Ricklefs Lecture Ppt Ch01-3

7/23/2019 Ricklefs Lecture Ppt Ch01-3

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The Economy of Nature7th edition

Lecture PowerPoint

Chapter 1

Introduction: Ecology,Evolution, and theScientic Method

Rick Relyea Robert Ricklefs

2014 by ! "! #ree$an and Co$pany


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hat is ecolo%y&

Ecologyis the scienti'c study of the abundance anddistribution of or%anis$s in relation to other or%anis$sand en(iron$ental conditions!


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Chapter 1 concepts

)colo%ical syste$s e*ist in a hierarchicalor%ani+ation!)colo%ical syste$s are %o(erned by physical

and biolo%ical principles!

,i-erent or%anis$s play di(erse roles inecolo%ical syste$s!

.cientists use se(eral approaches to studyin%ecolo%y!

"u$ans in/uence ecolo%ical syste$s!

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Chapter 1 concepts

)colo%ical syste$s e*ist in a hierarchicalor%ani+ation!

1)colo%ical syste$s are %o(erned by physical

and biolo%ical principles!2,i-erent or%anis$s play di(erse roles inecolo%ical syste$s!


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)colo%ical syste$s

iolo%ical entities that ha(e their own internalprocesses and interact with their e*ternal surroundin%s

3ndi(idual

Population

Co$$unity

)cosyste$

iosphere

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3ndi(iduals

Individual:the $ost funda$ental unit ofecolo%y!

3ndi(iduals acuire nutrients and ener%y5

and produce waste!

Species:indi(iduals that are capable of interbreedin%or share %enetic si$ilarity!

6his de'nition is not uni(ersal there are $any

de'nitions of species!

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Populations

Population:indi(iduals of the sa$especies li(in% in a particular area!

oundaries can be natural 8e!%!5 forest

ed%es9 or political 8e!%!5 state lines9!

Abundance is the total nu$ber of indi(iduals!

Densityis the nu$ber of indi(iduals per unit area!

Compositionis the $akeup in ter$s of a%e5 %ender5 or%enetics!

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Co$$unities

Community:Populations of speciesli(in% to%ether in a particular area!

oundaries are not always ri%id5 and $ay

co(er s$all or lar%e areas!

3ncludes $any types ofinteractions5 such aspredation and co$petition!

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)cosyste$s

Ecosystem: co$$unities of lor%anis$sinteractin% with their nonli(in% physicaland che$ical en(iron$ents!

Research is focused on $o(e$ent ofener%y and $atter between physical andbiolo%ical co$ponents!

6his includes the :/ow; of $aterial fro$ :pools; of

ele$ents5 such as carbon5 o*y%en5 hydro%en5nitro%en5 and phosphorus!

oundaries are often not distinct!

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6he biosphere

iosphere: all ecosyste$s on )arth!

,istant ecosyste$s are linked to%etherby e*chan%es of wind and water and bythe$o(e$ent of or%anis$s!

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.tudyin% ecolo%y at di-erent

le(elsIndividual approach:


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Chapter 1 concepts





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>o(ernin% principles of ecolo%y

?atter and ener%y cannot be created or destroyed5but can chan%e for$ 8i!e!5 law of conser(ation of$atter rst la! of thermodynamics9!

)colo%ical syste$s %ain and lose $atter and ener%y!

@ dynamic steady state occurs when %ains andlosses are in balance!

>ains Losses

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)(olution

Phenotype: an attribute of an or%anis$ 8e!%!5beha(ior5 $orpholo%y9!

"enotype:the set of %enes an or%anis$ carries

deter$ines an or%anis$=s phenotype!

Evolution: a chan%e in the %enetic co$position of apopulation o(er ti$e!

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)(olution

Natural selection:@ chan%e in the freuency of %enes in a populationthrou%h di-erential sur(i(al and reproduction ofindi(iduals that possess certain phenotypes!

Three re#uirements1! 3ndi(iduals (ary in their traits!2! 6raits are heritable!! Aariation in traits causes so$e indi(iduals to e*perience

hi%her ftness8sur(i(al and reproduction9!

3ndi(iduals with better 'tness will pass $ore copies oftheir %enes to the ne*t %eneration5 and that

phenotype will co$e to do$inate!

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)(olutionNatural selection: E$ample

Caterpillars with bodycolor that better $atches

the twi% are less likely tobe eaten!

3f color is heritable5

subseuent %enerations ofcaterpillars will ha(e $oreand $ore indi(idualsbetter $atched to twi%color!

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Chapter 1 concepts





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)(olutionary patterns

#irst or%anis$s wereprokaryotes,or sin%leBcelled bacteria andarchaea without distinctor%anelles!Prokaryotes can utili+e

sources of ener%y that $ostother or%anis$s cannot5 suchas 2and "2. %as!

Cyanobacteria can

photosynthesi+e!


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@t so$e point5 one bacteriu$en%ulfed another bacteriu$!

6he en%ulfed bacteriu$beca$e a mitochondria5 and

this ancestor%a(e rise to all eukaryotes5oror%anis$s with distinct cellor%anelles!

?itochondria e(ol(ed intophotosynthetic chloroplasts!6hese or%anis$s increased theabundance ofo*y%en in the at$osphere5

allowin%


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Protistsare eukaryotes thatinclude proto+oa5 so$e al%ae5and sli$e $olds!

.o$e protists can %row (erylar%eand look like lar%e plants8e!%!5 kelp9!


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?ostfun%iha(e hyphaethate*tract nutrients fro$ dead orli(in% tissues!

6hey secrete acids5 anden+y$es di%est foode*ternally!

?any are deco$posers and

$anyare plant mutualists!


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@ni$alsplay a wide ran%e ofrolesin ecolo%ical syste$s!

6hey rely on the consu$ptionof other or%anis$s forresources!


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Cate%ori+in% species based on ener%ysource

ProducersEor autotrophsEcon(ertche$ical ener%y into resources!

ConsumersEor heterotrophsE

obtain their ener%y fro$ otheror%anis$s!

Mi$otrophs can switch betweenbein% producers and consu$ers!

Scavengers consu$e deadani$als!

%etritivores break down deador%anic


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6ypes of species interactions

Predation: when an or%anis$ kills and consu$es anindi(idual!

Parasitism: when one or%anis$s li(es in or on

another or%anis$!

&er'ivory: when one or%anis$ consu$es producers!

Competition: when two or%anis$s that depend onthe sa$e resource ha(e a ne%ati(e e-ect on eachother!Mutualism: when two species

bene't fro$ each other!

Commensalism: when twospecies li(e in closeassociation and one recei(es a

bene't5 whereas the other is


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"abitats and niches

&a'itat: the place5 or physical settin%5 where anor%anis$ li(es!,istin%uished by physical features5 such as do$inantplant type!

E$amples: #reshwater5 $arine5 coastal5 strea$s5 forests5deserts5 %rasslands!

"abitat types o(erlap and absolute distinctions rarely

e*ist!

Rain forest.trea$ 6ropical %rassland


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"abitats and niches

Niche: the ran%e ofabiotic and bioticconditions an or%anis$can tolerate!

o two species ha(ethe sa$e nichebecause each hasuniue phenotypes that

deter$ine theconditions it cantolerate!

E$ample: ,i-erent insects

prefer to feed on di-erent


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Chapter 1 concepts





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6he scienti'c $ethod4


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6he scienti'c $ethod

&ypotheses: ideas that potentially e*plain arepeated obser(ation!

@ particular hypothesis can rarely be con'r$edbeyond a doubt!

Predictions: state$ents that arise lo%ically fro$hypotheses!

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?anipulati(e e*peri$ents

Manipulative e$periments:where a hypothesis istested by alterin% a factor hypothesi+ed to be thecause of a pheno$enon!

Treatment: the factor that we want to $anipulate in

a study!

Control: a treat$ent that includes all aspects of ane*peri$ent e*cept the factor of interest!E$ample: Researchers want to test ifbirds are an i$portant factor in

deter$inin% the nu$ber of insects onoak trees!

6hey $anipulate the presence of birdsby placin% ca%es around oak trees!

.o$e trees were left unca%ed as

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?anipulati(e e*peri$ents

E$perimental unit: the obFect to which we apply a$anipulation!

(eplication: bein% able to produce a si$ilaroutco$e $ultiple ti$es 8i!e!5 the nu$ber of

e*peri$ental units per treat$ent9!

(andomi)ation: a reuire$ent for $anipulatione*peri$ents e(ery e*peri$ental unit $ust ha(e aneual chance of bein% assi%ned to a particular

treat$ent!

)*peri$ental units $ay

be natural 8e!%!5 lakes9or arti'cial 8e!%!5$icrocos$s95 and $ay(ary in si+e by se(eralorders of $a%nitude!

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@lternati(e types of e*peri$ents

Natural e$periments: an approach to hypothesistestin% thatrelies on natural (ariation in theen(iron$ent to test a hypothesis!

Mathematical models: representations of a syste$

with a set of euations that correspond tohypothesi+ed relationships a$on% the syste$=sco$ponents!

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Chapter 1 concepts




.cientists use se(eral approaches to studyin%ecolo%y!4



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"u$an in/uence on ecolo%icalsyste$s


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"u$an in/uence on ecolo%icalsyste$s

)n(iron$ents do$inated by hu$ans 8e!%!5 cities5far$s9 are also ecolo%ical syste$s hu$ans dependon the proper functionin% of these syste$s!

"u$ans consu$e $assi(e a$ounts of ener%y and

resources5 and produce lar%e a$ounts of waste!

"reenhouse gases: co$pounds in the at$ospherethat absorb infrared heat ener%y e$itted by )arth

and then e$it so$e of the ener%y back toward )arth!"i%h a$ounts of these %ases can increase a(era%e)arth te$peratures!

6hanks to ecolo%ical studies5 there are $any successt i f t i t d ti

Ricklefs Lecture Ppt Ch01-3

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