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114 Cards in this Set
- Front
- Back
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What is ecology?
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Ecology is the study of the relationships between organisms and their environment.
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What are the levels of ecological hierarchy?
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Biosphere, region, landscape, ecosystem, community, interactions, population, individuals.
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What is the ecological "currency" in a biosphere?
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atoms
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What is the ecological "currency" in a region?
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individuals (atoms)
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What is the ecological "currency" in a landscape?
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individuals (atoms)
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What is the ecological "currency" in an ecosystem?
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atoms
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What is the ecological "currency" in a community?
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individuals
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What is the ecological "currency" in an interaction?
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individuals
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What is the ecological "currency" in a population?
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individuals
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What is the ecological "currency" in an individual?
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atoms
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What is a biotic - abiotic linkage?
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Occurs when a biotic factor (something living - trees, grasses, etc.) interacts with a non-living factor. An example is that the presence of trees (biotic) decreases the rate of nutrient (abiotic) runoff from soil.
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What are examples of web structures found in ecology?
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Food webs; flow of nutrients (nitrogen, phosphorus, etc.) through soil, water, and air; the skeletal system
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How can webs be affected?
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If a specific portion of the web is removed (via predation, environmental change, etc.), the web will shift to get nutrients from another source. This can cause a large increase or decrease in the size of a population especially in chains (below the extinct animal will bloom, above it will die)
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How do humans dominate ecological systems?
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Humans have a large affect on every system whether this be a direct affect such as on our food sources or via the changes we have made to the environment.
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Explain the concept of a biome.
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A biome is a major division of the terrestrial environment.
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How is earth's climate related to the biomes.
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A biome is defined by vegetation which is defined by the climate. Thus the biome type is really determined by the temperature and precipitation.
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Tropical Rainforest
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Very high trees, most biodiversity, found near the equator where temperatures are high and there is lots of precipitation year round. Have very poor quality soils - thin, acidic, lots of rain leaches nutrients from soil. Get help finding nutrients by mycorrhizae, fungi that are associated with their roots.
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Tropical Dry Forest
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Trees go dormant in the dry season, very brown. Comes to life with the rains. Occur between 10 ° and 25 °. Temperature is mostly constant, but varies more than a tropical rainforest. Very old soil, less acidic, richer in nutrients. Highly vulnerable to erosion because of the bursts of rain. Shorter trees (height depends on amount of precip.)
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Tropical Savanna
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Tropical grassland with few trees. Occur north and south of the tropical dry forests (between 10° and 20°). Major climate cycles with wet and dry season. Temperature fluctuates more than tropical dry forest. Rain storms bring lightning which can ignite dry grasses. Will kill new trees while grasses quickly resprout. Generally drier than the tropical dry forest. Soils are usually impermeable to water which encourages the growth of grasses. Has much fewer trees than dry and rain forest. Populated by wandering animals.
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Desert
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Desert circles the earth around 30° N and S. Correspond to latitudes where dry subtropical air descends, drying the landscape. Classification is not dependent on the level of rainfall, but more on the fact that evaporation and transpiration by plants dries the soil faster than it can be replaced by rains. Can be bitterly cold. Soils are incredibly low in nutrients, sometimes called lithosoils (stone or mineral soil). May contain high levels of salts, can even have a very hard layer of soil called caliche or calcium carbonate. Animal abundance can be low while diversity is high.
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Mediterranean Woodland and Shrubland
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Occur on all continents except Antarctica. Found mostly around the Mediterranean Sea. Occurs between 30° and 40° latitude. Called chaparral in North America, matoral in Spain, fynbos in Africa, mallee in Australia. Cool and moist in fall, winter, and spring. Summers are hot and dry. Creates plants that are rich in essential oils, which cause frequent and intense fires. Soil is of low to moderate fertility. Plants are typically evergreen with small tough leaves. Have highly developed mutualistic relationships with nitrogen fixing bacteria. Fires cause plants to have tough thick bark.
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Temperate Grassland
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Wide open "seas of grass". Largest biome in North America. Fair amount of rainfall though droughts do occur and can last for several years. Precipitation is usually at a maximum in the summer. Winters are usually cold and summers hot. Soils are considered to be fertile, with black soils being the most fertile followed by brown soils. Usually basic or neutral with lots of organic matter. Dominated by herbaceous vegetation. Fire occurs often and discourages the formation of trees (found only near streams and rivers). Dense root system of grasses forms sod and also prevents trees from growing. Largely been converted to farm land.
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Temperate Forest
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Found between 30° and 55° latitude. Lies mainly between 40° and 50°. Can either be coniferous or deciduous occur, where temps are not extreme and annual precip is fairly high. Usually receive more winter precip than temperate grasslands. Winters are relatively mild but can have lots of snow. Conifers are more abundant when winters are more severe or summers are drier. Soils are usually very fertile. Usually neutral or slightly acidic. Has a very large biomass. Herb layer, shrub layer, shade tolerant understory trees, then canopy. Fungi and bacteria are important consumers.
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Boreal Forests
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Also called the taiga. World of wood and water, name comes from the Greek word for "north". Confined to the northern hemisphere. Found between 50° and 65° N. Bounded either in the south by temperate forests or temperature grasslands and in the north by Tundra. Found where winters are too long and summers too short to support temperate forest. Precipitation is moderate. Evaporation rates are low because of long winters and low temperatures. Lots of forest fires when droughts occur. Soils are of low fertility, thin, and acidic. Low temps and low pH limits decomposition of plant litter and slows the rate of soil building. Dominated by evergreen conifers. Home to many animals. Species diversity is much lower.
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Tundra
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Open landscape of mosses, lichens, and small willows. Midnight sun. Rings the top of the globe. Covers most of the land north of the Arctic Circle. Very cold and dry. Though temps are not usually as extreme as in the boreal forest. Winter temps are less severe, but the summers are shorter. Solifluction slowly moves soils down slopes because of the free thaw cycles. Many grasses, sedges, mosses and lichens are found here.
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Name all the biomes and where they are found
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Tropical rain forest (equator to 10°), tropical dry forest (10° to 25°), tropical savanna (N and S of tropical dry forests - 10° and 20°), Desert (30° N and S), Mediterranean Woodland and Shrubland (30° and 40°), Temperate Grassland (Central NA and Asia), Temperate Forests (40° and 50°), Boreal Forest (50° and 65°N), Tundra (Arctic Circle)
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How are elevation effects similar to increasing latitude?
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At middle latitudes, mountains are cooler and wetter. In tropical mounts, there is less precipitation at higher elevations. In some tropical regions, the precip rises as you reach middle elevations, but decreases at the highest.
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How does Earth's tilt create the seasons.
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As the sun travels around the earth, the tilt of the Earth moves one of the hemispheres closer (summer) or farther away from the sun (winter).
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What are the major soil horizons?
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O - organic horizon made up of loose plant litter. A - mineral soil mixed with organic matter. B - Depositional horizon materials leached from A horizon are deposited here. C - weathered plant material may include rock fragments usually lies on top of bedrock.
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What are the major reservoirs in the hydrologic cycle, list them in order of largest to smallest.
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Oceans, ice, groundwater, atmosphere
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What are the processes by which water is transferred between the reservoirs?
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evaporation from the oceans moves water into the atmosphere, condenses and then falls as rain or snow. Ice melts and flows into oceans.
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List the processes that move water from the largest volume transferred to the smallest.
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Evaporation from oceans, evaporation from land, pumping of groundwater, river flow.
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Shallow marine waters
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Kelp forests, coral, shallow need lots of light. Kelp is found in subpolar regions. Coral is found in tropical regions. Kelp are limited to temperate shores, corals are restricted to warm waters.
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Marine Shores
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All coast line. Supratidal zone, upper intertiadal zone, middle intertidal zone, lower intertidal zone, subtidal zone
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Estuaries, salt marshes, mangrove forests
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found where rivers meet oceans, transition between two environments.
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Rivers and Streams
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All landscapes, made up of riparian zone (outside the active channel - transition between the aquatic environment and the terrestrial environment), hyporheic zone (transition zone between surface water flow and groundwater), phreatic zone (area below the hyporheic zone),
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Lakes
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Littoral zone (shallowest waters), limnetic zone (open lake). Vertical divisions: epilimnion (warm surface), thermocline or metalimnim (zone through which temperature changes substantially with depth), hypolimnion (coldest waters).
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How has human activity affected CO2 levels?
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Increased dramatically since the industrial revolution.
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What are the correlations between high CO2 levels and temperature?
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The last time CO2 levels were high, an ice age was occurring.
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What are the major sources of CO2 data?
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The Vostok ice core allowed scientists to determine the CO2 concentration in the atmosphere back 160,000 years. South Pole ice core gives concentrations over the last 1000 years. Direct measurements have also been made by a station on Mauna Loa in Hawaii over about 40 years.
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What is the Suess Effect?
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As more and more carbon is burned, C14 levels have decreased.
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What are the major greenhouse gases?
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CO2, CH4, H2O, O3
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Explain the greenhouse effect.
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70% of energy that hits the earth is absorb. It is reemitted as IR radiation. This can either be sent into space or reflected back to the surface of the earth. The IR radiation that is reflected bounces off of greenhouse gases, thus as their concentration increases, more and more IR radiation is reflected back to the surface of the Earth, causing the temperature to rise.
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What is nitrogen fixation a difficult chemical process.
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Nitrogen fixation requires large amounts of energy because of the triple bond that forms it.
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Why is nitrogen fixation important for life?
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Nitrogen is found in many biochemicals such as amino acids.
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What are the nitrogen fixing organisms?
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Green-blue algae (cyanobacteria), free-living soil bacteria, bacteria associated with the roots of leguminous plants, and actinomycetes bacteria which is associated with the roots of alders and other woody plants.
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Compare the rates of natural nitrogen fixation to human nitrogen fixation.
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Nonhuman process has stayed constant while the human addition has increased exponentially. Major human causes/uses of fixation are burning of fossil fuels, industrial fixation, and crop fixation.
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Where is ozone beneficial?
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Ozone is important in the stratosphere.
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Where is ozone detrimental?
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In the troposphere.
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What are the sea surface temperatures, coastal upwelling, and storm formation trends in an El Nino year?
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During El Nino, the eastern tropical sea surface is much warmer, and pressure is much lower than average. This promotes storm formation over the Pacific ocean which causes heavy rains in much of North and South America. The western Pacific is much cooler, and pressure is higher, this produces much of a drought over the western Pacific including Australia. There is also the appearance of an additional warm current off the coast of Peru
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What are the sea surface temperatures, coastal upwelling, and storm formation trends in an La Nina year?
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Surface pressure is higher than average and surface temperature is lower n the eastern tropical ocean. Brings droughts to much of North and South America. Warm water and lower pressure over the western Pacific cause many storms in the western pacific and higher precipitation in that region.
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What are the ecological repercussions El Nino?
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Produces declines in the populations of many small fish and the birds that feed on them in years when El Nino is occuring. This is caused by the increase in temperature. This region usually has relatively cool ocean temps, but during El Nino the temp increases. The warm surface water also stops upwelling and thus prevents nutrients from being brought upward.
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What is edge effect and how does it contribute to the effects of deforestation?
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When all the area around a small part of a forest is cleared, edges that weren't ever exposed to the "outside" world are now exposed. These changes in the environment effect the structure of the forest.
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What is an ecosystem?
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All the organisms that live in an area and the physical environment with which those organisms interact.
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What is the relationship between gross and net primary production?
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Gross primary production is the amount of biomass produced by all autotrophs in the ecosystem. Net primary production is the amount of biomass left over after autotrphs have met their own energetic needs. Net = gross - respiration by primary producers.
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Why is net primary production important?
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This is the true amount of energy available to the consumers in the rest of the ecosystem.
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What is a trophic level?
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A trophic level is a position in a food web and is determined by the number of transfers of energy from primary producers to that level. Plants are primary producers and are the 1st trophic level, herbivores and detritivores are are primary consumers and in the 2nd trophic level, carnivores are secondary consumers and occupy the 3rd trophic level.
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Why is energy transfer up to higher trophic levels shaped like a pyramid?
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When energy is transferred from one trophic level to a higher one, energy will be lost because of heat production, limited assimilation, and consumer respiration.
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What is the maximum ecological efficiency?
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The maximum efficiency must be less than one, the output of a trophic level can never be larger than the level below it. 0.1 is a common efficiency.
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How can a trophic cascade cause a change in the production of a primary producer?
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If a tertiary consumer population booms, the secondary consumer will dwindle, this will cause a bloom in the primary consumer which will overfeed on the primary producer.
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What is the relationship between annual net primary produciton and annual actual evapotranspiration?
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Areas with the highest primary production have the highest actual evapotranspiration. Thus rain forests have a very high AET while tundra and deserts have a very low AET.
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What are the effects of fertilizing?
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Fertilizing increases production to a greater degree in the dry meadow than in the wet meadow.
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Where at the highest rates of marine primary production found?
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The highest rates of primary production are found in areas with higher levels of nutrient availability and concentrated along the margins of continents over continental shelves and in areas of upwelling.
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What are the effects of fertilizing on marine habitats?
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Nutrient availability controls the primary production in marine ecosystems thus the addition of nutrients increases the primary production.
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How are the effects of fertilizing different between terrestrial and acquatic plants?
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Terrestrially, production is limited by temperature and precipitation for the ecosystem and by nutrient availability within the ecosystem. In acquatic systems, the availability of nutrients is all that really controls the production.
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What are the major reservoirs in the phosphorus cycle, list them from largest to smallest in size.
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Sediment below the ocean, terrestrial soil, dissolved in ocean water, mineable rock, terrestrial organisms, marine detritus, fresh water, ocean organisms, fertilizer in soil, atmosphere over land, and atmosphere over marine evironment.
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List in order of greatest to least, the concentration of phosphorus in atmospheric, geologic, and biologic pools.
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Geologic > biologic > atmospheric
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What are the major reservoirs in the nitrogen cycle?
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Oceans > soil > atmospheric
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What are the major reservoirs in the carbon cycle?
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Carbonate rock > oceans > soil > plants
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What are the chief abiotic and biotic controls on leaf decomposition?
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Abiotic - temperature, moisture, and chemical composition of litter. Biotic - composition of the leaf.
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What are the trends between climate and rates of decomposition?
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Higher moisture will cause things to decompose much quicker. Areas with higher AET will have higher rates of decomposition. Rates are also positively correlated with temperature, higher temperature = higher rate of decomposition.
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How do humans effect nutrient budgeting?
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When humans clearcut, nutrients are leached from the soil much more quickly because of the increased run off and erosion (Hubbard Brook Experiment). Humans also concentrate nutrients by removing them from other areas.
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Where is optimal growth temperature found on a graph of temperature vs. output?
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The graph will peak, thus the temperatuer where output is the highest.
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How can one infer an animals habitat from its growth curve?
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If the curve has a peak a low temperature, the species most likely lives in a cold area.
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What is adaptation, what is acclimatization, how do these compare?
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Acclimatization occurs on a short time scale with the same genotype of an organism. Can be tested by placing two organism of the same genotype in different environments, it their growth curves differ, then the plant is acclimatizing. Adaptation is the evolutionary process by which the genetics of the organism are changed to adapt to a new environment.
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What is the relationship between water vapor pressure defecit and rate of evaporation?
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Directly related, low VPD = low rate of evaporation
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What are the components of water potential?
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Wp = Wsolute(reduced by dissolved subs) + Wmatric(reduced by adhesion) + Wpressure(reduced by evaporation)
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What are the major components of plant water balance?
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Wip (internal water) = Wr(roots) + Wa(air) - Wt(transpiration) - Ws(secretion)
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What direction does water move based on potential?
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It moves from a high potential to a low potential.
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What direction is the water potential in an organism?
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Highest in the roots, lowest in the extremeties (leaves)
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Define the components of animal water balance.
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Wia(internal)= Wd(drinking) + Wf(food) + Wa (absorbed from air)- We(evaporation) - Ws(secretion)
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Define a hyperosmotic environment.
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Concentration of solutes inside the organism are higher than the exterior environment and thus water moves into the organism to reduce the concentration.
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Define a hypoosmotic environment.
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The concentration of solutes inside the organism is lower than the environment outside the organism and thus water moves out of the organism to increase the concentration of solute inside the organism (salts can also move in).
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Define an isoosmotic environment.
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Concentration is equal inside and outside, at equilibrium.
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How do marine fish combat their hypoosmotic environment?
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Drink lots of water, because water moves out. Excrete Cl, have concentrated urine.
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How do freshwater fish combat their hyperosmotic environment?
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Drink litte, dilute urine, absorb CL
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What types of plants use C3 photosynthesis, why?
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Plants that live in moist and cool environments use C3 photosynthesis. In C3, the plant must open its stomata which allows water and CO2 to escape. The stomata must stay open even longer because RuBP carboylase (the enzyme that binds CO2 to RuBP) has a low affinity for CO2.
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What types of plants use C4 photosynthesis, why?
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Plants that live in arid conditions use C4 photosynthesis. C4 separates carbon fixation and the light dependent reactions into separate cells. The CO2 is stored in a cell that readily takes up CO2 meaning the stomata stay open for a shorter period of time. They then transfer it to the RuBP carboxylase where they react.
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What types of plants use CAM photosynthesis, why?
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Limited to succulent plants in arrid and semiarid environments. Carbon fixation occurs at night, when temperatures are low and there is not sun to evaporate water. The CO2 is combined with PEP and stored until dylight when the compound in broken down and used for C3 photosynthesis.
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What is the diet of a herbivore?
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herbivores consume only plants.
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What is the diet of a carnivore?
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Carnivores only consume other animals.
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What is the diet of a detritivore?
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Live off of dead tissue, usually plant tissue.
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What problems do herbivores face by only eating plants?
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Plants contain very low levels of nitrogen and lots of carbon. They also have lots of cellulose and lignin, which animals cannot digest. These serve as a type of chemical defense. Plants also can synthesize different toxins.
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What types of plants will herbivores prefer?
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They will prefer the plants that are less protected.
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How does the weight of a carnivore compare with the weight of it's prey?
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A larger carnivore prefers to prey on larger animals. This is called size selective predation.
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Describe a Type 1 functional response and the types of animals that feed this way
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A type I function response occurs when feeding rate increases linearly as the prey density increases until it suddenly levels off. This is only found in animals that do not have to process their food such as filter feeds.
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Describe a Type 2 functional response and the types of animals that feed this way
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Feeding rate rises linearly at first and low food density and the rises more slowly at intermediate food denisty before leveling off at high food density. The decrease in rate for the intermediate food density is brought about by the amount of time that it takes for the animal to find good. This is the most common.
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Describe a Type 3 functional response and the types of animals that feed this way
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S-shaped. At low food density, increase more slowly than during either type 1 or type 2 responses. Food intake then rises steeply at intermediate food densities before leveling off at high food densities.
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Give examples of the principle of allocation in reference to the optimal theory of foraging.
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In grasses, when the concentration of nitrogen in the soil decreases, they allocate more resources to growing shoots as opposed to growing roots (roots have no purpose when there is no nitrogen in the soil).
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What is a population?
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A population is all individuals of a given species in a prescribed area
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What are the factors that affect population growth, give the equation.
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Nnow(number now) = Nthen(number then)+ B(births) – D(deaths) + I(immigrants) - E(emigrants)
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Describe the three types of survivorship curves and give examples of organisms that follow each.
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In Type I, juvenile survival rate is high and death occurs mostly in the older population (humans). Type 2 - Die at equal rates regardless of age (common mud turtles). Type III - Extremely high rate of mortality among the young followed by realtively high rate of survival (animals that lay many eggs).
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Describe how to create the lx column in a life table.
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lx is the portion surviving to age x to calculate, take total population and subtract the number of organisms that died in the previous year.
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Describe how to calculate R0.
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Sum the product of lx and mx. If R0 is > 1 the population is growing.
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What shape will a population distribution be if the population is increasing?
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Large bottom, small top.
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What shape will a population distribution be if the population is static?
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Rectangle
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What shape will a population distribution be if the population is increasing?
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Small bottom, large top
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When does geometric growth occur?
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In organisms that grow by pules reproduction such as perennial flowers.
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When does a population undergo exponential growth?
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This will only occur for short periods of time, but it does occur. It can be seen if a population has a number below what can be supported by the habitat.
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What is a density dependent factor?
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A density dependent factor is something that has an variable affect based on the size of the population. An example would be a disease.
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What is a density independent factor?
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An abiotic factor such as a flood or extreme temperature
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When is a logistic population growing the fastest?
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When the population is equal to 1/2 of the carrying capacity.
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What is a bioclimatic model?
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Models similar areas based on climate to determine where a species will spread to. If an ant from Brazil is introduced to the southern US, you can map where in the southern US has similar rainfall and temperature to the specific region of Brazil from where the ant comes to determine where it will spread.
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When are subpopulations are the most successful?
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When the are large and close together.
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