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105 Cards in this Set

  • Front
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system
relationships amoung components that interact w/ & influence eachother
exchanging matter/energy/info

earth is made up of interacting systems
"systems science"
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)
common aspects of all systems:
feedback loops
hierarchy
dynamic equilibrium
emergent properties
closed/open system
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)
feedback occurs in:
cellular systems
organ systems
ecosystems
global "ecospheric" systems [biogeochemical cycles]
dynamic equilibrium
processes in a system move - and + directions at equal rates ---> the effects balance the system

**photosynthesis & respiration**
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
closed v open systems
closed : isolated/ self contained

open : exchanges energy/matter/info w/ other systems (real-world systems including earth)
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
ECOSPHERE
LITHOSPHERE [rock/sediment/soil]
+
HYDROSPHERE [all H2O]
+
ATMOSPHERE [air surrounding planets]
+
BIOSPHERE [biotic communities]
===================
ECOSPHERE

*sum of all living things & abiotic enviro interacting*
Ecosphere
v
Biosphere
Ecosphere = abiotic + biotic

Biosphere = only biotic
Community
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
Types of Symbiosis

(how communities are structured)
-mutualism (+,+)
-predation (+,-)
-parasitism (+,-)
-competition (-,-)
-commensalism (+,0)
-amensalism (-,0)
-neutralism (0,0)
ecological energetics
is about symbiosis (who eats who)
-food chains/ food webs

the balance between chloroplasts & mitochondria that drives a community/ an ecosystem
energy
measure of capacity of a system to do work
work
force through distance
Laws of Thermodynamics
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
energy from the sun powers the biosphere

which rays are "HEAT" rays?
INFRARED (IR) = "heat"
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
the reverse of photosynthesis =
aerobic respiration

C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + ENERGY

*respiration splits sugar molecules & releases chemical energy
**done in autotrophs & heterotrophs**
which rays of sun power the system?
VISIBLE LIGHT
380-750 nm

shorter wavelength (380 nm) = higher energy
longer wavelength (750nm) = lower energy
LEAF is the ORGAN
then...
ORGAN
-tissues
--cells
---organelles
----molecules
where is absorbtion of sunlight the lowest??
in the green/yellow spectra
(~500-600nm)

--GREEN (the color of the chlorosphere!) is the wasted light ---->reflected not absorbed
__ process in cells lead to ___ processes in the biosphere -->ecosphere
photosynthesis & respiration LEAD TO biogeochemical cycles
(CHNOPS etc)
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)
biogeochemical cycle
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***
Resevoir
the "pool" --- the largest collection of the material

(largest resevoir of C is in carbonate rocks)
Flux
the "flow" --- the movement of material from one resevoir to another

(atmospheric CO2--->biospheric CHO--->atmospheric CO2)
Residence Time
average amount of time molecule of particular element spends in a resevoir

(hours --> eons)
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
Water's Resevoirs
Oceans
Ice
Ground H2O
Surface H2O
Atmosphere
Biosphere

(most H20 is salty, most freshwater is frozen)
(biosphere= trivial resevoir)
Nutrients
elements/compounds organisms consume & require for nutrition & survival

*must cycle*
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
> 99% of atoms in life:
C
H
N
O
P
S
facts of the NITROGEN CYCLE
-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
Phosphorous cycle facts
-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
carbon cycle facts
-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
human impact on nitrogen
NOx produced by cars / fertilizers
-we've doubled amt of nitrogen in ecosphere
human impact on carbon dioxide
-increased by burning fuels & deforestation
-present concentrations highest
-burning carbon out of fossil fuels 60,000x faster than flux into fossil fuels(their formation)
ANTHRO-biogeochemical cycles
=includes human impact

biogeochemical cycles ARE BECOMING anthro-biogeochemcial cycles
factors influencing rate of photosynthesis?
1) light
---quality
---quantity
2)temperature
3)available raw materials
---CO2
---H2O
---Minerals
4)Plant Species
How to measure photosynthesis rate??
Land: HARVEST METHODS
Water: O2 PRODUCTION

& CO2 assimilation
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)
Net Primary Production of the Chlorosphere
Gross Production
- respiration (autotrophs)
==================
net primary production

*annual NPP = 8 x 10^18 kcal
Allocation of Earth's solar energy
40% reflected from atmosphere
10% absorbed by atmosphere
(50% gets through)
40% reflected from surface
10% absorbed by surface

left for chlorosphere < 1%
Land v Ocean NPP
continent area:ocean area ::
1:3
continent NPP:ocean NPP ::
3:1


Land Area: 26 %
Land NPP: 73 %

Ocean Area: 70 %
OCean NPP: 25%
Production increases with
MOISTURE

*Tropical rainforest has greatest NPP*
Phytomass
Plant Mass
Net Ecosystem Production (NEP)
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]
which biome has most littermass?
BOREAL FOREST (taiga/coniferous forest)

-littermass disproportionate to area

[moisture & temperature influence microbial activity]
"necrosphere"
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)
Food Webs
Energy flow in biotic communities

-largely about symbiosis, esp. predation & parasitism (+,-)
Predation
v
Parasitism
Predators feed on hosts & DO kill them

Parasites feel on hosts & DO NOT kill them
average # of trophis levels?
4 TROPHIC LEVELS

(steps that don't directly depend on the sun)

1*consumers
2*consumers
3*consumers
decomposers
pioneer of study of food chains?
ELTON
-elton's little green book (animal ecology)
Ecological Efficiency
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***
Components of Ecological INEFFICIENCY
-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
Implications of Ecological Inefficiency
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]
pyramids don't always have to be pyramids
(leaves --> bugs)

aka eltonian pyramids
energy pyramid
ALWAYS IN PYRAMID SHAPE
energy flows downhill
interspecific competition
-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)
Lotka-Volterra equations
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)]
competitive exclusion principle
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]
Non-resource factors influencing competition
-temp
-soil/water pH
-relative humidity
-salinity

(all non-consumable resources)
Enviro variability results in
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
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
Niche
v
Habitat
Niche: "profession" - role in the community
[lions kill zebras--lion niche shaped by others in community]

Habitat: "address" - living space
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
coexistence involving partitioning of resources
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]
n-dimensional hypervolume niche
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
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
character displacement
when shift in niches involves morphology, behavior, or physiology
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
functional response v
numerical response
functional response = relationship between rate of consumption & number of prey

Numerical response: increased consumption of prey = increased predator reproduction
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
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
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
aggregative response
the response of predators to move to areas of high prey density
-reason= predator pop grows slowly compared to prey pop
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
marginal value theorem
predicts length of time individual should stay in patch before leaving & seeking another
"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)
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)
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
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*
-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
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
consumption efficiency
ratio of ingestion to production

--defines amt of available energy being consumed
biogeochemical cycle
nutrients flow from nonliving to living and back to nonliving components in an ecosystem
two basic types of biogeochemical cycles:
1)gaseous
-

2)sedimentary
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***
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
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)
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]
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
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
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
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)
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
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
WATER CYCLE

(resevoir/fuction/special facts)
resevoir/fuction/special facts:

ocean / dispersal & medium / biosphere trivial in large scale cycle
CARBON CYCLE

(resevoir/fuction/special facts)
resevoir/fuction/special facts:

carbonate rocks(limestone dolomate) / in all organic compounds / __
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)
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)