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105 Cards in this Set
- Front
- Back
system
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relationships amoung components that interact w/ & influence eachother
exchanging matter/energy/info earth is made up of interacting systems |
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"systems science"
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ecosystem ecology
--the study of the arrangement & relations of between parts that connect them as a whole --reductionist (study of parts to understand whole system) --hierarchical organization [simple to complex] (atoms-molecules-cells-tissues-organs-individuals-populations-communities-ecosystems-ecosphere) |
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common aspects of all systems:
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feedback loops
hierarchy dynamic equilibrium emergent properties closed/open system |
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feedback systems
(+)&(-) |
feedback(output serves as input)
(+)=accellerating feedback (-)=corrective=stabilizing feedback (-)=individuals [basic unit of ecology]= produces homeostasis by too hot = sweat, too cold = shiver (+)moves system farther in SAME direction (magnifies effects & destabilizes the system) |
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feedback occurs in:
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cellular systems
organ systems ecosystems global "ecospheric" systems [biogeochemical cycles] |
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dynamic equilibrium
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processes in a system move - and + directions at equal rates ---> the effects balance the system
**photosynthesis & respiration** |
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systems have
EMERGENT PROPERTIES: |
properties you can't see just by looking at system's parts
(tree is individual, habitat, CO2 sink)==>system of systems w/i a system |
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closed v open systems
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closed : isolated/ self contained
open : exchanges energy/matter/info w/ other systems (real-world systems including earth) |
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ecosystem has:
(is) |
1)biotic community
2)abiotic enviro 3)linked by mineral cycles 4)powered by energy flow *arbitrary*by chance*where you define them*basic study unit of systems ecology* *ecosystem from ecologist standpoint is basic unit of nature*1935 concept *ecosystem is the FUNCTIONAL (performing) unit of ecology (not simply structural) *pond, jar of pondwater = ecosystem (a sample of the ecosphere* *a concept, or CHUNK Of the ecosphere, NOT a specific place |
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ECOSPHERE
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LITHOSPHERE [rock/sediment/soil]
+ HYDROSPHERE [all H2O] + ATMOSPHERE [air surrounding planets] + BIOSPHERE [biotic communities] =================== ECOSPHERE *sum of all living things & abiotic enviro interacting* |
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Ecosphere
v Biosphere |
Ecosphere = abiotic + biotic
Biosphere = only biotic |
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Community
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Community = individuals interacting w/individuals of another species
**the biotic component of an ecosystem** -structured by symbiosis [interactions between species] =squirrels + trees -any patch in the landscape or the whole landscape can be considered a community *generalizations--not absolute *change through time [ecological succession] *change through levels of organization [atoms-cells-tissues-individuals..] =BIOTIC COMMUNITY =LIVING component of ecosystem *also arbitrary like ecosystems |
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Types of Symbiosis
(how communities are structured) |
-mutualism (+,+)
-predation (+,-) -parasitism (+,-) -competition (-,-) -commensalism (+,0) -amensalism (-,0) -neutralism (0,0) |
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ecological energetics
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is about symbiosis (who eats who)
-food chains/ food webs the balance between chloroplasts & mitochondria that drives a community/ an ecosystem |
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energy
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measure of capacity of a system to do work
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work
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force through distance
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Laws of Thermodynamics
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1)energy is neither created nor destroyed (law of conservation
2)energy transfers are never 100% efficient --- when energy is transferred some is lost as heat *free energy of a system is continually decreasing *entropy (measure of unusable energy) continually increasing ENERGY FLOWS DOWNHILL water flows downhill arrow in ecosystem diagram points downhill |
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energy from the sun powers the biosphere
which rays are "HEAT" rays? |
INFRARED (IR) = "heat"
|
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photosynthesis is the reaction that powers the biosphere
in presence of chlorophyll (catalyst) & sunlight (energy)..... |
6 CO2 + 6 H20 = C6H12O6 + 6 O2
water + carbon dioxide --> sugar + oxygen |
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the reverse of photosynthesis =
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aerobic respiration
C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + ENERGY *respiration splits sugar molecules & releases chemical energy **done in autotrophs & heterotrophs** |
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which rays of sun power the system?
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VISIBLE LIGHT
380-750 nm shorter wavelength (380 nm) = higher energy longer wavelength (750nm) = lower energy |
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LEAF is the ORGAN
then... |
ORGAN
-tissues --cells ---organelles ----molecules |
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where is absorbtion of sunlight the lowest??
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in the green/yellow spectra
(~500-600nm) --GREEN (the color of the chlorosphere!) is the wasted light ---->reflected not absorbed |
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__ process in cells lead to ___ processes in the biosphere -->ecosphere
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photosynthesis & respiration LEAD TO biogeochemical cycles
(CHNOPS etc) |
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chlorosphere
|
global sum of chloroplasts
-"new term" emphasizes that macroscopic (huge) production takes place on micoscopic (tiny) scale *the productive "skin" of the earth *earth's biotic, dynamic, photochemical transducer *mechanism to power the biosphere ***10 cm to 10s of meters high*** ***shortgrass prairie to deciduous forest*** NOT VERY THICK [land LAI {leaf area index} ~ 5 ... water = scum] ~~~~maybe 2.5 mm thick =FRAGILE (tho still HUGE) *its effectiveness (productivity) varies from place to place (geographically) (LAI = avg # leaves covering particular area of earth's surface during growing season) |
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biogeochemical cycle
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movement of matter(atoms/molecules) between biotic & abiotic components of the ecosphere
*studied at ecosystem level (subsets of ecosphere), then scaled up to ecosphere (global scale) ***most biogeochemical cycles are basically nutrient cycles*** |
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Resevoir
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the "pool" --- the largest collection of the material
(largest resevoir of C is in carbonate rocks) |
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Flux
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the "flow" --- the movement of material from one resevoir to another
(atmospheric CO2--->biospheric CHO--->atmospheric CO2) |
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Residence Time
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average amount of time molecule of particular element spends in a resevoir
(hours --> eons) |
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Hydrologic Cycle
key pts |
**major resevoir = OCEANS
**transpiration dominates lands **evaporation dominates waters **cycle is global scale **H20's residence time in the atmosphere ~ 5 days |
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Water's Resevoirs
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Oceans
Ice Ground H2O Surface H2O Atmosphere Biosphere (most H20 is salty, most freshwater is frozen) (biosphere= trivial resevoir) |
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Nutrients
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elements/compounds organisms consume & require for nutrition & survival
*must cycle* |
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BIOLOGICAL CHEMICALS:
1)carbohydrates 2)fats 3)proteins 4)amino acids |
1)carbohydrates
---glucose monomers ---built of C H O ---fuel & storage 2)fats ---fatty acids & glycerol monomers ---built of C H O ---fuel, storage, membranes 3)proteins ---amino acid monomers ---built of C H O N S ---structure, catalyst, molecular transport 4)amino acids ---nucleotide monomers ---built of C H O N P ---info storage, catalyst, energy transformations |
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> 99% of atoms in life:
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C
H N O P S |
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facts of the NITROGEN CYCLE
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-huge atmospheric resevoir
-microbial mediation of cycle -marine cycling ca 20X marine fixation -terrestrial cycling ca 10X terrestrial fixation **lots of recycling** -~residence time of fixed (reduced) N in biosphere = 625 yrs -N fixation by lightening = 1/7 annual fixation -fertilizers produce ca 140x10^9 T/yr |
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Phosphorous cycle facts
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-most abundant in rocks
--weathering releases phosphate into H20 --plants take up phosphates in H20 ----->return it to soil when they die -phosphates dissolved can be deposited as sediments -bones high in P (fossils) -no stable gaseous component @ earth surface temps --->addition of P to land is slow --->not well distributed -humans accelerated P transfer from rocks to soil/plants |
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carbon cycle facts
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-driven by photosynthesis & respiration
--largely run the ecosphere -most carbon in rocks -most carbon not in rock is in ocean -more carbon in atmosphere than in plants -more carbon in soil than in land plants -6x more carbon in fossil fuels than in atmosphere =8x more carbon in fossil fuels than in living plants than |
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human impact on nitrogen
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NOx produced by cars / fertilizers
-we've doubled amt of nitrogen in ecosphere |
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human impact on carbon dioxide
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-increased by burning fuels & deforestation
-present concentrations highest -burning carbon out of fossil fuels 60,000x faster than flux into fossil fuels(their formation) |
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ANTHRO-biogeochemical cycles
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=includes human impact
biogeochemical cycles ARE BECOMING anthro-biogeochemcial cycles |
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factors influencing rate of photosynthesis?
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1) light
---quality ---quantity 2)temperature 3)available raw materials ---CO2 ---H2O ---Minerals 4)Plant Species |
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How to measure photosynthesis rate??
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Land: HARVEST METHODS
Water: O2 PRODUCTION & CO2 assimilation |
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C-3
v C-4 Plants |
C-3 Plants = "cool season"
(photosynthesize more w/ cooler temps & less sunlight) C-4 Plants: "warm season" (photosynthesize more w/much warmer temps & more sunlight) |
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Net Primary Production of the Chlorosphere
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Gross Production
- respiration (autotrophs) ================== net primary production *annual NPP = 8 x 10^18 kcal |
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Allocation of Earth's solar energy
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40% reflected from atmosphere
10% absorbed by atmosphere (50% gets through) 40% reflected from surface 10% absorbed by surface left for chlorosphere < 1% |
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Land v Ocean NPP
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continent area:ocean area ::
1:3 continent NPP:ocean NPP :: 3:1 Land Area: 26 % Land NPP: 73 % Ocean Area: 70 % OCean NPP: 25% |
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Production increases with
|
MOISTURE
*Tropical rainforest has greatest NPP* |
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Phytomass
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Plant Mass
|
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Net Ecosystem Production (NEP)
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Gross Productions
-respiration (autotrophs) =================== Net Primary Production (NPP) -respiration (heterotrophs) =================== Net Ecosystem Production (NEP) (community perspective... communites include heterotrophs too--not just autotrophs (NPP)) *Tends toward 0!! =over time P~R =balance between production/consumtion (in MATURE ecosystems) [producers produces bonds in carbohydrates; consumers consume carbohydrates] |
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which biome has most littermass?
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BOREAL FOREST (taiga/coniferous forest)
-littermass disproportionate to area [moisture & temperature influence microbial activity] |
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"necrosphere"
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sphere of "dead stuff"
-thin layer -the garbage / community inefficiency -short lived periods when P:R>1 -when photosynthesis got ahead of respiration --->disequilibrium (somehting adapts to clean up leftovers) |
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Food Webs
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Energy flow in biotic communities
-largely about symbiosis, esp. predation & parasitism (+,-) |
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Predation
v Parasitism |
Predators feed on hosts & DO kill them
Parasites feel on hosts & DO NOT kill them |
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average # of trophis levels?
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4 TROPHIC LEVELS
(steps that don't directly depend on the sun) 1*consumers 2*consumers 3*consumers decomposers |
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pioneer of study of food chains?
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ELTON
-elton's little green book (animal ecology) |
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Ecological Efficiency
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output/input
-accounts for energy flow between trophic levels -% energy captured by one trophic level thats able to be passed on to the next ***10% ECOLOGICAL EFFICIENCY*** ***100g plant = 10g bunny = 1g wolfe*** |
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Components of Ecological INEFFICIENCY
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-movement
-active transport against membranes -respiration (2nd law of thermodynamics) (every process besides energy for growth & reproduction) ===>only energy available to next trophic level is that invested in growth & reproduction |
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Implications of Ecological Inefficiency
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1)Only ~4 Trophic Levels on average
2)not many big fierce animals (they're 5th-6th order consumers) 3)biological magnification is frequent [magnification of DDT in food chain increases as go up thru chain] |
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pyramids don't always have to be pyramids
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(leaves --> bugs)
aka eltonian pyramids |
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energy pyramid
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ALWAYS IN PYRAMID SHAPE
energy flows downhill |
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interspecific competition
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-both species affected adversely (-,-)
-2+ species seek resource in short supply 6 types: -1-consumption (consume shared resource) -2-preemptive (occupation precludes occupation of other species) -3-overgrowth (literally grows over the other) -4-chemical interactions (toxins inhibit/kill other) -5-territorial (behavioral exclusion) -6-encounter (negative meeeting) |
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Lotka-Volterra equations
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describe 4 possible outcomes of competition
[competitive exclusion outcomes] 1)species A succeeds 2)species B succeeds [coexistence outcomes] 3)unstable equilibrium (species that was abundant at offset succeeds) 4)stable equilibrium (both species coexist at lower pop levels [studied by Gause (paramecium studied by Park (Tribolium) studied by Tilman (Synedra)] |
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competitive exclusion principle
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2 species w/exact same ecological requirements can't coexist
(if species A increases a little bit faster than B it drives be to extinction) [assumes species have exact same requirements & enviro conditions remain constant] |
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Non-resource factors influencing competition
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-temp
-soil/water pH -relative humidity -salinity (all non-consumable resources) |
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Enviro variability results in
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changing competitive advantages allowing coexistence of competitors
--->no species will reach sufficient density to displace its competitors --->enviro variation allows competitors to coexist -can also limit pop density (periods of drought etc) -can drop species below carrying capacity -resources abundant enough to decrease/eliminate competition **contant conditions would exclude one another |
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fundamental niche
v realized niche |
fundamental niche: pre-competition
realized niche: post-competition -the portion of the fundamental niche that species actually uses **niche overlap doesn't always mean extensive competition--resource could be abundant |
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Niche
v Habitat |
Niche: "profession" - role in the community
[lions kill zebras--lion niche shaped by others in community] Habitat: "address" - living space |
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Competitive Release
|
when species expands its niche with removal of a competitor
(when species moves away from competitors or a competitor is removed) ex. increased availability of krill to seals when whale numbers decreased |
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coexistence involving partitioning of resources
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coexistence associated w/some degree of niche differentiation
--differences in range of resources used --differences in enviromental tolerances coexistence by partitioning is --useing differend kinds/ sizes of food --feed at different times/in different areas --require different proportions of nutrients --different tolerances of light/shade **each species exploits a portion of resource unavailable to others --->leads to hutchinson's hypervolume *resource partitioning results from physiological, morphological, or behavioral adaptations [outcomes of interspecific competition in the past] |
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n-dimensional hypervolume niche
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Hutchinson's QUANTIFIED revised version of Elton's niche
-multi-dimensional (greater than 3 dimensions) -what we live in -LENGTH x WIDTH x DEPTH x TIME -compeetitive interaction in hypervolume can be less than in one gradiant alone |
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competition influencing natural selection
|
characteristics enabling an organism to reduce competition increase fitness ---> influencing evolution of characteristics
when species are SYMPATRIC (live together) -->shifts in beak sizes -->shift in feeding niches =CHARACTER DISPLACEMENT |
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character displacement
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when shift in niches involves morphology, behavior, or physiology
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reason predator prey populatoins OSCILLATE
|
as predator pop increases comsumes larger # of prey
-until prey pop declines -prey pop no longer supports large predator pop -predators face food shortage -predator pop declines sharply -prey increases -causes predator pop to increase again =MUTUAL POPULATION REGULATION =regulation for prey through mortality =regulation for predators through reproduction |
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functional response v
numerical response |
functional response = relationship between rate of consumption & number of prey
Numerical response: increased consumption of prey = increased predator reproduction |
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Type I Functional Response
|
-linear (# of prey taken increases w/prey density)
-characteristic of passive predators [spiders] -all time allocated for feeding spent seaching --no handling time |
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Type II Functional Response
|
(looks like carrying capacity)
-rate of predation increases in decelerating fashion up to maximun rate (attained at some high prey density) -time divided into searching & handling -DECLINING MORTALITY RATE OF PREY W.INCREASING PREY DENSITY (as captured prey increases handling time increases & decreases time available for further searching) -MOST COMMON FOR PREDATORS |
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Type III Functional Response
|
(looks like S)
-rate prey are consumes is low at first -then increasing as rate of predation approaches max value -regulates prey density bc initial rate of prey mortality increases with prey density factors leading to type III response:: -available of cover to escape from (limited cover protects prey at LOW prey densities only) -predators search image (if new species appears its not yet recognized as food by predator) -"switching" (turning to more abundant prey species for food)-depends on food preference |
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aggregative response
|
the response of predators to move to areas of high prey density
-reason= predator pop grows slowly compared to prey pop |
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Optimal foraging theory
|
-natural selection should favor efficient foragers
-individuals that max their energy/nutrient intake per unit of effort -time spent foraging balanced against defense time, avoiding predators, searching for mates, caring for young |
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marginal value theorem
|
predicts length of time individual should stay in patch before leaving & seeking another
|
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"predator defenses"
-defenses used against predators |
"PREDATOR DEFENSES" by prey:
-chemical defenses -cryptic coloration (blend into background) -warning coloration -batesian mimicry (evolved coloration mimics warning coloration) -mulerian mimicry (similar color paterns of venomous species) -protective armor -behavioral defenses (warning calls) -predator satiation (timing reproduction so abundant offspring) 2 types: -1-permanent/constitutive defenses (fixed features) -2-induced (chemical & flight defenses) |
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predator's evolution of hunting tactics
|
-ambush (lying in wait -low success rate -minimal energy)
-pursuit (minimal search time -long pursuit time) -stalking (quick attck -great search time -low pursuit time) -cryptic coloration -deception (resembling prey) |
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evolution of grasses
+other plant defenses |
meristems (source of new growth) near ground
-grazers feed on older tissue -most grasses benifit from grazing -hairy leaves, thorns, spines, low nutrient content |
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productivity equations
|
(the rate at which organic matter is created by photosynthesis)
energy over time: kcal/m^2/yr units organic matter over time: g/m^2/yr NOT BIOMASS (biomass= amt present at given time [g/m^2]) *NPP can be measured by change in biomass over time* |
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-highest NPP?
-most productive waters? |
-highest NPP in equatorial zone (combination of warm temps and precipitaion supports high rates of photosynthesis and leaf area)-tropical rain forest
-also more H2O in soil = greater standing plant biomass -most productive waters = shallow waters at coast (great transport of nutrients from bottom sediments to surface water & receive nutrients from neighboring terrestrial ecosystems) *primary productivity increases with phosphorous concentration |
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2 major food chains in a given ecosystem:
|
1)grazing food chain
-energy source = living plant biomass -1st level consumers= cattle, rabbits, insects -unidirectional 2)detrital food chain -energy source = dead organic matter (detritus) -1st level consumers usually snails, beetles, millipedes, fungi -not unidirectional |
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consumption efficiency
|
ratio of ingestion to production
--defines amt of available energy being consumed |
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biogeochemical cycle
|
nutrients flow from nonliving to living and back to nonliving components in an ecosystem
|
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two basic types of biogeochemical cycles:
|
1)gaseous
- 2)sedimentary |
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Nutrient Cycling
process |
plants take up nutrients
-->become incorporated in their tissues (organic matter) -die --dead organic matter returned to surface -decomposers transform organic nutrients into mineral form -->once again nutrients (in mineral form) available for plant uptake ***process = internal cycling*** |
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Decomposition Processes
|
decomposition = breakdown of chemical bonds formed during construction of tissues
-includes leaching, fragmentation, digestion, excretion -microflora group = bacteria & fungi are most commonly associated w.decomposition -microbivores feed on bacteria & fungi *decomposers derive energy & nutrients from consumption of organic compounds |
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Factors influencing decomposition
|
microbial decomposers use carbon in dead organic matter as energy source
-glucose/simple sugars easily broken down & high quality carbon source -cellulose (cell wall constituents) = intermediate quality -lignins = low quality & decompose the slowest -temp & moisture greatly influence decomposition -->highest decomposition rate = under moist warm conditions (variation in decomp rates relate directly to climate) |
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Net Mineralization Rate
|
the net release of nutrients into soil/H2O during decomposition
Mineralization Rate - Immobilization = net mineralization rate [mineralization = decomposers breaking down dead organic matter transforming nutrients into inorganic form] [immobilization: decomposers re-use some of nutrients they've produced, reincorporating them into organic form] |
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decomposition in open water / oceans
|
dead organisms = particulate organic matter (POM) drift down
--->constantly ingested, digested & mineralized until most is humic compounds by time it reaches bottom |
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rate of nutrient cycling
|
directly related to rates of primary productivity (nutrient UPTAKE) & decomposition (nutrient RELEASE)
enviro factors that effect PP & decomp will affect rate of cycle indirectly |
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seperation between primary production & decomposition
|
terrestrial ecosystems: plants bridge the gap
aquatic: actual physical seperation liminiting nutrients in surface water -->in winter thermocline breaks down allowing for mixing of nutrients into surface waters -->leads to seasonal patter of productivity |
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CARBON CYCLE
|
-inseperable from energy flow (productivity usually measured w/ carbon)
-assimilated by plants -consumed by heterotrophs -released by both through respiration -mineralized by decomposers -accumlated into standing biomass -withdrawen into long reserves -swamps marshes--carbon circulates slowly forming natural gasses -builds up at night & during winter (out of growing season) |
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NITROGEN CYCLE
|
-fixation by bacteria
-ammonification [breakdown of amino acids] by decomposers -nitrification [oxidation of ammonnia to nitrates]] -denitrification [reduction of nitrates to gaseous nitrogen] -major resevoir = atmosphere |
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PHOSPHOROUS CYCLE
|
-*no significant atmospheric pool
-major resevoir = rocks -terrestrial cycles follow normal route -aquatic cycles = 3 states [1.particulate organic phosphorus; 2.dissolved organic phosphates; 3.inorganic phosphates] -nearly all phosphate in terrestrial ecosystem derived from weathering of minerals |
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WATER CYCLE
(resevoir/fuction/special facts) |
resevoir/fuction/special facts:
ocean / dispersal & medium / biosphere trivial in large scale cycle |
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CARBON CYCLE
(resevoir/fuction/special facts) |
resevoir/fuction/special facts:
carbonate rocks(limestone dolomate) / in all organic compounds / __ |
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NITROGEN CYCLE
(resevoir/fuction/special facts) |
resevoir/fuction/special facts :
atmosphere / proteins (structure & function of life) / stongly bonds as N2; cycle dependent on specialized microbes |
|
PHOSPHOROUS CYCLE
(resevoir/fuction/special facts) |
resevoir/fuction/special facts :
phosphate rock / dna, rna, atp / heavy element (no gaseous compound @ earth surface temps-->no atmospheric component of cycle) |
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NUMBERS:
0 1 4 10 |
0 = ~NEP
1 = % efficiency of chlorosphere @ capturing solar energy 4 = kcal of energy in 1 g carbohydrate 10 = % ecological efficiency in energy transfer (also 10 kcal in 1 g of fat) |
|
BOTTOM-UP
v TOP-DOWN food chains |
BOTTOM-UP: populations at any given trophic level are controlled by populations at trophic level below [diversity of carnivores essentially controlled by herbivores & controlled by primary producers]
TOP-DOWN: predator poulations control the diversity of prey species including primary producers (ex. limiting herbivores can allow for more plant growth) |