3/1/15%1%Ecology'Study%of%the%rela2onships%of%organisms%to%one%another%(bio2c)%and%to%the%environment%(abio2c)%%%%Biosphere%Ecosystem%Community%Popula2on%Organism%(Individual)%Interac2ons%between%%bio*c%and%abio*c%factors%determine%the%distribu*on%%and%abundance%of%organisms%Environment:'Physical%condi2ons%=%abio*c''Community:'Biological%components%=%bio*c''!'All%interac2ng%organisms%in%an%area%%Ecosystem:'the%whole%system%=%abio*c'&'bio*c%%%'Community' Environment'Bio2c% Abio2c%3/1/15%2%Popula2on%Ecology%Studies%how%and%why%the%size,%range%and%density%of%a%popula2on%changes%over%2me%%'%Key%Features%of%a%Popula2on%Abundance:'The%number%of%individuals%Distribu*on:'Where%they%live%Biomass:'Amount%of%living%material%population3/1/15%3%Popula2on%Distribu2on%Random%Clumped%or%Patchy%Uniform%or%%overdispersal%Factors%Affec2ng%Popula2on%Size%ΔN#=#(B#'#D)#+#(I#'#E)#%Popula2on%size%(N)%Births%(B)%Deaths%(D)%Immigra2on%(I)%%Emigra2on%(E)%3/1/15%4%Exponen2al%Growth%Growth%rate%(r)%does%not%change%over%2me%Logis2c%Growth%in%a%Popula2on%Carrying'Capacity'(K):'Maximum%number%of%individuals%a%habitat%can%support%%As%N%approaches%K…%Increased%intraspecific'compe**on%for%limited%resources%3/1/15%5%Effects%on%Popula2on%Size%Density@Independent''Density@Dependent''• Resource%limita2ons%!%compe22on%• Predators%• Infec2ons%• Temperature%• Flood%or%Drought%Determining%Popula2on%Size%&%Density%Mark%&%Recapture%method%Assump2ons:%%Popula2on%is%randomly%distributed%%Capture%is%random%%Marking%not%fatal%%Marks%not%lost%!%Depends%on%mo2lity%of%organism%3/1/15%6%Determining%Popula2on%Size%&%Density%Transect]quadrat%method%!%Used%for%site]a_ached%organisms%Age%Structure%Data%Stable%Expanding%Declining%Popula2on%pyramids%%3/1/15%7%Age%Structure%Data%Rockfish:%• Older%fish%are%larger%• Larger%fish%produce%more%young%Dangers%at%each%Growth%Stage%%Lime%Swallowtail% Survivorship%Curve%3/1/15%8%Survivorship%Curves%Most%mortality%late%in%life%Mortality%consistent%throughout%life%High%mortality%early%in%life%• Organisms%oden%exhibit%trade@offs'between%reproduc2on%and%other%physiological%func2ons.%%• The%life'history'of%an%organism%is%the%evolved%pa_ern%of%resource%investment%in%each%stage%of%a%given%species’%life2me%Life%History%Fecundity:'reproduc2ve%capacity%3/1/15%9%r@strategists:''• Many%offspring,%low%parental%investment%%• Common%w/%external%fer2liza2on%• Unstable%environments%%K@strategists:'• Few%offspring,%high%parental%investment%%• Common%w/%internal%fer2liza2on%• Stable%environments%Reproduc2ve%Pa_erns%r]%&%K]strategists%Metapopula2on%Group%of%independent%popula2ons%that%are%connected%via%corridors%3/1/15%10%Patches%of%Habitat%In%small,%isolated%patches:%• Decreased%diversity%%• Some%species%ex2nc2on%%When%connected%by%corridors:%• Less%species%ex2nc2ons%Diversity:'The%number%of%different%species%in%an%area%Habitat:'The%place%&%condi2ons%in%which%an%organism%lives%Community 1 Community 2 Community 3 Species A B C D E F Species richness: Species diversity (Shannon index): 1.350 1.794 1.610 5 6 6 Evenness: Low High High Diversity%includes%the%number%of%different%species%(richness)%%&%the%distribu2on%of%individuals%across%species%(evenness)%%3/1/15%11%Island%Diversity%Island%Biogeography%Effect'of'Island'Size'Effect'of'Distance'3/1/15%12%Island%Size%&%Number%of%Species%Species]Area%rela2onship%Species%Interac2ons,%Communi2es%&%Ecosystems%Species%interac2ons%affect%%distribu*on%and%abundance''Intraspecific'interac*ons'='between%members%of%the%same%species%%'Interspecific'interac*ons'='between%members%of%different%species%%3/1/15%13%Interspecific%Species%Interac2ons%• Symbioses:%– Mutualism%(+/+):%obligate%&%faculta2ve%– Commensalism%(+/o)%– Parasi2sm%(+/])%%• Consump2on:%%– Preda2on%&%Herbivory%(+/])%%• Compe22on%(]/])%– Can%also%be%intraspecific%Obligate'Mutualism'=%%%%Both%partners%dependent%on%the%rela2onship.%'Faculta*ve'Mutualism'=%%%%Each%partner%benefits,%but%is%not%dependent%on%the%rela2onship.%%!%Can%be%obligate%for%one%partner%and%faculta2ve%for%the%other.%!%Some2mes%difficult%to%classify%the%rela2onships.%%%Facilita2on% %%%%%%%%% % %%%%%%Obligate%%loosely%coupled % %%(spectrum)% %%%2ghtly%cou pl ed"Range'of'Mutualisms'3/1/15%14%Species%Interac2ons%%%Compe22on:%• Can%be%interspecific%or%intraspecific%• Individuals%or%species%share%a%resource%in%limi2ng%supply%%• Interac2ons%reduce%survivorship,%growth,%and/or%reproduc2on%• Compe22on%is%ALWAYS%density%dependent%Two%types%of%Compe22on%1.%Exploita*ve'Compe**on:'organisms%u2lize%resources%in%%short%supply,%reducing%availability%to%other%organisms%(indirect)%%3/1/15%15%Two%types%of%Compe22on%2.%Interference'Compe**on:%Individual%harms%other%individual%while%seeking%a%resource%(direct)%Interspecific%compe22on%%lab%experiments%2%species%of%paramecium,%Grown%alone%&%together%3/1/15%16%Fundamental%vs.%Realized%Niche %%• Fundamental'niche:'Niche%a%species%could%live%in%•