WHEEEEE 1 What are we Doing Today Whale

WHEEEEE ! 1

What are we Doing Today? • Whale fossil hunt • Whale ankle comparisons • Whale DNA comparisons • WHALE EVOLUTION 2

Becoming Whales 3

Diversity of Whales Today Mysticetes (baleen whales): 4

Diversity of Whales Today Odontocetes (toothed whales): 5

But Where Did They Come From? ONE OF DARWIN’S IDEAS… … I can see no difficulty in a race of bears being rendered, by natural selection, more and more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale. Charles Darwin, The Origin of Species, 1859 (first edition), Chapter 6: Difficulties on Theory Darwin was wrong about the BEAR (he removed this idea in later editions), but spot-on with the process – NATURAL SELECTION. 6

So, Where DID Whales Come From? Here’s a Peek into the Past… 7

Moving in… Notice that the earliest MAMMALS… were TERRESTRIAL - with LEGS ! 8

But WHALES SWIM; they DON’T WALK ON LAND ! So - Where DID Whales Come From? What would the earliest whales look like? 9

The Earliest MODERN WHALES… Only go back to about 23 mya… the beginning of the MIOCENE… Great swimmers… but NO WALKING LEGS ! NOW 5 mya MIOCENE 23 mya 10 65 mya

HOWEVER ! We DO have some whale-like fossils, with strange teeth, NOW 5 mya MIOCENE 23 mya from the EOCENE ! 11 65 mya

NOW But… Where’s the Eocene? NOW Miocene: Earliest modern whales 23 mya 34 mya EOCENE 55 mya 4. 5 bya 65 mya 12

OK! So, where shall we look for Eocene Fossils? Mountains of Pakistan The Tethys Sea 38 55 India Moved North… …Squished into Asia… 13

Where shall we look? Pakistan Lots of exposed marine Eocene rocks in the Pakistan mountains 14

Let’s Hunt Whale Fossils… • • • Work in pairs Open Your Eocene Timeline Remove whale strips from plastic bag Listen for descriptions and timing Place whale strip on timeline Wait for next “discovery” 15

Eocene Epoch Timeline 16

Early Whale Teeth in Dorudon 1936 ~ 36 mya 17

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 18

Early Whale Teeth… in a 4 -legged mammal? a Mesonychid called Pachyaena ~ 55 mya … with tiny hooves! 19

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 20 Pachyaena 55 mya (58 -34 mya) 1955

Early Whale Teeth WITH LEGS ! …and hooves, too! In Pakistan… Pakicetus - an early whale 1983 - Gingerich - Pakistan ~50 mya 21

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 Pakicetus 50 mya (1983 - Pakistan) 22 Pachyaena 55 mya (58 -34 mya) 1955

Early whale teeth in… Basilosaurus ~37 mya and LEGS, too… 1990 Gingerich - Egypt 23

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 Basilosaurus 37 mya (39 -36 mya) 1990 Pakicetus 50 mya (1983 - Pakistan) 24 Pachyaena 55 mya (58 -34 mya) 1955

Early Whale Teeth Rodhocetus - an early whale And tiny hooves, too ! early 1994 - Gingerich - Pakistan ~46 mya 25

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 Basilosaurus 37 mya (39 -36 mya) 1990 Rodhocetus 46 mya (early 1994 - Pakistan) Pakicetus 50 mya (1983 - Pakistan) 26 Pachyaena 55 mya (58 -34 mya) 1955

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 Basilosaurus 37 mya (39 -36 mya) 1990 Rodhocetus 46 mya (early 1994 - Pakistan) Transitional form? Predict What? (draw) Where? Pakicetus 50 mya (1983 - Pakistan) 27 Pachyaena 55 mya (58 -34 mya) 1955

Early Whale Teeth… in Pakistan With tiny hooves, too ! Ambulocetus - the “walking whale” late 1994 Thewissen ~48 mya 28

Eocene Epoch Timeline Dorudon 36 mya (39 -36 my) 1936 Basilosaurus 37 mya (39 -36 mya) 1990 Rodhocetus 46 mya (early 1994 - Pakistan) Ambulocetus 48 mya (late 1994 - Pakistan) Pakicetus 50 mya (1983 - Pakistan) 29 Pachyaena 55 mya (58 -34 mya) 1955

Ambulocetus Carl Buell 30

Whale Phylogeny, 1994 Hans Thewissen 31

But Mesonychids are EXTINCT! SO, Who are the Closest Living Relatives of Whales? Maybe Hooved Mammals? : = Ungulates: Two Orders: • Perissodactyls (odd-toed) • Artiodactyls (even-toed) 32

Perissodactyls Odd-Toed Ungulates Horses & Zebras Rhinos & Tapirs 33

Artiodactyls Even-Toed Ungulates 34

Leg Anatomy… Heel Bone Ankle Bone 35

Ungulate Foot Bones… FOSSIL HORSE FOSSIL PIG Heel Bone Ankle Bone 36

Whale Ankles? Compare ankle bones… Pig Pakicetus two small ridges Prim. Perissodactyl Mesonychid one big ridge Prim. Artiodactyl 37

Whale Phylogeny, 2001 Philip Gingerich 38

But WHICH Artiodactyls? Will DNA Tell Us? Let’s Compare DNA… 39

DNA Analysis Compare segments of beta-casein gene 40

DNA Analysis Compare segments of beta-casein gene 41

DNA Differences 42

DNA Differences 43

DNA Differences Fewer than five differences… • • • 2 3 3 3 3 4 porpoise & sperm whale porpoise & right whale sperm whale & hippo porpoise & hippo right whale & hippo giraffe & deer giraffe & cow & deer 44

DNA Differences Seven differences… • 7 pigs and peccaries DNA Differences Remaining species… Higher numbers - more distantly related 45

Phylogenetic Tree - WHALES Based on DNA Differences 46

Provisional Phylogeny - Cetartiodactyls 47

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Whale Evolution Recap • Fossil teeth link whales to the 4 -legged mesonychids of the Paleo-Eocene • Tiny hooves on mesonychids and early whale toes tie whales to the ungulates • Ankle bones of early whales point to artiodactyl ungulates as the closest relatives of whales 49

Whale Evolution Recap • DNA confirms the artiodactyl connection and points to hippos as the closest cousins of whales • Consilience: these multiple independent lines of evidence strengthen, narrow and confirm the hypothesized close relationship between whales and artiodactyls 50

Whale’s Closest Cousin: Hippos 51

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FAREWHALE! 53

Have a Whale of a Time! 54 FINI