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1 WHEEEEE ! 2 What are we Doing Today? Whale fossil hunt Whale ankle comparisons Whale DNA comparisons WHALE EVOLUTION.

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Presentation on theme: "1 WHEEEEE ! 2 What are we Doing Today? Whale fossil hunt Whale ankle comparisons Whale DNA comparisons WHALE EVOLUTION."— Presentation transcript:

1

2 1 WHEEEEE !

3 2 What are we Doing Today? Whale fossil hunt Whale ankle comparisons Whale DNA comparisons WHALE EVOLUTION

4 3 Becoming Whales

5 4 Diversity of Whales Today Mysticetes (baleen whales):

6 5 Diversity of Whales Today Odontocetes (toothed whales):

7 6 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.

8 7 Here’s a Peek into the Past… So, Where DID Whales Come From?

9 8 Moving in… Notice that the earliest MAMMALS… were TERRESTRIAL - with LEGS !

10 9 But WHALES SWIM; they DON’T WALK ON LAND ! So - Where DID Whales Come From? What would the earliest whales look like?

11 10 The Earliest MODERN WHALES… 65mya NOW MIOCENE 23 mya Only go back to about 23 mya… the beginning of the MIOCENE… Great swimmers… but NO WALKING LEGS ! 5 mya

12 11 HOWEVER ! 65mya NOW MIOCEN E 23 mya We DO have some whale-like fossils, with strange teeth, from the EOCENE ! 5 mya

13 12 But… Where’s the Eocene? NOW 4.5bya 65mya NOW 55 mya 34 mya EOCENE Miocene: Earliest modern whales 23 mya

14 13 OK! So, where shall we look for Eocene Fossils? The Tethys Sea India Moved North… …Squished into Asia… Mountains of Pakistan 55 38

15 14 Where shall we look? Pakistan Lots of exposed marine Eocene rocks in the Pakistan mountains

16 15 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”

17 16 Eocene Epoch Timeline

18 17 Early Whale Teeth ~ 36 mya 1936 in Dorudon

19 18 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936

20 19 Early Whale Teeth… in a 4-legged mammal? a Mesonychid - called Pachyaena ~ 55 mya … with tiny hooves!

21 20 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936 Pachyaena 55 mya (58-34 mya) 1955

22 21 Early Whale Teeth Pakicetus - an early whale ~50 mya Gingerich - Pakistan WITH LEGS ! In Pakistan… …and hooves, too!

23 22 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936 Pachyaena 55 mya (58-34 mya) 1955 Pakicetus 50 mya ( Pakistan)

24 23 Early whale teeth in… Basilosaurus ~37mya and LEGS, too… 1990 Gingerich - Egypt

25 24 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936 Pachyaena 55 mya (58-34 mya) 1955 Pakicetus 50 mya ( Pakistan) Basilosaurus 37 mya (39-36 mya) 1990

26 25 Early Whale Teeth Rodhocetus - an early whale ~46 mya early Gingerich - Pakistan And tiny hooves, too !

27 26 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936 Pachyaena 55 mya (58-34 mya) 1955 Pakicetus 50 mya ( Pakistan) Basilosaurus 37 mya (39-36 mya) 1990 Rodhocetus 46 mya (early Pakistan)

28 27 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936 Pachyaena 55 mya (58-34 mya) 1955 Pakicetus 50 mya ( Pakistan) Basilosaurus 37 mya (39-36 mya) 1990 Rodhocetus 46 mya (early Pakistan) Transitional form? Predict What? (draw) Where?

29 28 Early Whale Teeth… in Pakistan Ambulocetus - the “walking whale” ~48 mya late 1994 Thewissen With tiny hooves, too !

30 29 Eocene Epoch Timeline Dorudon 36 mya (39-36 my) 1936 Pachyaena 55 mya (58-34 mya) 1955 Pakicetus 50 mya ( Pakistan) Basilosaurus 37 mya (39-36 mya) 1990 Rodhocetus 46 mya (early Pakistan) Ambulocetus 48 mya (late Pakistan)

31 30 Ambulocetus Carl Buell

32 31 Whale Phylogeny, 1994 Hans Thewissen

33 32 But Mesonychids are EXTINCT! Perissodactyls (odd-toed) Artiodactyls (even-toed) Maybe Hooved Mammals?: = Ungulates: Two Orders: SO, Who are the Closest Living Relatives of Whales?

34 33 Perissodactyls Odd-Toed Ungulates Horses & Zebras Rhinos & Tapirs

35 34 Artiodactyls Even-Toed Ungulates

36 35 Leg Anatomy… Heel Bone Ankle Bone

37 36 Ungulate Foot Bones… FOSSIL HORSE Heel Bone Ankle Bone FOSSIL PIG

38 37 Whale Ankles? Mesonychid Prim.Perissodactyl Prim. Artiodactyl Pakicetus Pig Compare ankle bones… one big ridge two small ridges

39 38 Whale Phylogeny, 2001 Philip Gingerich

40 39 But WHICH Artiodactyls? Will DNA Tell Us? Let’s Compare DNA…

41 40 DNA Analysis Compare segments of beta - casein gene

42 41 DNA Analysis Compare segments of beta - casein gene

43 42 DNA Differences

44 43 DNA Differences

45 44 DNA Differences Fewer than five differences… 2 porpoise & sperm whale 3 porpoise & right whale 3 sperm whale & right whale 3 sperm whale & hippo 3 porpoise & hippo 3 right whale & hippo 3 giraffe & deer 3 giraffe & cow 4 cow & deer

46 45 DNA Differences Seven differences… 7 pigs and peccaries DNA Differences Remaining species… Higher numbers - more distantly related

47 46 Phylogenetic Tree - WHALES Based on DNA Differences

48 47 Provisional Phylogeny - Cetartiodactyls

49 48

50 49 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

51 50 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

52 51 Whale’s Closest Cousin: Hippos

53 52

54 53 FAREWHALE!

55 54 Have a Whale of a Time! FINI


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