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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$s!
.cientists use se(eral approaches to studyin%ecolo%y!
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"u$ans in/uence ecolo%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
)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!
.cientists use se(eral approaches to studyin%ecolo%y!
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"u$ans in/uence ecolo%ical syste$s!
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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 $atched to twi%color!
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Chapter 1 concepts
)colo%ical syste$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$s!
.cientists use se(eral approaches to studyin%ecolo%y!
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"u$ans in/uence ecolo%ical syste$s!
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)(olutionary patterns
#irst or%anis$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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)(olutionary patterns
@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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)(olutionary patterns
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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)(olutionary patterns
?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
$anyare plant mutualists!
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)(olutionary patterns
@ni$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
)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!
.cientists use se(eral approaches to studyin%ecolo%y!
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"u$ans in/uence ecolo%ical syste$s!
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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$ponents!
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Chapter 1 concepts
)colo%ical syste$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$s!
.cientists use se(eral approaches to studyin%ecolo%y!4
"u$ans in/uence ecolo%ical syste$s!
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"u$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