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ECOLOGY
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What is Ecology?
The term ecology or oekologie was coined by the German biologist Ernst
Haeckelin 1866, when he defined it as "the comprehensive science of the
relationship of the organism to the environment"Haeckel did not elaborate on theconcept, and the first significant te!tbook on the sb#ect $in 1895% $together with the first
niversity corse% was written by the Danish botanist, Eugenius Warming &or this
early work, Warming is oten i!entiie! as the oun!er o ecology
"co#e o Ecology
Ecology is the scientiic stu!y o the !istribution an!
abun!ance o lie an! the interactions bet$een organisms
an! their en%ironment&
a& 'nteractions !etermine !istributionan! abun!anceo organisms&
($o main themes in ecology are)
* Where !o organisms li%e? + Why?
* o$ many organisms are #resent? + Why?
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Ecology $as historically an obser%ational science, oten
!escri#ti%e natural history&
Organism
En%ironment
-iotic com#onents
Li%ing actors,
Other Organism
.biotic com#onents
/on*li%ing actors,
(em#&
Water
/eutrients, etc&
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'n ecosystem has abiotic and biotic components(
')*+T* components(
- .olar energyprovides practically
all the energy for ecosystems
- *norganic sbstances, eg, slfr,boron, tend to cycle throgh
ecosystems
- +rganic componds, sch asproteins, carbohydrates, lipids,
and other comple! molecles,
form a link between biotic and
abiotic components of thesystem
)*+T* components(
-The biotic components
of an ecosystem can be
classified according to
their mode of energyac/isition
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-*n this type of classification, there are(
'totrophs
and
Heterotrophs
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- 'totrophs $0selfnorishing% are called
primary prodcers
- 2hotoatotrophsfi! energy from the snand store it in comple! organic
componds
- $0 green plants, algae, some bacteria%
0hoto*autotro#hs
sim#le
inorganic
com#oun!s
com#le
organic
com#oun!s
light
6+3$gas% 4 6H3+$li/id% 6H13+6$solid% 4 6+3$gas%$5ight chlorophyll%
$137 k9:mol glcose%6!
$;
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hemoatotrophs$chemosynthesi=ers% are bacteria
that o!idi=e redced inorganic sbstances$typically slfrand ammonia componds%and prodce comple! organic
componds
com#le
organic
com#oun!s
oygen
Chemoautotro#hs
chemoautotro#hsre!uce!
inorganic
com#oun!s
y!rogen suli!e chemosynthesis(
CO32 O32 3" C3O 2 " 2 :3O
;#ur#le sulur bacteria 1 an! a31> 1
*nterspecific competition is aggressive and ltimately one poplation wins, while
the other is driven to e!tinction The winner depends pon which has the starting
advantage
Case ''', '@) a13 < 1 an! a31> 1 or a13> 1 an! a31< 1
*nterspecific competition of one species dominates the other, so the species with
the strongest competition always drives the other to e!tinction
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''& Aactors aecting the !istribution o organisms
* -iogeogra#hy is the stu!y o #ast an! #resent !istribution
o in!i%i!ual s#ecies&
/eotro#icor /eotro#ical=one is one of the eight terrestrial eco=ones This eco=one
incldes .oth and entral 'merica, the >e!ican lowlands, the aribbean islands, and
sothern &lorida, becase these regions share a large nmber of plant and animalgrops
The ?earctic eco=one covers most of
?orth 'merica, inclding Greenland
and the highlands of >e!ico
2hysically, the 2alearctic is the largesteco=one *t incldes the terrestrial
ecoregions of Erope, 'sia north of the
Himalaya foothills, northern 'frica, and the
northern and central parts of the 'rabian
2eninsla
The Orientmeans "the
East" *t is a traditional
designation for
anything that belongs
to the Eastern world or
the &ar East, inrelation to Erope
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.& "#ecies !is#ersal contributes to the !istribution o
organisms
Dis#ersal reers to the #rocess o !istribution oin!i%i!uals $ithin geogra#hic #o#ulation boun!aries&
Buestion) 's the !istribution o a s#ecies limite! by
!is#ersal, i&e& by mo%ement o the organisms?
.ns$er can be obtaine! by trans#lant e#eriments&
' the trans#lant is successul, then the organisms ust
ha%ent reache! the target area&' the trans#lant is not successul, then other actors
limit the !istribution o the organisms, such as
com#etitors, lac o a oo! source, etc&
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-& -eha%ior an! habitat selection contribute to the
!istribution o organisms
1& Organisms may not occu#y all #otentially suitable habitat&Why?
a& E%olution !oesnt lea! to #erect organisms&
b& E%olution is an ongoing #rocess& En%ironments
change, but it taes a $hile or organisms to res#on!&
C& -iotic actors aect !istribution
1& Organisms reuire! or #otential community members to
coloni>e may be lacing&
* 0ollinators, #rey, #re!ators that limit com#etition
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D& .biotic actors aect !istribution
1& .biotic actors o interest inclu!e)
* (em#erature ;range rom F to 5 C+P?'>*.(
Energy can be converted from one form to another, bt cannot be created or destroyed
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5aws Governing Energy hanges
Second Law of Thermodynamics
In every transformation some ener!y isconverted to heat ("ower #ua"ity)
$ou cannot brea% even in terms ofener!y #ua"ity
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Energy flow
.implistically(
This pattern of energy flow among different organisms is the
TD+2H* .TDQTQDEof an ecosystem
heat
0ro!ucers Consumers
Decom#osers
heat
Ecosystem Aunction
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Ecosystem Aunction
H1& Energy lo$ in an ecosystem is re#resente! bya oo! $eb&
The amont of energy available to the organisms at eachtrophic level decreases as one moves p the food chain
since R
-energy is lost as heat and
- organisms se energy to sstain themselves
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-ecause the amount o energy !ecreases at each
successi%e tro#hic le%el, the number o organisms also
!ecreases
Only a##roimately 1FI o the energy is transerre! to the
net tro#hic le%el&
"o, are there more #ro!ucers or consumers on Earth?
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Energy and biomass pyramids
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2yramid of energy-
' pyramid of energy depicts the energy flow,or prodctivity, of each trophic level
- e to the 5aws of Thermodynamics, each
higher level mstbe smaller than lower levels,
de to loss of some energy as heat $via
respiration% within each level
#ro!ucers
herbi%ores
carni%ores
Energy lo$ in )
2 id f b
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2yramid of nmbers
- ' pyramid of nmbers indicates the
nmber of individals in each trophic level
- .ince the si=e of individals may vary
widely and may not indicate the
prodctivity of that individal, pyramids ofnmbers say little or nothing abot the
amont of energy moving throgh the
ecosystem
H o #ro!ucers
H o herbi%ores
H o carni%ores
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2yramid of standing crop
- ' pyramid of standing crop indicates how mch biomass
is present in each trophic level at any one time
- 's for pyramids of nmbers, a pyramid of standing crop
may not well reflect the flow of energy throgh the
system, de to different si=es and growth rates oforganisms
biomass o #ro!ucers
biomass o herbi%ores
biomass o carni%ores
;at one #oint in timeined for prodction of fertili=er
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The 2hosphors ycle
Driven by physica" forcesDriven by physica" forces
.lfr ycle
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.lfr ycle- slfr is released as rocks erode and plants
assimilate this
- >ostly fond nder grond like phosphors
- H3. is released by decomposers and dringvolcanic erptionsV some H3. in soil isconverted into slfr by aerobic bacteriaand plants assimilate this
-
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5imiting &actor 2rinciple5imiting &actor 2rinciple
- Too much or too little of any bioticToo much or too little of any bioticfactor can limit or prevent growth of afactor can limit or prevent growth of a
population, even if all other factors arepopulation, even if all other factors areoptimal for that population.optimal for that population.
- Single factor most over-abundant orSingle factor most over-abundant or
deficient in an ecosystem determinesdeficient in an ecosystem determinespresence/absence of specificpresence/absence of specificplants/animals.plants/animals.
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. .uatic biomes co%er about J5I o the earths surace
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.& .uatic biomes co%er about J5I o the earth s surace
* Wetlan!s
* Laes
* i%ers, streams
* 'nterti!al >ones
* Oceanic #elagic biome
* Coral rees
* -enthos
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-& (errestrial biomes
* (ro#ical orest
* "a%anna * Desert
* Cha#arral
* (em#erate grasslan!
* (em#erate !eci!uous orest * Conierous orest
* (un!ra
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( i l A t @ ti l t tii ti ith t i
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(ro#ical Aorest) @ertical stratiication $ith trees in
cano#y blocing light to bottom strata& =any trees
co%ere! by e#i#hytes ;#lants that gro$ on other #lants
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(em#erate Deci!uous Aorest) =i!*latitu!es $ith mo!erate
amounts o moisture, !istinct %ertical strata) trees,
un!erstory shrubs, herbaceous sub*stratum& Loss olea%es in col!, many animals hibernate or migrate then&
Original orests lost rom /orth .merica by logging an!
clearing&
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Conierous orest) Largest terrestial biome on earth, ol!
gro$th orests ra#i!ly !isa##earing, usually recei%es lots
o moisture as rain or sno$&
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(un!ra) 0ermarost ;0ermanent ro>en groun!