Term
| explain how the first and second laws of thermodynamics apply to ecosystems |
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Definition
| these laws apply to ecosystems in that the total amount of energy stored in organic molecules must equal the total solar energy intercepted by the plant minus the amounts reflected and dissipated as heat. Energy conversions in an ecosystem are inefficient, so some energy is always lost as heat. Because of this, energy is constantly leaving the system as heat. This means that without an constant energy source-- the sun-- most ecosystems would vanish because energy does not cycle back into the systems. It is constantly entering, flowing through, and exiting. |
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Term
| define and compare gross primary production, net primary production, and standing crop |
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Definition
Gross primary production is is the total primary production, meaning the total amount of light energy converted to chemical energy by autotrophs.
Net primary production is GPP minus the energy used by the primary producers for their respiration. It is usually about half of the GPP. Net primary production is the amount of new biomass added in a given period of time.
standing crop is the total biomass of photosynthetic autotrophs present. |
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Term
| explain why energy flows but nutrients cycle within an ecosystem |
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Definition
energy is lost during energy conversions, so a constant input is needed. ecosystems could not function if they were given a set amount of energy to consume, because eventually all of it would leave the system. therefore, energy flows through ecosystems.
nutrients are mass, and therefore they do not lose substance as they are transferred in the system, and can be reused over and over again. |
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Term
| explain what factors may limit primary production in aquatic ecosystems |
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Definition
| primary production is limited by the availability of light and limiting nutrients. |
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Term
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Definition
| the amount of light energy converted to chemical energy by an autotroph |
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Term
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Definition
the amount of chemical energy in consumers' food that is converted to their own new biomass during a given period.
how energy from food is used for growth |
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Term
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Definition
= (net secondary production*100%)/(assimilation of primary production)
the percentage of energy stored in assimilated food that is not used for respiration.
birds and mammals typically have low efficiency: 1-3% because they have to use so much energy maintaining a constant high body temp
fishes: 10%
microorganisms are the most efficient: 40% |
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Term
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Definition
| the percentage of production transferred from one trophic level to the next. must always be less than production efficiencies because they take into account not only the energy lost through respiration and contained in waste, but also the energy in organic material in a lower trophic level that is not consumed by the next trophic level. generally only 10%, but range from 5-20%. generally, about 90% of the energy available at one trophic level is not transferred to the next. This loss is multiplied over the length of a food chain. |
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Term
| explain why worldwide agriculture could feed more people if all humans consumed only plant material |
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Definition
| Because trophic efficiency is so low, it would make sense to eat foods, such as plants, at lower trophic levels because less energy would be lost. For example, if we used the land we use to grow plant material for livestock to grow fruits and vegetables, we would have much more end food product. Plus, meat is not a renewable food, once you kill the animal you have a set amount of food. In contrast, an apple tree is constantly producing food and doesn't require as much energy to grow and mature as a cow does. |
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Term
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Definition
97% is in the ocean, 2% in ice, 1% available
essential to all organisms, and is usable mostly when in it's liquid form.
solar energy driving evaporation as well as condensation and transpiration by plants drive the cycle. |
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Term
| the draw the carbon cycle |
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Definition
carbon is essential to all organisms
used as CO2 by plants during photosynthesis and respiration and converted into organic molecules
most carbon is in sediments and rocks, dissolved in the ocean, in the soil, the atmosphere, and biomass on land.
photosynthesis is key to the carbon cycle, removing large amount of atmospheric CO2. This quantity is approximately equal to CO2 added to the atmosphere through cellular respiration. fossil fuels and volcanoes are also sources of CO2 |
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Term
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Definition
nitrogen is a part of amino and nucleic acids as well as proteins. It is often a limiting plant nutrient.
plants can use ammonium and nitrate and some organic forms, such as amino acids. bacteria can use organic forms, NH4, NO3, and NO2. Animals can only use organic forms.
most nitrogen is in the atmosphere as N2. other sources are soil, water, and biomass.
the major pathway of nitrogen into an ecosystem is nitrogen fixation, in which bacteria convert N2 to NH3 and NH4. these forms can then be synthesized into organic compounds and used by other organisms.denitrification involves bacterial conversion of nitrates or nitrites to nitrous oxide and nitrogen gas |
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Term
| draw the phosphorus cycle |
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Definition
phosphorous is a key element in nucleic acids, phospholipids, and ATP
the most important form is phosphate PO4 which is plants absorb and synthesize into organic compounds
most phosphorous is found in rocks of marine origin, but it is also found in the soil, dissolved in oceans, and in organisms.
weathering of rocks releases PO4, which leaches into the ground water. taken up by plants, converted into biological molecules, eaten by consumers, and returned to the soil as waste. |
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Term
| explain why toxic compounds usually have the greatest effect on top level carnivores |
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Definition
because compounds are not lost when they move through trophic levels, the accumulate each time they move up a level, often stored in fat cells.
ex- mercury in the ocean is consumed by plankton, a fish eats 5 plankton and now has 5 times the toxin that a single plankton did. a shark ate 10 fish, the shark would have 10 times the toxin concentration as the fish and 50 times the concentration as the plankton. |
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Term
| describe the causes and consequences of ozone depletion |
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Definition
| ozone is depleted by the release of CFCs into the atmosphere. the chlorine reacts O3 forming O2 and ClO. two ClO molecules then react forming Cl2O2. Solar energy then causes Cl2O2 to break down and O2 and two Cl atoms are formed. These Cl atoms then continue the cycle. This results in a thinning of the ozone layer and less protection from UV rays. An increase in UV exposure leads to DNA damage in plants and animals, causing a reduction in phytoplankton growth. More exposure to UV rays also leads to an increase in skin cancer and cataracts |
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Term
| effects of the increase of carbon |
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Definition
global climate change- altered precipitation patterns which lead to droughts, floods, and intense hurricanes. increased global temperature.
decease in arctic sea ice, as well as land ice
increase in sea level.
ocean acidification |
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