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100 Cards in this Set
- Front
- Back
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What do accessory pigments do?
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ex: chl b
- Broaden the spectrum used for PS |
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What are carotenoids used for?
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Some used for PS, or absorb excessive light that might damage the plant
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What happens when a pigment absorbs light?
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It goes from a ground state to an excited state - this is unstable
- When excited e- falls back to the ground state, photons are given off = fluorescence |
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What makes up a photosystem?
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- Rxn center complex surrounded by light-harvesting complexes - funnel the E of a photon to the rxn center complex
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What does a primary e- acceptor in the rxn center complex do?
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Accepts an e- from chl a
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What are the 2 types of photosystems?
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PS II
- Functions first and absorbs wavelengths of 680 nm PS I - Comes second and absorbs 700 nm |
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What are the 2 types of electron flow that can happen?
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Linear and cyclic
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What is the difference between linear and cyclic electron flow?
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Linear;
- Involves both photosystems and produces ATP and NADPH using light E Cyclic: - Uses only PS I and produces only ATP |
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What are the 3 processes contributing to the proton gradient?
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1) H+ from split H2O in thylakoid space
2) Transport of 4H+ from the stroma from the ETC 3) Removal of H+ from stroma in production of NADPH - Proton gradient can be used by ATP synthase to produce ATP from ADP + Pi |
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What is the sugar produced in the calvin cycle?
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G3P
- Calvin cycle must take place 3 times to produce 1 G3P |
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What are the 3 phases of the calvin cycle?
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- C fixation
- Reduction - Regeneration of the CO2 acceptor (RuBP) |
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What are the products of the light rxns?
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ATP and NADPH
- ATP: E source - BADPH: e- carrier These will be used in the calvin cycle |
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How is ATP produced?
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- Use ATP synthase - mb protein complex that synthesizes ATP from ADP + Pi
- Need E to do this - from proton gradient across the thylakoid mb |
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Where does the E come from to pump H+ into thylakoid space?
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E in e-'s coming down the ETC
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How does the e- in the ETC get its E?
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- Photons of light
- Funneled through pigments, eventually elevates e- from p680 to the primary e- acceptor |
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What is the source of the e- that receives E from a photon?
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Water
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What happens when plants close their stomata?
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Conserves water (prevents dehydration) but reduces CO2 and causes O2 to build up
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What is photorespiration in C3 plants?
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Alternative method of C fixation
- IN C3 plants initial fixation of CO2 forms a 3-C compound - Photorespiration - rubisco adds O2 instead of CO2 in the calvin cycle - no production of sugar, consumes O2 |
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What is photorespiration in C4 plants?
(monocots, grasses) |
- Incorporate CO2 into a 4C compound
- Use the enzyme PEP carboxylase - PEP carboxylase has a higher affinity for CO2 than rubisco does, and no affinity for O2 - Thses 4-C compounds are exported to bundle-sheath cells where they release CO2 that is then used in the calvin cycle |
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What is photorespiration in CAM plants?
(cacti) |
- Succulents use crassulacean acid metabolism (CAM) to fix
- CAM plants open their stomata at night, incorporating CO2 into organic acids - Stomata close during the day and CO2 is released from organic acids and used in the calvin cycle |
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What did the evolution of xylem and phloem allow for?
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The long-distance transport of water, minerals and products of pS
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Where are the products of PS moved to?
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Transported through phloem by the process of translocation to sinks
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What is phloem sap?
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Aqueous sol'n that is high in sucrose
- It travels from the sugar source (leaves) to a sugar sink (net consumer and storer of sugar) |
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What are the 2 ways sugars can move?
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By symplastic or both symplastic and apoplastic pathways
- Symplast - cytosol and plasmodesmata of living cells |
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What is the apoplast?
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- Pathway for sugar transport in plants
- Consists of everything external to the plasma-mbs - includes cell walls, extra-cellular spaces, and the interior of vessel elements and tracheids |
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What does the plasma mb permeability control?
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The short-distance movement of substances
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What do proton gradients allow for the movement of?
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Other substances through active transport
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What does phloem loading require?
(sugar transport) |
- Active transport
- Proton pumping and cotransport of sucrose and H+ |
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What is osmosis?
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Diffusion of water across a mb
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What is water potential?
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- A measurement that combines the effects of solute [ ] and pressure
- Higher physical pressure - push water - Higher solute [ ] - pull water - Water flows from high water potential to low water potential |
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What are the effects of solutes on water potential?
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- Solutes have a negative effect on water potential by binding water molecules
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What are the effects of pressure on water potential?
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- Positive P has a positive effect on water potential by pushing water
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What are the effects of both solutes and P on water potential?
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- Solutes and positive P have opposing effects on water movement
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What are the effects of negative water potential on water potential?
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Negative P (tension) has a negative effect on water by pulling water
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What does efficient long distance transport of fluid require?
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Bulk flow - the movement of a fluid driven by P
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What do water and solutes move together through?
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Tracheids and vessel elements of xylem and sieve-tube elements of phloem
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What is translocation?
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Mechanism of bulk flow by positive P
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What are the 4 steps to translocation?
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1) loading of sugar
- Sugar is loaded into sieve-tube (active transport with H+) - Reduces water potential 2) Water moves into sieve tube via osmosis (uptake of H2O) - Generates positive P - Forces movement of sap through sieve tube 3) Unloading of sugar - At sink by diffusion 4) Water is recycled - moves into xylem |
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At sink, what kind of diffusion moves sugar to cells?
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Facilitated diffusion
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What is the endodermis?
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Inner most layer of the cortex - layer of cells - surrounds the vascular cylinder
- Selective passage of minerals into the vascular tissue |
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How can water cross the cortex?
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symplast or apoplast
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What does the waxy casparian strip of the endodermal wall do?
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Blocks apoplastic transfer of minerals from the cortex to the vascular cylinder
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What does the endodermis do?
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Regulates and transports needed minerals from the soil into the xylem
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Where do water and minerals move from and to?
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From the protoplast of endodermal cells into their cell walls
- then enter tracheids and vessel elements |
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What is transpiration?
(Bulk flow transport via xylem) |
The evap of water from a plant's surface
- Water is replaced by the bulk flow of water and minerals called xylem sap - Water molecules are attracted to each other through cohesion (makes it possible to pull a column of xylem sap) |
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What do root cells do at night?
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Continue pumping mineral ions into the xylem of the vascular cylinder, lowering the water potential
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What generates root pressure?
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Water flowing in from cortex
- Can result in guttation - the release of water droplets on the tips of leaves |
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What are the 3 steps to transpirational pull?
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1) water vapour in the airspaces of a leaf diffuses down its water potential gradient and exits leaf via stomata
2) water is lost from mesophyll cells into air space in leaf 3) this draws water from xylem into surrounding cells |
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What are the effects of large SA and high area in leaves?
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- Volume ratios in leaves increase PS and increase water loss through stomata
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What helps balance water conservation?
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Guard cells help balance water conservation with gas exchange for PS
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What opens and closes the stomata?
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Changes in turgor P
- When turgid (excess water and stiffer), guard cells bow outward and part between - Then opens (plagid, droopy) - Due to the uptake and loss of K+ ions by the guard cells |
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When are stomata generally open and closed?
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Open during the day and closed at night to min water loss
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What trigger the stomatal opening at dawn?
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- Light
- CO2 depletion - An internal "clock" in guard cells (all euk organisms have an internal clock) |
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What are arcadian rhythms?
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24 hour cycles
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What are xerophytes?
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Plants adapted to arid climates
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What are adaptations of herbivores?
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- Giraffe tongue
- Flattened teeth - Cows digestive system - Beaks |
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What does the phloem allow for?
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Rapid electrical communication between widely separated organs
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What is the Regina soil?
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- Clay
- High nutrient [ ] - K+ - Alkaline |
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What is soil separated into?
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Layers called soil horizons
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What makes up the top soil?
(A horizon) |
- Consists of mineral particles, living organisms and humus - the decaying organic matter
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What are loams?
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The most fertile top soils - contain equal amounts of sand, silt and clay
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What prevents cations from being leached out of the soil?
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Adhering to negatively charged soil particles
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What happens during cation exchange?
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Cations are displaced from the soil particles by other cations
- Displaced cations enter soil sol'n and can be taken by plant roots |
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What does soil pH affect?
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Cation exchange and the chemical form of minerals
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In what pH are cations more available?
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In slightly acidic soils, as H+ ions displace mineral cations from soil particles
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What is an essential element?
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Required for a plant to complete its life cycle
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What is hydropanic culture used for?
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To determine which elements are essential
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What are macronutrients?
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Plants require these in relatively large amounts
ex: C, H, O for carbphydrates, N for proteins |
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What are micronutrients?
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Plants need these in small amoutns
- Used for enzymes |
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What is meneral deficiency?
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Phosphate, potassium and nitrogen
- Causes colouration in plants |
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What helped plants colonize land?
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Mutualisms with fungi
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Define ecology
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Study of the interactions between organisms and the env
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What is organismal ecology?
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Studies how an organism's structure, physiology and behave (animals) meet env'al challenges
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Define biogeography
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Global and regional patterns of distribution of organisms
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What 2 factors determine distribution of sp?
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Biotic (living factors) and abiotic (non-living)
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What are biotic factors that affect distribution of sp?
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- Predation
- Competition - Dispersal ability - Behav (animals) |
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What are abiotic factors that affect distribution of sp?
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- temp
- water - sunlight - wind - rocks and soil |
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What are biomes?
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- The major ecological associations that occupy broad geographic regions of land or water
- biotic and abiotic det the nature of biomes |
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What are terrestrial biomes?
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- Fir tree in northern conifers forest
- Dandelion in man biomes |
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Define pop'n ecology
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Is the study of pop'ns in relation to env
- Density and distribution - Age structure - Pop'n size |
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Define pop'n
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A group of indiv's of the same sp living in an area
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Define density
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Number of indiv's per unit area or volume
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Define dispersion
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Is the pattern of spacing among indiv's
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What is clumped dispersion?
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Indiv's aggregate in patches
- may be influenced by resource ability and behav |
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What is uniform diversity?
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- Indiv's are evenly dispersed
- affected by competition - Territoriality (in animals) |
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What is random dispersion?
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Position of each indiv is independent of other indiv's
- Occurs in the absence of strong attractions or repulsions |
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Define demography
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The study of the vital statistics of a pop'n and how they change over time
- Death and birth rates |
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What is a survivorship curve?
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A graphic way of representing death rate vs age
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What are the 3 types of survivorship curves?
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Type I: low death rates during early and middle life then increase in older age groups (humans)
Type II: death rate constant over organisms life span (ground squirrel) Type III: high death rates for young, then slower death rates for survivors (oyster) |
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Define carrying capacity
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(K) Is the max pop'n size that the env can support
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What is the exponential graph?
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J shaped
- cannot be supported for long |
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What is the logistic graph?
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S - shaped
ex: paramecia |
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What are limits on human pop'n size?
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- Human carrying capacity?
- Natural resources - Food - Farmlands - Space - Buildup of wastes |
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Define community ecology
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Deals with the whole array of interacting species in a community
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Define community
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a group of pop'ns of different species in an area
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What are interspecific interactions?
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Relationships between sp in a community
ex: competition, predation, symbiosis (-/- interaction) - occurs when sp compete for a resource in short supply |
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What is competitive exclusion?
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Local elimination of a competing species
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What is the competitive exclusion principle?
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2 sp competing for the same limiting resource cannot coexist in the same place
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Define predation
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(+/- interaction) one species (predator) kills and eats the other (prey)
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Define herbivory
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(+/- interaction) a herbivore eats parts of a plant or alga
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