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How is population growth and size influenced? |
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Definition
Births and immigration increase population size Deaths and emigration decrease population size. |
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How can we use per capita growth rate(r)? |
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Definition
We can use it to predict population size changes. |
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True or false?In exponential growth per capita growth rate(r) is constant. |
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Definition
True. # of individuals added to the population at any one time is proportional to the size of the population at the start of the inertval. |
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List the formulas used for Exponential growth. |
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Definition
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What factors limit population growth? |
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Definition
Predation, limited resources, available space, disease, natural disaster. |
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Definition
The carrying capacity: the maximum amount of individuals a single environment can sustain. Represents the interplay between the functional requirements of indidviuals for growth and reproduction and environmental resources such as food and space availability. |
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What is happening at the following stages of the logistic growth graph: (K-N)/K=1, (K-N)/K=0.5,(K-N)/K=0. |
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Definition
(K-N)/K=1: few parents, lots of resources, gradual increase of population (K-N)/K=0.5: sharp increase in reproduction, less resources but still enough, stable so far. (K-N)/K=0: growth rate slows down, competition for resources, population begins to decrease. |
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What factors keep populations below K? |
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Definition
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When can a population increase Rmax? |
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Definition
When the pop. is small and there are lots of resources available. |
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What does the flat bottom of the Logistic growth curve reflect? |
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Definition
- Few parents, small population(N), High Ro |
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What does the top flat curve reflect? |
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Definition
Large population(N), low reproductive rate(Ro). |
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What does the logisitc growth model of sheep populations suggest? |
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Definition
That populations react to changes in the environment. |
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List 5 Density Dependent factors that influence Populatio Growth. |
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Definition
Predation, limited resources, available space, disease and any biotic factors. |
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List 2 Density Independent factors that influence Population growth. |
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Definition
Natural disaster, any abiotic factors(climate change) |
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In a graph showing the effect of precipitation levels on a population of sparrows: would the graph be showing density dependent or independent changes? |
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Definition
Density independent. Drought= abiotic. |
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Define Intraspecific and Interspecific |
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Definition
Intraspecific: competition between populations of the same species. Interspecific: Competition between different populations of different species. |
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True or false? both organisms and ecosystems are open systems. |
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Definition
True! Both matter and energy cycle through organisms and ecosystems. |
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What is the difference between primary producers and primary consumers? |
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Definition
Primary producers: Autotrophs, need energy from the sun. Plants. Primary consumers: Herbivores. They eat primary producers. |
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True or false? Nutrients only cycle through biotic systems. |
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Definition
False!! They cycle through abiotic and biotic. Carbon cycle, phosphorous cycle... |
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Explain what type of organisms are in the first trophic level and what they do. |
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Definition
Primary prdoucers: Photosynthetic organisms. They fix inorganic nutrients(C,N,P,O...) into organic molecules. |
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Define Primary Productivity |
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Definition
The rate at which biomass is produced. |
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Explain the units, what PP tells us and how it's measured. |
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Definition
Units: Amount of C fixed in a certain area per unit time. (kJ/Km2/year) Tells us how much energy is captured by an ecosystem. Using a sample of land. (Spatial and Temporal rate) |
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What is Gross Primary Productivity? |
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Definition
Total amount of CO2 fixed into organic molecules per unit time and unit area. |
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What is Net Primary Productivity? And what does it tell us? |
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Definition
What the producer makes minus what the producer uses itself. The amount of energy biomass production. Tells us how much energy is available for the consumers. |
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Write the process of GPP. |
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Definition
CO2->GPP->Leaves->Respiration. (CO2 is fixed in leaves and then is respirated) |
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Show the calculation for NPP |
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Definition
NPP- GPP-Ra(respiration of autotrophs. |
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What factors contribute to an ecosystem's PP? |
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Definition
Temperature: Increase in Temperature= Increase in PP Precipitation: Increase in Precipitation= Increase in PP. Until there is too much precipitation then it plateaus and decreases. |
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What factors contribute to terrestial producer's PP? |
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Definition
Nitrogen is essential for plant growth and chlorophyll content. |
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What factors contribute to aquatic producer's PP? |
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Definition
Phosphorous is a limiting nutrient. Increase in phosophorous=Increase in algae and surface plants. |
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Explain what type of organisms are in the second trophic level and what they do. |
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Definition
Primary consumers(herbivores): They eat the organic molecules made by the primary producers. Primary consumers won't be able to eat all producers and won't be able to assimilate everything it eats. |
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Term
What is Secondary production? |
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Definition
Secondary production is new biomass production. Secondary Production= personal growth. Egrowth. |
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What are Secondary/tertiary.etc Consumers? and what do they do? |
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Definition
Carnivores: consume organic molecules made by primary consumers. Won't be able to eat all primary consumers and won't be able to assimilate everything it eats |
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Term
What are Detritivores/Decomposers? What do they do and how? |
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Definition
Organisms that consume waste and dead organic matter of primary producers, primary consumers, etc. They return nutrients(matter) to soil. Decomposition is mostly through bacteria. |
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Term
Forces Regulating Trophic Structure: Explain Bottom-up Control. |
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Definition
Resources abundance regulates trophic structure. Energy in each trophic level is determined by the energy in the lower trophic level. |
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Forces Regulating Trophic Structure: Explain Top-Down Control. |
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Definition
Predation regulates trophic structure The energy in each trophic level is determined by the energy in the higher trophic levels. Driven by predators. |
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Term
What percent of energy is expected to be passed on to the next trophic level? |
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Definition
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Term
What is a trophic cascade? Example? |
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Definition
When a predator is removed from an ecosystem it causes a change in the lower trophic levels. Removal of hawks->Increase in foxes->Decrease in lemmings->Increase in plants. |
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Term
What is a keystone species? Example? |
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Definition
Important part of the community. Small in size but large in impact. Sea otters eat sea urchins. and sea urchins eat kelp that make cover for fish. |
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What happens if there are no more keystoners? |
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Definition
Absence of keystoners changes the ecosystem and its' composition completely. |
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True or false? Earth is an open system. |
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Definition
False. In nutrient cycling Earth is a closed system. |
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What 2 forms do elements cycle through and are they ever lost? |
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Definition
Biotic and Abiotic forms. They are never "lost" hence the word cycle. |
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Elements required by organisms are called? |
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Definition
Nutrients. They're good for you lolololol. |
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What are the 2 main nutrient cycle pathways? |
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Definition
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What are the 4 nutrient reservoirs? Give a brief description of each. |
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Definition
Short Term Organic: frequent cycling, living organisms, detritus. Short Term Inorganic: N(NO3), P(PO4), H2O, O2, CO2 Long Term Organic: Do not cycle: Fossil C=coal, oil.. Long Term Inorganic: Sedimentary rocks, carbonates |
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What 2 process occur between Long term inorganic and Short Term Inorganic? |
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Definition
LI->SI= Weathering SI->LI= Sedimentation |
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What 2 processes occur between Short Term Organic and Short Term Inorganic? |
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Definition
SO->SI= Decomposition or Disassimilation SI->SO= Assimilation |
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List the 2 types cyles for gaseous and non gaseous nutrients. |
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Definition
Local:Sedimentary, closed system Global: Gaseous, open system |
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What are the Biogeochemical cycles associated with Local and Global cycles? |
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Definition
Local: P. K, Fe, Ca, Na Global: C, N, O, S, H |
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Explain how C is the unit of energy currency in ecosystems. |
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Definition
Organic compounds of carbon are the form in which energy is transferred between trophic levels. |
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True or False? C is the most abundant element in organisms. |
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Definition
True!! Approxiamately 50% dry mass. |
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How does C cycle itself through ecosystems? |
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Definition
It moves between organic and inorganic C compounds. |
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In the short term Carbon cycle: What are the annual oscillations on atmospheric CO2 caused by? |
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Definition
Assimilation( photosynthesis) and disasimilation(respiration and decomposition) |
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Term
During the winter time in the northern hemisphere why is there an increase in atmospheric carbon? |
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Definition
Carbon isn't taken in by plants and carbon is still being released by plant respiration and decomposition |
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During the winter time in the Southern Hemisphere: what is happening? |
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Definition
The reverse is seen compared to the northern hemisphere. Places near the equator have less seasonality. |
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Term
What is happening in the spring time in the northern hemisphere? |
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Definition
Decrease in Carbon concentration in atmosphere. Increase of photosynthesis by plants. |
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Term
What is the cause of the continual increase in CO2 in the atmosphere? |
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Definition
Anthropogenic: change in environment due to human activity. |
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What is the Keeling Curve? |
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Definition
Y axis: CO2 concentration X axis: months of the year. |
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List the CO2 sources and CO2 sinks. |
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Definition
CO2 Sources: Fossil fuel burning, deforestation(tropics), deforestation(outside the tropics) CO2 sinks: Ocean(largest), Land(second largest), atmosphere |
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Term
What does a decrease of pH in the ocean indicate? |
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Definition
Ocean acidification. An increase in bicarbonate formation There is less carbonate Carbonate is needed to make shells and coral reef. |
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Term
What organisms are key to the survival of coral? |
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Definition
Invertebrates(polyops) and Algae(Zooxanthellae) |
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How do ecosystems differ? |
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Definition
Net primary productivity Efficiency of energy flow Nutrient availability |
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