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86 Cards in this Set
- Front
- Back
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What are the levels of ecology? |
population, community, and ecosystem |
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What is a biogeochemical cycle? What are the four primary cycles? |
- describes how essential biological molecules transition between forms - water, nitrogen, phosphorus, and carbon |
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What are cycles divided into? |
pools (reservoirs) and fluxes (pathways) |
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What is the problem with water accessibility? |
most water is not available to other organisms; 98.5% of freshwater is in the form of ice or groundwater (less than .02% of all water on Earth is directly available) |
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How do humans affect the global water cycle? |
storage of water in reservoirs, groundwater mining, irrigation, urbanization, deforestation, wetlands |
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What are the six horizons of the soil structure |
O, A, E, B, C, R |
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O HORIZON |
consists of recently fallen and decaying plant material; heavily affected by temperature and weather rich in organic matter and supports a high biomass of soil organisms, especially decomposers |
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A HORIZON |
topsoil, made of mostly inorganic material; often has a dark brown color consists mainly of inorganic material and is generally rich in nutrients but includes significant amounts of organic matter |
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E HORIZON |
forms as clay particles and dissolved material are transported down the soil profile to the B Horizon |
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B HORIZON |
a depositional soil layer in which materials transported from the A and E Horizons accumulate |
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C HORIZON |
consists mainly of moderately weathered parent material |
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R HORIZON |
partially weathered, consolidated (broken down) bedrock |
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What is deposition? What is sedimentation? What is weathering? What is erosion? What is leaching? |
D: adding material S: soil that is moved and deposited by water W: breaking down parent (original) material E: movement of material L: loss of water soluble nutrients |
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What is the change in soil horizons over time? |
1. A, C, R 2. O, A, B, C, R 3. O, A, E, B, C, R |
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What is gross primary production? What is net primary production? |
GPP: the amount of carbon fixed by plants through the process of photosynthesis NPP: gross primary production minus the amount that is used by respiration |
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What is the key takeaway from nutrient cycling? |
although plants can make their own sugars with the help of sunlight, CO2, and water, several nutrients (nitrogen and phosphorus in particular) are critical for plant performance |
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How much of Earth’s atmosphere is nitrogen? Describe N2. |
- about 74% - it has a triple bond between its two atoms and is very stable in the atmosphere |
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Why do plants need nitrogen? |
- rubisco is critical in converting CO2 into sugars and is likely the most common enzyme on Earth (it is made up of lots of nitrogen) |
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What is nitrogen fixation? |
taking N2 from the atmosphere and reducing it to NH3 (ammonia), which can be used by organisms |
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What is ammonification? |
converting nitrogen in organisms (or waste) into NH4+ (ammonium) during decomposition |
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What is nitrification? |
converting ammonium to nitrites (NO2-) which in turn can be converted into nitrates (NO3-), which can be used by fungi and plants |
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What is denitrification? |
the release of nitrogen (N2) into the atmosphere by anaerobic bacteria |
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How does nitrifying bacteria perform biological filtration? |
by oxidizing ammonium to nitrite and nitrite to nitrate |
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Where is nitrogen found in each of these terrestrial environments? tundra, taiga, grassland, deciduous forest, savanna, equatorial forest |
Tu: predominantly soil Ta: 50% soil, the rest majority above ground G: 75% above ground/roots, the rest soil DF: pretty evenly split among the three S: majority above ground, the rest mostly roots EF: 75% above ground, the rest a mix of soil and roots |
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What is phosphorus? Where is it cycled? Where is it released from? |
- an important biological molecule that is relatively rare in the atmosphere - mostly between land, water, and living organisms - sedimentary rock |
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What is phosphorus essential for? Where is it found? What is not an important stage in phosphorus cycling? |
- energetics, genetics, and the structure of living things - ATP, DNA, and phospholipid molecules - the air (phosphorus is not found in an gaseous state) |
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What is the major source of new phosphorus to ecosystems? How is organic phosphate useful to plants? What is the available form to plants? What form is phosphorus not found in? |
- the weathering of primary minerals - only if it converted to phosphate (mineralization) first - phosphate (PO4 3-) - a gaseous state |
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When did farming begin? What has selective breeding done? What have many crops done to the soil? |
- at the end of the last ice age, 10,000 years ago - dramatically altered the nature of crops and animals - they quickly depleted the nutrients in the soil |
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What did Norman Borlaug do (and what was it called)? What did he win? Who did his work save? |
- he led selective breeding efforts in Mexico, India, and Pakistan that dramatically increased crop yield (called the Green Revolution) - he won the Nobel Peace Prize (among many other honors in the United States and India) - it saved over 1 billion lives from starvation |
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What are the natural sources of nitrogen fixation? What are the human sources? |
- the vast majority come from biological fixation with a small percentage coming from lightning - over half come from nitrogen fertilizer with a small chunk coming from nitrogen-fixing crops and an even smaller percentage coming from fossil fuels |
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What has erosion done in Iowa over the past 150 years? What is the average soil loss in North America and Europe per year? |
- it has removed over 50% of the topsoil in Iowa - about 17 million tons (or 37,500 pounds of soil per hectare (100 m²)) per year |
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What is conventional tillage agriculture? What is it effective for? What is the problem with it? |
- breaking up soil clumps using a tiller (in modern agriculture, this is done with a tractor) - it is effective for controlling weeds and planting crops - it leaves exposed soil that is very susceptible to erosion by wind and water |
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What is overgrazing? How much soil do overgrazed plots lose per year? What can this create? |
- livestock reduce plant cover and compress soil, making it harder for roots to grow and disturbing the topsoil - over 100 tons of soil per hectare per year - washed out gullies and an increased rate of desertification in the Sahara |
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What is clearcutting? How and where is it normally done? What was clearcutting associated with in British Columbia? |
- the practice of removing all of the trees from a large area - it is normally done using large equipment and on steep terrain - clearcutting 10% of a basin was associated with a 50% increase in the amount of soil erosion (measured by the mass of sediment in the streams) |
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How is much of the nitrogen and phosphorus in the soil lost? What does this loss require? The nitrogen and phosphorus in the Mississippi River drainage has led into the Gulf of Mexico, where it has created what? |
- roughly 2 metric tons is lost by erosion - replacement by fertilizers - a “dead zone” of hypoxic water that lacks enough oxygen for most animals to breathe in |
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How and for how long has slash and burn farming and grazing occurred? What do the nutrients from burned trees fertilize? What is the problem with the fertilizer that comes from the nutrients? |
- it has occurred at small scales in the tropics for centuries - they fertilize the soil for crops - it leaches out of the soil within a few years, prohibiting farming and inhibiting the regrowth of the forest |
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What is the difference between polyculture and monoculture? Which one is better for the crops? |
- polyculture is more labor intensive, it slows the spread of pathogens, and it retains nutrients in the soil, whereas monoculture is easier and more efficient, it facilitates the spread of pathogens, and it requires fertilization - ultimately, polyculture leads to lower rates of infection in plants and is overall better for growing crops |
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How is much of the nitrogen and phosphorus in the soil lost? What does this loss require? The nitrogen and phosphorus in the Mississippi River drainage has led into the Gulf of Mexico, where it has created what? |
- roughly 2 metric tons is lost by erosion - replacement by fertilizers - a “dead zone” of hypoxic water that lacks enough oxygen for most animals to breathe in |
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How and for how long has slash and burn farming and grazing occurred? What do the nutrients from burned trees fertilize? What is the problem with the fertilizer that comes from the nutrients? |
- it has occurred at small scales in the tropics for centuries - they fertilize the soil for crops - it leaches out of the soil within a few years, prohibiting farming and inhibiting the regrowth of the forest |
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What is the difference between polyculture and monoculture? Which one is better for the crops? |
- polyculture is more labor intensive, it slows the spread of pathogens, and it retains nutrients in the soil, whereas monoculture is easier and more efficient, it facilitates the spread of pathogens, and it requires fertilization - ultimately, polyculture leads to lower rates of infection in plants and is overall better for growing crops |
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What are some strategies for reducing soil loss? |
plowing along a contour rather than over it, terracing, and tree windbreaks |
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How is much of the nitrogen and phosphorus in the soil lost? What does this loss require? The nitrogen and phosphorus in the Mississippi River drainage has led into the Gulf of Mexico, where it has created what? |
- roughly 2 metric tons is lost by erosion - replacement by fertilizers - a “dead zone” of hypoxic water that lacks enough oxygen for most animals to breathe in |
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How and for how long has slash and burn farming and grazing occurred? What do the nutrients from burned trees fertilize? What is the problem with the fertilizer that comes from the nutrients? |
- it has occurred at small scales in the tropics for centuries - they fertilize the soil for crops - it leaches out of the soil within a few years, prohibiting farming and inhibiting the regrowth of the forest |
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What is the difference between polyculture and monoculture? Which one is better for the crops? |
- polyculture is more labor intensive, it slows the spread of pathogens, and it retains nutrients in the soil, whereas monoculture is easier and more efficient, it facilitates the spread of pathogens, and it requires fertilization - ultimately, polyculture leads to lower rates of infection in plants and is overall better for growing crops |
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What are some strategies for reducing soil loss? |
plowing along a contour rather than over it, terracing, and tree windbreaks |
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What is no-tillage agriculture? What is the erosion rate compared to conventional tillage? |
- farmers can drill through old plants rather than tilling them - the erosion rate is 1/20th that of conventional tillage |
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How is much of the nitrogen and phosphorus in the soil lost? What does this loss require? The nitrogen and phosphorus in the Mississippi River drainage has led into the Gulf of Mexico, where it has created what? |
- roughly 2 metric tons is lost by erosion - replacement by fertilizers - a “dead zone” of hypoxic water that lacks enough oxygen for most animals to breathe in |
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How and for how long has slash and burn farming and grazing occurred? What do the nutrients from burned trees fertilize? What is the problem with the fertilizer that comes from the nutrients? |
- it has occurred at small scales in the tropics for centuries - they fertilize the soil for crops - it leaches out of the soil within a few years, prohibiting farming and inhibiting the regrowth of the forest |
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What is the difference between polyculture and monoculture? Which one is better for the crops? |
- polyculture is more labor intensive, it slows the spread of pathogens, and it retains nutrients in the soil, whereas monoculture is easier and more efficient, it facilitates the spread of pathogens, and it requires fertilization - ultimately, polyculture leads to lower rates of infection in plants and is overall better for growing crops |
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What are some strategies for reducing soil loss? |
plowing along a contour rather than over it, terracing, and tree windbreaks |
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What is no-tillage agriculture? What is the erosion rate compared to conventional tillage? |
- farmers can drill through old plants rather than tilling them - the erosion rate is 1/20th that of conventional tillage |
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What makes a product organic? What are some examples of organic products? What do organic products not contain? How are the organic crops grown? How do modern organic farming yields compare to those of conventional farming? What is the downside to organic farming? |
- “organic production is a production system that responds to site-specific conditions by integrating cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biological diversity” - organic fertilizers, such as manure and compost, and organic pesticides (which can still be very toxic) - GMOs - through crop rotation - they are very similar in size - it can be expensive and time consuming |
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What is biochar made from? How does it help the soil and plants (6)? |
- recycled materials, such as pines killed by bark beetles or trees damaged by fire - it helps hold soil moisture and release it in drought / it increases soil microbial activity / it holds and releases soil nutrients / it reduces the leaching of nutrients and fertilizer / it increases plant growth and rooting / there is less plant disease (the benefits of one application are long lasting) |
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What is integrated pest management? What techniques does it use (4)? |
- uses a variety of techniques to minimize the harmful impacts of pesticides - planting pest-resistant crop varieties / rotating crops / targeted traps rather than spraying / GMOs such as BT modified organisms and herbicide-resistant crops |
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What is integrated pest management? What techniques does it use (4)? |
- uses a variety of techniques to minimize the harmful impacts of pesticides - planting pest-resistant crop varieties / rotating crops / targeted traps rather than spraying / GMOs such as BT modified organisms and herbicide-resistant crops |
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What is the benefit of local farming? |
besides aiding local farmers, it it roughly 5x cheaper than buying in the U.S. and 2.5x cheaper than buying in Africa |
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What is a wetland? Where can wetlands develop? What is so good about wetlands? |
- a habitat that is inundated by water at least some of the time and that supports plants adapted to water-saturated soil - in shallow basins, along flooded riverbanks, or on the coasts of large lakes and seas - they are among the most productive biomes on Earth and are home to diverse invertebrates and birds |
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What is the most prominent physical characteristic of streams and rivers? Why is it so important? |
- the current - it moves sediment, nutrients, and pollutants |
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What is integrated pest management? What techniques does it use (4)? |
- uses a variety of techniques to minimize the harmful impacts of pesticides - planting pest-resistant crop varieties / rotating crops / targeted traps rather than spraying / GMOs such as BT modified organisms and herbicide-resistant crops |
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What is the benefit of local farming? |
besides aiding local farmers, it it roughly 5x cheaper than buying in the U.S. and 2.5x cheaper than buying in Africa |
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What is a wetland? Where can wetlands develop? What is so good about wetlands? |
- a habitat that is inundated by water at least some of the time and that supports plants adapted to water-saturated soil - in shallow basins, along flooded riverbanks, or on the coasts of large lakes and seas - they are among the most productive biomes on Earth and are home to diverse invertebrates and birds |
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What is the most prominent physical characteristic of streams and rivers? Why is it so important? |
- the current - it moves sediment, nutrients, and pollutants |
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What do plants produce in habitats with low nitrogen? What happens when these chemicals leach into the water? |
- chemicals called tannins (to reduce herbivory) - they lower its pH (making it acidic) and turn it into tea |
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The Amazon River is the world’s ______ and _______ river. The _____ and _______ Rivers rank as the 5th and 6th in the world. |
- longest and largest - Negro and Madeira |
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What is integrated pest management? What techniques does it use (4)? |
- uses a variety of techniques to minimize the harmful impacts of pesticides - planting pest-resistant crop varieties / rotating crops / targeted traps rather than spraying / GMOs such as BT modified organisms and herbicide-resistant crops |
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What is the benefit of local farming? |
besides aiding local farmers, it it roughly 5x cheaper than buying in the U.S. and 2.5x cheaper than buying in Africa |
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What is a wetland? Where can wetlands develop? What is so good about wetlands? |
- a habitat that is inundated by water at least some of the time and that supports plants adapted to water-saturated soil - in shallow basins, along flooded riverbanks, or on the coasts of large lakes and seas - they are among the most productive biomes on Earth and are home to diverse invertebrates and birds |
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What is the most prominent physical characteristic of streams and rivers? Why is it so important? |
- the current - it moves sediment, nutrients, and pollutants |
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What do plants produce in habitats with low nitrogen? What happens when these chemicals leach into the water? |
- chemicals called tannins (to reduce herbivory) - they lower its pH (making it acidic) and turn it into tea |
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The Amazon River is the world’s ______ and _______ river. The _____ and _______ Rivers rank as the 5th and 6th in the world. |
- longest and largest - Negro and Madeira |
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What is an estuary? How does the salinity in estuaries vary? What is so good about estuaries? What attracts marine invertebrates and fish? Why is diversity in estuaries low (especially for plants)? What is very high in estuaries? |
- a transition area between the river and the sea - with the rise and fall of the tides - they are nutrient rich and highly productive - an abundant supply of food - the daily changes in salt concentrations is difficult for many species to handle (despite this, many species of marine life have their babies here) - net primary production |
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What are many aquatic biomes stratified into? What are the names of the layers/zones? What is the difference between the upper and middle layer? What does the bottom layer consist of? |
- zones or layers defined by light penetration, temperature, and depth - (upper) euphotic zone, (middle) aphotic zone, (lower) benthic zone - the upper zone has sufficient light for photosynthesis while the middle zone receives little light - the organic and inorganic sediment and the communities of organisms within (called the benthos) |
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What is the most extensive part of the ocean? What does much of the food for this part of the ocean come in the form of? |
- the abyssal zone (with a depth of 2,000 to 6,000 meters) - detritus (dead organic matter that falls from the productive surface water and is an important source of food) |
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What is the most extensive part of the ocean? What does much of the food for this part of the ocean come in the form of? |
- the abyssal zone (with a depth of 2,000 to 6,000 meters) - detritus (dead organic matter that falls from the productive surface water and is an important source of food) |
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What is the thermocline and what does it do? What is turnover? What does turnover mix? |
- in oceans and most lakes, the thermocline is a temperature boundary that separates the warm upper layer from the cold deeper layer - a semiannual mixing of the waters that many lakes undergo - oxygenated water from the surface with nutrient-rich water from the bottom |
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What does oligotrophic mean? What does eutrophic mean? |
- nutrient-poor and generally oxygen-rich - nutrient-rich and often depleted of oxygen |
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What does allochthonous mean? What does autochthonous mean? |
ALLO: the resources come from other places AUTO: the resources come from the same place |
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What is a fishery? When does fishery collapse occur? Is the United States a net exporter or net importer of seafood? |
- a population of a fish or shellfish in a geographic area as well as the associated economic system involved with harvesting the population - when a species falls below 10% of its historical levels - it has switched from a net exporter to a net importer |
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What is subsistence fishing? What is commercial fishing? What is aquaculture? |
- the practice of catching enough fish for one’s family plus a small amount more for bartering - catching fish for profit (the majority of fishing in the world) - the controlled growing of seafood |
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What are types of commercial/mass fishing? |
bottom trawlers, long line fishing, gillnetting, and turtle excluder devices |
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What is stock? Where on the logistic curve does the population grow the fastest? |
- the size of the population (which could include several types of metrics including the number of fish in an area of water or a spawning stream) - in the middle (where the concavity changes) |
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What is aquaculture? What is it used for? What are the problems with aquaculture? |
- the raising of freshwater or marine species in ponds or in enclosures in the wild - boosting seafood production - fish can escape, high densities lead to increased infectious diseases, there is high nutrient runoff, habitats can clear, and top trophic level fish can bioaccumulate toxins |
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SALT MARSHES |
act as barriers to waves and storm surges; filter pollutants, including sediments, nutrients, and pesticides; provide nesting, nursery, and feeding grounds for a diversity of wildlife |
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KELP FORESTS |
net primary production is among the highest of any ecosystems on Earth, providing food and shelter for an abundance of fish, as well as shore protection |
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MANGROVE FORESTS |
protect coastlines from storm waves and tsunami, while providing nursery grounds for juvenile fish, harvestable fish and shellfish, and sources of wood products |
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RIPARIAN WETLANDS |
hotspots of biodiversity and productivity; during flooding, particularly along large rivers, many species of fish move into riparian wetlands for feeding and spawning |
