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69 Cards in this Set
- Front
- Back
Describe the soil horizons given in class.
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O horizon = organic matter, decomposing but not yet decomposed (i.e.
leaf litter, poo) microbial community A horizon = products of decomposition… CO2, Nitrates, Phosphates, nutrients BUT –maximum eluviation (leaching). Top of mineral soil B horizon = maximum illuviation –deposition of leached elements C horizon = underdeveloped mineral layer R horizon = bedrock layer |
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What is cation exchange capacity?
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• Measure of soils ability to absorb cations –most important nutrients are cations, organic matter increases CEC
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Why is soil pH important?
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pH affects nutrient availability
best for most crops is slightly acidic soils Very acidic – H binds to clay particles, displace nutrient cations which leach out Very alkaline – other cations (exchangeable bases) reduces CEC Nutrient cations bind too tightly to soil (polyvalent cations) but plants can’t take them up. |
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What are the water and nutrient holding capacities of different kinds of soils?
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Sandy soil = poor water & nutrient holding capacity
Silty soil = intermediate characteristics Clay soils = good water and nutrient |
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What’s a loam?
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Soil with a “good” balance of sand, silt, clay
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How are soil structure, texture, and porosity interrelated?
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Texture influences porosity by the relative amount of different sized particles (e.g. more clay = lower porosity
They all fit together as pieces into a whole that determines the amount of nutrients, water, and other products a soil can contain. |
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What are soil structure, texture, and porosity?
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Structure –physical arrangement of particle –affects porosity
Texture –relative proportions of different sized particles affects porosity Porosity –total volume of pores and pore size Influences gas exchange in soils (aeration) Affects H2O holding capacity |
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What are the components of soils?
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Complex of:
1. Parent material –mineral component (was rock) 2. Organic material –litter input (leaves, twigs); dead stuff; wastes = detritus 3. Air Spaces full of gases and/or water (atmospheric gases –nitrogen, oxygen, CO2) 4. Solutes –dissolved in the water 5. Living things –such as bacteria and fungi, symbionts, pathogens, parasite, herbivores |
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What are some physiological adaptations?
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heat shock proteins
can have alternative enzymes kick in can have alteration of the membrane lipids tiny leaflets: smaller surface area cool more readily |
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What are some leaf adaptations to hot/dry/sunny or moist/shady environments?
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Pubescence/color –reflective
Leaf Angle –vertical –less direct radiational loading Moist: large leaves cooled through transpiration |
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Review the factoids given in the soils lab (NOT the methods).
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Phosphates are given up in the soil but most are chemically bound and unavailable for plant uptake
Nitrogen from the atmosphere is the ultimate source of soil N, but much of it also comes from wet and dry atmospheric deposition and from decomposing organic matter such as leaves and animal detritus Plants can take up nitrates but NOT nitrites |
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What are the characteristics of mollisols, spodosols, alfisols, oxisols, entisols, and
aridisols? |
Alfisols –temperature deciduous forests; good O horizon; significant clay component; fertile soils
Spodosols – coniferous forests; very acidic; not very fertile Mollisols – grasslands –”best” agricultural soils; very thick layer of organic matter; annual plants and root turnover Oxisols – tropical rain forest oldest soils; not very fertile; most of the nutrients are held in the biomass; trees are evergreen (leaves aren’t dropped every year); massive leaching Aridisols – desserts; “bad” soils; very little organic input (not much there to die); high pH; any nutrients that are there are really tightly bound by soil and not readily taken up; caliche layer (calcium and other salts) because you have high evaporation and low precipitation Entisols – very young; underdeveloped; variable fertility |
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What defines a soil as being saturated, at field capacity, or at
wilting point? |
Saturated – all pore spaces full of water; not very good to have all the time because it creates anaerobic conditions in root zone
Field capacity – small pore spaces saturated; large have drained (percolation through soil) Wilting point – the water in the soil is held too tightly to be taken up Hygroscopic – hygroscopic coefficient –absorbed H2O @ 50% humidity |
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Why do soil porosity and texture matter?
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They matter because they determine the nutrient quality and holding ability as well as the water holding capacity
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What’s the main adaptation to cold?
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Tough needles (conifers)
Purposely loose water content (frost hardening) Halting metabolism |
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What is leaf characteristic dimension? What does it influence?
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size and shape influences formation of a boundary layer and a small boundary layer can cool more easily
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What conductances are important in transpiration?
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Stomatal conductance
Boundary layer conductance |
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What is transpiration and what is the driving force for transpiration?
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Evaporation from leaves
Vapor pressure deficiet of the air influenced by temperature and moisture; the hotter the more moisture it can hold |
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What are conduction and convection?
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Conduction –direct contact –one substance or another (Important in soil)
Convection –air flow (fluid) |
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What are the various components of the energy balance equation?
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Qnet = net radiation
QH = sensible heat –temperature QE = Latent heat –evapotranspiration cooling process Qs = storage –depends on tissue –laws of physics Qm = metabolic –negligible in plants Qcc o Conduction –direct contact –one substance or another (Important in soil) o Convection –air flow (fluid) |
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What is latent heat exchange and why is it important?
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Latent, or hidden heat determines level of evaporation and can affect energy balance/enzymatic activity.
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What are active, optimal, and lethal limits in terms of temperature?
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Active = Range of activity (metabolic)
Optimal = Best range for most metabolic activities Lethal = Compatible with life |
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What is osmoregulation and how does it help a plant deal with low soil moisture?
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Osmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. How does it help deal with low soil moisture?
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Describe various physiological, anatomical, and morphological adaptations and acclimations to low water availability.
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Drought Avoidance
Drought Deciduousness Drought Tolerance physiological anatomical/morphological phreatophytes root/shoot ratio leaf adaptations succulents sunken or encrypted stomata xylem modifications |
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Distinguish between aquatic plants, hygrophytes, mesophytes, xerophytes, and halophytes.
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Aquatic plants – submerged/floating –both
Hygrophyte –permanently moist/wet soil (like a bog) Mesophyte –wet/dry/wet often moist rarely super dry Xerophytes –prolonged dry periods Halophytes –saline soils (plants must overcome the soils tendency to hold onto water) |
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What are WUE’s various measures?
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Biomass/transpiration
Biomass/per amount of H2O applied (often used in agriculture) Yield/H2O applied (often used in agriculture) |
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What is water use efficiency?
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there is a trade off between closing stomata to conserve water and the need to take up CO2 for photosynthesis WUE is a measure of this trade off
• WUE = A/E (and others) o A is CO2 assimilation o E is evapotranspiration |
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What’s the relationship between VPD and humidity?
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VPD varies within the day and the season so it greatly affects humidity. Small changes in VPD = big changes in water density of the air.
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What is a boundary layer and what affects it?
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The Boundary layer is the still air around and underneath the leaf. Size and shape of the leaf determine the boundary layer. Big leaves vs. Fern.
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What’s the relationship between VPD and humidity?
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VPD varies within the day and the season so it greatly affects humidity. Small changes in VPD = big changes in water density of the air.
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What conductances are important in transpiration?
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Stomatal conductance
Boundary layer conductance |
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What is transpiration and what is the driving force for transpiration?
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Evaporation from leaves
Vapor pressure deficiet of the air influenced by temperature and moisture; the hotter the more moisture it can hold |
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How does water potential differ in the various components of the SPAC?
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Soil has the highest water potential
Plant –intermediate Air –lowest exponentially lower This is why water moves through plants w/o energy expenditure Water potential (Ψ) is expressed in units of pressure |
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What is the SPAC?
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(Soil Plant Air Continuum)
Soil has the highest water potential Plant –intermediate Air –lowest exponentially lower This is why water moves through plants w/o energy expenditure Water potential (Ψ) is expressed in units of pressure |
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What are (Water Potential) its components?
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Ψo = usually negative
Ψp = usually positive Ψm = usually negative (in soil) Ψg = usually negative (in soil) Ψo –osmotic –solute concentration in cells plants can digest this Ψp –pressure –turgor pressure Ψm –matric potential –how strong is soil’s hold on water Ψg –gravimetric –gravity’s pull on water towards earth More negative number = a drier, more water stressed plant Difference in potential energy between pure H2O and a solution |
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What's water potential?
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measure of water status
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Describe the characteristics that allowed plants to live on land and then move away from water to colonize the earth.
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Waxy cuticle
Vascular tissue (mosses lack these and will be restricted to environments close to water) Mycorrhizal associations Spread to diverse environments –pollen & seeds Ferns and etc… are limited to moist places because they don’t have pollen they have spores and swimming sperm |
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What are the ways that plants use water?
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Turgor pressure (helps tissue stand up)
Transpirational evaporative cooling –keep stomata open Most water taken up just passes through Reactant in photosynthesis |
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What is Plant Ecology?
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The study of the environment with respect to plants. duh!
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Components of the biotic environment?
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Reproduction, mutualism, seeds/pollen, mycorrhiza, competition for nutrients(The main focus of Ecology)
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Components of the abiotic environment?
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Soils, water, temp, CO2, light. All the most important factors with animals.
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Organizational hierarchy--
Organismal/individual |
The basic unit of ecology, identify mechanisms that give rise to diversity of life.
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Organizational hierarchy--
Population |
Groups of individuals occupying the same geographical location.
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Organizational hierarchy--
What is a Community? |
population + ecosystem = community
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Organizational hierarchy--
What is a System(s)? |
How yearly rainfall affects productivity, all biotic and abiotic elements in a given area.
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Organizational hierarchy--
What is Landscape Ecology? |
Ecosystems + communities = Landscape Ecology
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Scientific method what are the steps? 1-4
acronym O.Q.H.P.H. |
1 Observations
2 Questions 3 Hypothesis 4 Predicitons |
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Scientific method
acronym O.Q.H.P.H. #5 |
#5 Hypothesis testing
1)If experiment agrees with predictions, further hypothesis will be expanded and predicted scope of problem 2) If experiments are not consistent with the predictions, then conceptual model must be reconsidered. |
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3 Types of ecological research
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a) Controlled experiments
b) Natural experiments c) Observational experiments |
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Scale of research can be conducted in 2 ways.....
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a) Spatial (latitude, atmospheric moisture, position in forest)
b) Temporal (time of day, or season) |
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Specific Scale and Heterogeneity give rise to....
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Effective Ecological Research
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How does climate vary around Oklahoma?
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More rain = longer growing season, most --> least, SE --> NW. See precipitation data lab #1
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What is the main point of the light reactions of photosynthesis?
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6CO2+6H2O+light --> C6H12O6+6O2+ATP
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What is the main point of the Calvin Cycle (C3)?
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1) Fix CO2
2) Make simple sugars |
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Regarding the Calvin Cycle, what is used and what is produced?
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RuBP(5-carbon) + CO2, ATP +NADPH reduce CO2 to make Triose Phosphates(G3P's)
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What are the main factors that limit photosynthetic rate?
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1) Light
2) CO2 availability 3) Stomata closure 4) Temperature/enzymatic fluidity |
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How do these factors (photosynthetic rates) vary over time?
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Via seasons(temporal) and atmospheric CO2 availability. CO2 ppm .0035 --> .0037
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What are PAR and PPFD?
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Photosynthetically Active Radiation and Photosynthetic Photon Flux Density.
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What is light compensation point? vs. light saturation point(s)?
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LCP is the amount of light (PAR) at which net photosynthesis is zero. Carbon loss equals carbon uptake. 4-7p.m.
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What is light saturation point?
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The condition of maximum photosynthesis now only limited by dark reactions. 10a.m.-12
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High energy wavelengths are short or long?
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Short!
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Low energy wavelengths are?
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Long. Analogous to low hearing frequency.
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(PAR) photosynthetically active radiation is considered between __nm and __nm?
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400 nm & 700 nm.
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Name characteristics of Sun Leaves?
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1) Less surface area
2) Thicker (nm) 3) More stomata 4) Big investment in biomass (Think umbrella leaf!) |
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Name characteristics of Shade Leaves?
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1) Thin/Broad
2) Fewer stomata 3) More chlorophyll per cm2 4) Lower light saturation point |
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Adaptations to light levels include........
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1) Horizontal arrangement, receives mid-day sun.
2) Vertical arrangement, receives morning and evening sun. 3) Cupped arrangement, disperse light. 4) Solar Trackers, just plain cool! |
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Ohm's law =
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Current = Voltage/resistance
Conductance = 1/resistance |
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Driving Force =
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(Ca - Ci)
Ca = carbon atmospheric CO2 Ci = carbon internal CO2 |
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What is the driving force of CO2 uptake?
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Internal CO2 levels
remember Atmospheric - Internal = Driving Force (Ca - Ci) |