nitrosomonas These bacteria start the nitrification process by converting ammonia to nitrites. Nitrobacter These bacteria finish the job by converting the nitrites to nitrates Consumption by Plants Nitrates are taken up by autotrophs Consumption by Animals Animals consume the autotrophs and therefore obtain their nitrogen needs. Denitrification Some soil bacteria take nitrates and convert it into N2, returning nitrogen gas back into the atmosphere. o The breaking apart of the nitrates is where this term comes from. Importance of the Phosphorous Cycle All organisms require phosphorus because it forms part of life-sustaining molecules like DNA/RNA; Not very common in the biosphere Erosion by Rock Sedimentary rocks act like a “sink”, conserving much of the phosphorus for future eons. o When rock erodes away, the phosphorus is released into water where it is carried away and deposited as phosphate (combined with oxygen). Absorption by Plants Plants absorb phosphorus from water and soil into their tissues, tying them to organic molecules. Concentration in the Plant Tissue Dissolved phosphates are readily absorbed by plants and accumulate in their tissues. o These phosphates are then used in the production of vital organic molecules (like DNA and RNA). Plant Consumption & Grazing Once taken up by plants, phosphorus is available for animals when they consume the plants. Plant Waste When plants die, bacteria decompose their bodies, releasing some of the phosphorus back into the soil. Animal Waste Animal wastes along with the remains of dead animals is also released back into the soil. Runoff to the Oceans Since phosphate can be dissolved in water and carried away, it will eventually reach the oceans. o There the phosphates are incorporated into the tissues of fish and other marine organisms. Marine Sediment Scales, bones, etc. o Can be returned to the land when a marine organism is consumed and that consumers waste (or dead body) is deposited on the land again. Geologic Upthrust Over time, ocean sediments that are made up of dead organisms that contain the phosphates become exposed through plate movement and upthrusts. o Erosion of these sedimentary rocks begins the process again.