Ecology Exam 2
Terms
undefined, object
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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
- nutrients flow from nonliving to living and back to nonliving components in an ecosystem
- 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 - 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 - 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 -
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)