What makes us all mammals?•mammaryglands,•secondarypalate,•3middleearbones,•brain—neocortex,•bodytemperatureregulatedbybrain(endothermy)

•hair

145

Compiled by Drs John Anderson & Norman Owen-Smith (Wits);

Layout by Ditshego Madopi, Sarah de Villiers, Aneldi van Zyl & Waldo Swart

Like the birds (Part 3), and the flowering plants (Part 2), the mammals (of which we are one) have evolved to prodigious diversity since the 5th extinction

(66 million years ago). That was when the dinosaurs disappeared, leaving a world of empty habitats to be filled. We explore our mammalian diversification & on-going extinction, both of which are tightly linked to climate change!

Cold 20ºCswing Hot

Mio

cene

Olig

ocen

eEo

cene

Pale

ocen

e

Pleistocene

Pliocene

Cre

tace

ous

0

10

20

30

40

50

60

55

65

5

15

25

35

45

80

100

125

Age(Ma) Epoch

Late

Early

Pale

ogen

eN

eoge

ne

PleiPerio

d Climate change

5.3

2.6

Extinction

Jura

ssic

Biodiversity

Diversity of Mammals

Class:1

Orders:28

Families:153

Genera:1,188

Species:5,096

Part 4 Mammals

170

200

Tria

ssic

250

Per-

mia

n

Myr ago0255075100125150175 K-Pg

Eutheria

PrototheriaMetatheria

Theria

255075100125150175

Mesozoic Cenosozoic

Jurassic Cretaceous Paleogene Neogene Q (Q: Quaternary)

Placentalia

Mam

mal

s

GSA2013(Geologicaltimescale);Reisetal2012,ProcRoySoc(timetree);Rippleetal2015,SciAdv(extinction)

Youmightbelievethatyouhave

nothingtodowithextinction,

butsadlyourmodern

lifestyleimpactsheavilyon

theworld.

However,ourlargebrains

canbeusedcreativelytocurb

thisextinctionbymakingmore

informeddecisions.

Carnivora

Perissodactyla

Pholidota

Rodentia

Hereweshowanimalsfromsome50ofthemammalfamilies—groupedintotheirorders&‘superorders’

The mammal timetree

Ice-house5th 6th

4th

3rd

5th

Extinction Extinction

What makes us especially different amongst the mammals is our large brain wired for thought. Yet,in3historicalwavesofextinction,mankindhascausedaseveredeclineinbiodiversity.Today,wehaveboththepowertofurtherdecimatelifeonEarth;ortoprotectit!

P E M PO

Insectivora

Edentata

Perissodactyla

Cetaceae

Primates

Pholidota

Artiodactyla

Carnivora

Rodentia

Lagomorpha

Afrotheria

Marsupialia

Monotremata

Edentata

Chiroptera

Eulipotyphla(Insectivora)

Dermoptera

Artiodactyla

Camelidae

Camelidae

Suidae

Scandentia

Hippopotamidae

Hippopotamidae

Suidae

LateCretaceousTheworld75millionyearsago

Biodiversity& Ex tinction

UniversityPretoria

UniversityWitswatersrand

UniversityStellenbosch

UniversityCapeTown

CranefieldCollege

6th Extinction

red=carnivoresorange=omnivoresgreen=herbivores

Goldenmole

Afrotheria

DugongAardvark

DassieElephantshrew

Tapir

Beaver

Lagomorpha

Pika

Dermoptera

Flyinglemur

Armadillo Monotremata

PlatypusEchidna

Pangolin

Scandentia

Treeshrew

Sloth

Europeanmole

Primates

Bushbaby

Lemur

Otter

Wolf

Cetaceae

Orca

Dolphin

Spermwhale

Chiroptera

Fruitbat

Leaf-nosedbat

MacDonald(ed)2009,Encycl.ofMammals(classification)

Marsupial lion(Australia)

Wooly mammoth(N.America)

Malagasy pygmy hippo(Madagascar)

Wave 1: Over 80% of all large mammals hunted to extinction; except in Africa

What makes us so different?Thoughweareall

geneticallyremarkably

similar,welookextraordinarilydifferent!

We,over5000species,

haveadaptedtoliveinjust

abouteveryenvironment

youcanthinkof!

Here are just three of those species

Plio

-ce

ne

260

225

EoceneOptimum

56 Ma

66 Ma

126 Ma

131 Ma

134 Ma

PETM

mid-Cretaceous radiation of the birds &

flowering plants

Extinction

Extinction

pre 34 MaAntarctica

ca 34 MaAntarctica

AntarcticGlaciation33.9

Ma

AntarcticThawing

23 Ma

AntarcticReglaciation

83.6 Ma

113 Ma

152 Ma

Origin of mammals from mammal-like

reptiles

Extinction6th

3m0.75m0.7m

MarsupialiaWombatBandicoot

NumbatTasmaniandevil

See if you can think of the homes of each of the mammals shown!

Air (flight)Water

(rivers to oceans)

Trees (forest to woodland)

Terrestrial (above & beneath ground)

Cities & villages

Mammal habitats

Wave 2:Out of Mid-East;asfarmersfromc.10,000yearsago

Wave 1:Out of Africa;ashunter-gatherersfromc.50,000yearsago

Wave 3:Out of Europe;asindustrialmanfromc.500yearsago

Extinction caused by:•Populationgrowth;wearenowover7billion•Hunting;forsport&wild-meat•Farming;cultivation,domestication

•Poaching;organisedcrime•Deforestation;&removalofotherhabitat•Climatechange;ourcarbonfootprint

Hot-house

70,000 yrs ago

60,000 yrs ago

45,000 yrs ago30,000 yrs ago 28,000 yrs ago

14,000 yrs ago

Wave 1

Wave 2

Branches of timetreeImagineaveryancienttreeofover200-million-yearsold.Andimaginestillmanymorebranches&twigs(representingfamilies,genera&species)thanareactuallyshownhere.

Mammal evolution & climateAlllivingmammals,inaround150families,evolvedduringa20ºCcoolingperiodfrom50million-yearsago:fromtheHot-houseEarthoftheearlyEocenetotheIce-houseEarthoftoday.

Ifwereversethistrendfarenoughandfastenough,theneverymammalspeciesonEarthfacesextinction!

Big scienceAstheaccuracyofthetimetree(genomics)&theclimatecurveimproves,soourunderstandingoftheinseperabletiebetweenthetwobecomesclearer.

(climate change possibly also played a role)