1

Ch13

BIOL100

•  Biodiversity:sumtotalofallorganismsinanarea

•  Splitintothreespecificlevels:

•  Ecosystemdiversity

•  Speciesdiversity

•  GeneBcdiversity

•  Speciesdiversity

•  Numberorvarietyofspeciesinthe

worldorinaparBcularregion

•  Speciesrichness

•  Numberofspecies

•  Evennessorrela4veabundance

•  Extenttowhichnumbersof

individualsofdifferentspecies

areequalorskewed

•  SpeciaBongeneratesnewspeciesandaddstospeciesrichness

•  ExBncBonreducesspeciesrichness

2

•  Taxonomists

•  ScienBstswhoclassifyspecies

•  Commonancestry,abilitytointerbreed

•  Genera

•  Relatedspeciesaregroupedtogether

•  Families

•  Groupsofgenera

•  Everyspecieshasatwo-partscienBficname

•  Binomialnomenclature

•  Genusandspecies

•  Subspecies

•  PopulaBonsofspeciesthatoccurindifferentareasanddifferslightlyfromeachother

•  DivergencestopsshortofseparaBngthespecies

•  OrsBllpotenBallyspeciaBng

•  SubspeciesaredenotedwithathirdpartofthescienBficname

SiberianBger=Panthera)grisaltaica

BengalBger=Panthera)gris)gris

Allsubspeciesof)gershavedisappearedfrom93%oftheirhistoricrange

•  Gene4cdiversityencompassesdifferencesinDNA

•  AmongindividualswithinspeciesandpopulaBons

•  IstherawmaterialforadaptaBontolocalcondiBons

•  PopulaBonswithhighergeneBcdiversity

•  Morelikelytosurvive

•  Cancopewithenvironmentalchange

•  PopulaBonswithlowgeneBcdiversity

•  Morevulnerableto

•  Environmentalchange

•  Disease

•  Inbreedingdepression:geneBcallysimilarparentsmateandproducelessfitoffspring

3

•  Ecosystemdiversity

•  Numberandvarietyofecosystems

•  AlsoencompassesdifferingcommuniBesandhabitats

•  Sizes,shapes,andinterconnectednessofpatcheswithinhabitats,communiBes,orecosystems

•  Speciesnotevenlydistributedamong

taxonomicgroups

•  Manymoreinsects

•  ~80%ofallspecies

•  40%ofallinsectsarebeetles

•  Groupsaccumulatespeciesby:

•  AdapBveradiaBon

•  AllopatricspeciaBon

•  LowratesofexBncBon

•  Speciesrichness

•  Goodgaugeforoverallbiodiversity

•  EsBmatesof5–30millionspecieson

Earth

•  Only1.7–2millionspecies

•  HavebeenidenBfiedanddescribed

•  VerydifficulttoidenBfyspecies

•  Smallorganismsareeasilyoverlooked

•  ManyspecieslookidenBcalunBl

closelyexamined

•  ManyremotespotsonEarthremain

unexplored

4

•  Livingthings

•  DistributedunevenlyacrossEarth

•  La4tudinalgradient

•  Speciesrichnessincreasestowardtheequator

•  Equatorialregions

•  HavehigherplantproducBvity

•  Stableclimates

•  NoglaciaBon

•  Diversehabitatsincreaseniches

•  Increasesspeciesdiversity

•  Ecotone

•  Areaswherehabitatsintermix

•  Havehigherdiversityofniches

•  Thereforehigherspeciesdiversity

•  Ex4nc4on

•  Occurswhenthelastmemberofaspeciesdies

•  Speciesceasestoexist•  Ex4rpa4on

•  DisappearanceofaparBcularpopulaBonlocally

•  NottheenBrespeciesglobally•  CanleadtoexBncBon

•  99%ofallspecieseverexistedarenowexBnct

5

•  Past440millionyears

•  MassexBncBonseliminatedatleast50%ofallspecies

•  DinosaursexBnctatendoftheCretaceousperiod

•  65millionyearsago

•  Madewayformammals

Ex)nc)onsfollowedhumanarrivalonislandsandcon)nents

6

•  TheRedList

•  UpdatedlistofspeciesfacinghighrisksofexBncBons

•  22%ofmammalspecies

•  12%ofbirdspecies

•  16–86%ofallotherspecies

•  Since1970

•  58fishspecies,9birdspecies,and2mammalspecieshavegone

exBnct

•  WestAfricanblackrhinoceros,Baijiwhitedolphin(bothlast

decade)

•  U.S.inthelast500years

•  236animaland17plantspeciesareconfirmedexBnct

•  Actualnumbersareundoubtedlyhigher

http://www.iucnredlist.org/

•  PopulaBonsaredeclining

•  Withshrinkinggeographicranges

•  GeneBc,ecosystem,andspecies

diversityarebeinglost

•  LivingPlanetIndex

•  summarizestrendsinpopulaBons

•  Between1970and2003,theIndexfellby30%

•  Reasonsforbiodiversitylosses

•  MulBfaceted,complex,andhardtodetermine

•  Fourprimarycauses

1.  HabitatalteraBon2.  Invasivespecies3.  PolluBon4.  OverharvesBng

•  Globalclimatechangenowisthefihhcause

7

•  Greatestcauseofbiodiversityloss

•  Farming

•  Grazing

•  Clearingforests

•  Hydroelectricdams

•  UrbanizaBonandsuburbansprawl

•  Afewspecies(i.e.,pigeons,rats)benefitfromchanginghabitats

•  generalists

Lessthan1%ofNorthAmerica’sGreatPlainsremains,andgrasslandbirdpopulaBonshavedeclined82–99%

•  Forests

•  Fragmentedbyroadsandlogging

•  Smallforestfragments

•  Losediversityfastest

•  StarBngwithlargespecies

•  Equilibriumtheoryofislandbiogeography

•  DistribuBonofspeciesonoceanicislands

•  ResultsfromanequilibriumbetweenimmigraBonand

exBrpaBon

•  Predictsanisland’sspeciesrichness

•  Basedontheisland’ssizeanddistancefromthemainland

•  Alsoappliesto“habitatislands”

•  Patchesofonehabitattypeisolatedwithina“sea”ofothers

8

•  Fewerspecies•  Colonizeanislandfarfromthemainland

•  Largeislands•  HavehigherimmigraBonrates

•  Largeislands•  HavelowerexBncBonrates