ecology lec12

7/25/2019 Ecology Lec12

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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
http://en.wikipedia.org/wiki/Floridahttp://en.wikipedia.org/wiki/Florida


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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!

ecology lec12

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