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38 Cards in this Set
- Front
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Define Species. |
A group of organisms that can interbreed to produce fertile offspring. Ex. while-tailed deer |
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What is an autotroph? Heterotroph? |
Autotroph: Organismscapable of making their own organic molecules as a food source from simpleinorganic molecules (CO2, H2O, sunlight) in the abioticenvironment (air, soil, sun). Ex. cyanobacteria Heterotroph: Cannotmake own food, must obtain organic molecules from other organisms. Ex.Zooplankton |
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What is the difference between consumers and decomposers? (Define each) |
Consumers: Anyorganisms that can’t synthesize their own food from inorganic material and relyon others for food. They ingest other organisms that are living/recentlykilled. Decomposers: Anyorganism that eats non-living organic matter; breaks down the body part of deadorganisms |
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What are they two types of decomposers? How do they differ? |
Detritivores: Ingestnon-living organic matter; eat dead leaves, feces or carcasses, ex. dung beetle Saprotrophs: Livein or on non-living organic matter, secreting digestive enzymes into in andabsorbing the products of digestion, ex. bacteria, fungi |
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What is the difference between a community and an ecosystem? |
Community: Agroup of populations living and interacting with each other in an area, Ex.soil community in a forest Ecosystem: A communityand its abiotic environment; where a group of interacting populations live. Ex.forest, pond, ocean |
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Abiotic vs. Biotic |
Abiotic: Non-livingcomponents of the environment (water, soil, air, minerals) Biotic: Livingcomponents of the environment, i.e. organisms |
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What are the four defining characteristics of a species? |
1. similar physiological, morphological characteristics (can be observed, measured) 2. Can interbreed, produce fertile offspring 3. Generally distinct from other species 4. Common phylogeny (family tree) |
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What is the outcome of members of different species mating? |
- When two differentspecies mate they usually don’t produce fertile offspring - If they successfullyproduce offspring, it’s called a hybrid - If one generation ofhybrids are produced, a second generation is very unlikely to occur - Ex. Female horse + maledonkey = mule |
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What is the effect and outcome of isolated populations? |
Effect: Ifa group of species becomes separated from the rest, two groups will evolvealong different evolutionary pathways due to different selective pressuresacting on each population. Two populations nowreproductively isolated due to water bodies, mountains, mating seasons, matingrituals, etc. Outcome: speciation, species can no longer interbreed successfully, new species result |
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Describe the systematic sampling technique. |
When measuringpopulation sizes, two techniques may be used: Random or Systematicsampling - Transect: line tracedfrom one environment to another. This line may be 10-50m and can be made usingrope, tape measure - Quadrat: placed down alongtransect and counting the organisms found within each quadrant - Useful to studyrelationships between distribution of organisms living along the transect (areastudied) |
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How is the supply of inorganic nutrients on Earth maintained? |
Supply maintained bynutrient cycling Ecosystems recycle elementsand compounds such as carbon, nitrogen, phosphorus, water, etc. necessary forlife to exist |
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What is the important of decomposers in an ecosystem? |
- They break down organicmolecules into inorganic molecules so they are available (not locked insidebodies/wastes of other organisms). - Decomposers recycle nutrients (inorganic)within an ecosystem, prevent waste from piling upMajor role in the formationof soil, a rich black layer called humus is made up of organic debris andnutrients released by decomposers |
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Why do ecosystems have the potential to be sustainable over long periods of time? |
Due to the recycling ofnutrients - Producers take in CO2and convert it into glucose. This simple sugar is then converted into complexcarbs. Consumers eat producersand digest complex compounds à amino acids, fattyacids, sugar for growth, repair, energy - When consumers die,their cells and tissues are broken down by decomposers and return mineral tothe soil. Producers absorb nutrientsfrom the soil (grow new sources of food), and the nutrient cycle is complete |
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What is a food chain? Food Web? |
Chain: Sequenceshowing feeding relationships and energy flow between species. The direction ofeach arrow shows which way the energy flows Web: An interconnectingseries of food chains. Since one organism ofteneats more than just one type f food, a simple food chain doesn’t tell the wholestory |
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What is chemical energy? What is it used for? |
Energyreleased from carbon compounds by cell respiration is used in living organismsand converted into heat Used for cell respiration |
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What is an energy pyramid? What is the correct unit of measurement? |
Diagrams that show howmuch energy flow through each trophic level in a community The correct unit for energyis kJm-2y-1 |
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What is a trophic level? |
Refers to an organism’sposition in a food chain Offer a way to classifyorganisms by their feeding relationships with other organisms in the sameecosystem |
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What is the importance of sunlight to ecosystems? |
Sunlightis the main source of energy for all life either directly or indirectly |
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What is the flow of energy in a food chain? |
Energy from sunlight to producers to primary consumers to secondary consumers to tertiary consumers etc. |
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What are the ways in which autotrophs, heterotrophs, and saprotrophs obtain energy? |
Autotrophs: Useexternal/non-organic energy sourceSome use light(photosynthesis), others used inorganic chemical reactions (chemosynthesis) Heterotrophs: fromother organisms by ingesting/consuming them Saprotrophs: fromnon-living organic matter, digest by extracellular means (digestive enzymes) |
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What is the movement of nutrients through an ecosystem? |
Nutrients are cycled andrecycled within an ecosystem: 1, Absorbedby producers 2. Movethrough food chain by digestion of organisms 3. Recycledfrom decomposition of dead organisms by decomposers 4. Nutrientsfrom weathering rocks also enter the ecosystem 5. Somenutrients lost by sedimentation 6. Supply of nutrients isfinite and limited hence it is recycled. |
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How is heat lost from organisms? How efficient are energy transformations then? |
- Heat generated by cellrespiration is lost to the environment, and once it leaves the organism’s bodyit cannot be used again as a biological energy resource. Unlike nutrients, energycannot be recycled - This is not usually aproblem – sun provides constant new energy to producers - Only chemical energy canbe used by the next trophic level - Only small amount ofenergy (10-20%) of the energy is available to use from the previous trophiclevel in a food chain, 90% lost at each level |
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What are the main reasons why so much energy is lost at every trophic level? |
1. Not the entire organism can be ingested 2. Not all food that is ingested can be absorbed and used 3. Some organisms die without having been eaten 4. Most energy is lost as heat (via cel respiration) in all trophic levels |
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Why are energy pyramids shaped the way they are? |
- Pyramids of energy arealways shaped with a large base, small top because each level is smaller thanthe one below it - This is because lessenergy flows through each trophic level in a community - Energy lost at each trophiclevel so less remains for the next level |
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Describe in detail the flow of energy through an ecosystem. |
- Energy enters fromsunlight - Producers capture thesunlight and have the largest energy available as they produce organicmolecules - Energy flows up in onedirection from one trophic level to the next in a community - Energy flows fromconsumers to other consumers, passes todecomposers in dead organic matter - Each level on thepyramid is about 10-20% of the size of the one below |
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What is the relationship between energy loss and the restriction go food chains and biomass of higher tropic levels? |
- Energy losses betweentrophic levels restrict the length of food chains to mostly four trophic levels (# of levels limited by how much energy enters the ecosystem, number of organisms in thechain, quantity of light available at the beginning) - The biomass of a trophiclevel is an estimate of the mass of all the organisms within that level. Lessbiomass at higher trophic levels because not all energy of biomass fromprevious levels is passed on |
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What are the four main greenhouse gases? Of them, which two are the most significant? Which two have less of an impact on the environment? |
Most significant: water vapour, carbon dioxide Less impact: methane, nitrogen oxides |
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What are two factors that determine the impact of a gas on the atmosphere? Use CO2 and CH4 to explain this. |
1. Itsability to absorb long-wave radiation (especially infrared heat)
2. Itsconcentration in the atmosphere: - CO2 is veryabundant making up 400ppm by volume of the atmosphere (0.04%), and has anestimated lifetime of 50-200 years - CH4 has 33times the effect of CO2 but is not very abundant because it has ashort lifetime of about 8-12 years (oxidizes more quickly)· |
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What type of radiation is emitted from the warmed Earth? |
- When sunlight touches anobject some light energy (short wavelength) is absorbed and converted into heatenergy (long wavelength) or infrared radiation, which is what the warmed Earthemits - This long wave radiationis then absorbed by greenhouse gases that retain the heat in the atmosphere |
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Outline the process of the NATURAL greenhouse effect. (6 steps) |
1. Sunlightenters Earth’s atmosphere as the gases of the atmosphere are transparent tolight 2. Mostof the sunlight is reflected off the surface of the Earth and travels back outof the atmosphere 3. Someof the light energy is transformed into heat energy and warms up oceans, forests, etc. which radiates much heat back to the atmosphere 4.Shortwave radiation hit’s the Earth’s surface and some is converted into long waveradiation. Some heat escapes into space but some is radiated back by greenhousegases 5. GHGsabsorb and retain some of the heat coming from the surface and trap it in theatmosphere 6. Endresult: atmosphere is warmer than outer space |
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What are the outcomes of increased concentrations of greenhouse gases? |
- Higher global averagetemperature - More frequent, intense heatwaves, drought, rain periods or flooding, tropical storms - Changes to oceancurrents - Climate pattern changes - Warming of arcticregions |
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Natural greenhouse effect vs. enhanced greenhouse effect |
- Concentrations of GHGsin the atmosphere are naturally low, preventing too much heat retention - Problem: rise in humanpopulation, human activity lead to increased concentrations of GHGs (consumers demand for food increases, sodoes excess production of waste gases) Since all 3 atmosphericgases have a high potential for absorbing heat, climate experts are concernedthat these gases are intensifying Earth’s natural GHE to where it is offbalance creating enhanced GHE, overall temps increase, leading toglobal warming - There is a directcorrelation between increasing atmospheric concentration of CO2 since start of industrial revolution 200 years ago and averageglobal temperatures, and corresponds with ice core data as well |
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What are the threats of ocean acidification to coral reef (from increasing concentrations of dissolved CO2)? |
- Research shows that by2100 coral reefs may erode faster than can be rebuilt which compromisesviability of ecosystems and about 1 million species that depend on this habitat - Marinecalcifying species (oysters, clams, corals) need to absorb carbonate ions from seawater tomake calcium carbonate in their skeletons - This is done byphotosynthesis through algae and sea grasses however low CO2 is alimiting factor of photosynthesis - The ocean absorbs about25% of the CO2 emitted into the atmosphere (thus when atmospheric CO2levels increase, levels in oceans increase as well) - Since the year 1800, pH ofseawater has fallen by 0.1pH (logarithmic, represents 30% increase in acidity) - Estimates of future CO2levels indicate that by 2100 seawater could be 150% more acidic to a level notseen for more than 20 million years |
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What is the precautionary principle? |
- Ethical theory whichsays that action should be taken to prevent harm even if there isn’t sufficientdata to prove that the activity will in fact have severe negative consequences à aka more good than harm - ifpeople wish to engage in an activity that may cause damage/changes in theenvironment, they first must prove it will not cause harm - Without this principle,industries and consumers tend to proceed with their activities until it becomesclear that harm is being done to the environment |
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How is the precautionary principle used as a justification for strong action in response to threats by the greenhouse effect? |
- advocates thatpreventative action should be taken NOW to reduce carbon emissions and GHGproduction before it is too late - Farmers, manufacturers,transportation providers wonder why they should invest $$$ in new techniquesthat reduce GHGs if scientists aren’t 100% sure how the GHE is going to harmthe environment - Ideally: consumers shouldbe allowed to choose products/services provided by ecologically mindedcompanies. If done at large scale, it would attract customers and companieswhich are not ecofriendly would be avoided and go out of business |
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How should we evaluate claims that humans are not causing climate change? What are examples of such claims? |
- Many claim that humanactivities aren’t causing climate change in the media, whether in newspapers,on TV or on internet - Important: realize thatnot all sources are trustworthy, and it is important to know the motivation ofthose publishing claims on either side of the debate - Examples: “Climate’schanged before” “It’sthe sun” “It’snot bad” “Thereis no consensus” |
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What are examples of human activities causing environmental changes? |
- CO2:transport that is based on burning fossil fuels in cars/trucks/dieseltrains/airplanes - CO2: otherhuman activities include deforestation, heating homes, purchasing goods/foodthat have long distance transport costs and/or grown out of season, commutingto work, etc. - CH4: increased meat consumption especially in theUS lead to increased in the number of cattle being raised, thus leads to largeamounts of methane escaping into the atmosphere - NOx: Burningfossil fuels (gasoline in cars), using catalytic converters in exhaust systems,organic and commercial fertilizers to help crops grow better, industrialprocesses (production of nitric acid) |
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Give one detailed example of a human activity that directly caused environmental changes. Include the activity, name of impact, mechanism of impact, and the environmental change. |
-Human activity: electricpower production - Name of impact: airpollution - Mechanism of impact:sulphur dioxide emission from coal burning power plants leading to acid rain - Environmental change: acidrain, which can lead to acidification of freshwater lakes, killing aquaticorganisms |
