Rules to a story! … but today, not in that order:! •!What?! When? Dating methods and deep time! •!When?! Where? How do fossils form - ANTH 42: Primates in Nature! taphonomy! •!Where?! What? The primate fossil record! Lecture 2:! •!Why?! Why? Evolution and its Primate evolution! mechanisms (including natural selection) [later lecture!]! http://weber.ucsd.edu/~jmoore/courses/anth42web/! WHEN: Dating Bishop James Ussher: 1650 WHEN: Dating methods! Uniformitarianism methods! calculated from Bible that & the earth! Creation occurred 4004 BC! Strata laid down in layers, oldest are deepest.! Mary Ann Mantell: 1820 discovered “Iguanodon” tooth (Sussex, UK)*! Younger or older?! Richard Owen: 1842 coined Sometimes, word “Dinosaur”! geological 1854: Dinner in the Iguanodon! processes can Was hard to reconcile 6,000 years with creatures SO muddle that up.! different and so clearly extinct.! Uniformitarianism violated.! * Other giant bones known, but this specimen first to kick off ‘modern’ interest! But with more data, can usually figure it out.! WHEN: Dating methods! WHEN: Dating methods! 1566! " 100 years trying to date fossils. Absolute. ! Recognized fossil ‘stages’ - rocks with Dendrochronology! no crinoids or coral overlaid by rocks (tree rings)! Growth depends on with crinoids and coral, but no rainfall; annual rings.! dinosaurs, so could talk about “age of Count inward from crinoids” and “age of dinosaurs”. outermost ring, get age of tree.! Knew the order taxa showed up Bristlecone pine 5,000 yrs! (relative dating), but argue about when in years (absolute dating).! Buried log! WHEN: Dating methods! 1566! WHEN: Dating methods! Absolute. Dendrochronology! Absolute. ! River oaks, S. Radiometric! Dendrochronology! Germany: > (tree rings)! 10,000 yrs! Isotopic decay - Growth depends on measurable rainfall; annual rings.! Bristlecone rates! Pines, SW Count inward from USA: 8,500! outermost ring, get age of tree.! Bristlecone pine 5,000 yrs! Buried log! Buried log! WHEN: Dating methods! • total amount of WHEN: Dating methods! Absolute. Dendrochronology! carbon! Absolute. Dendrochronology! Radiometric! • amount of 14C! Radiometric! Isotopic decay - Isotopic decay - 14 12 • C/ C at death Uranium - Lead (U/Pb)! measurable measurable (atmospheric)! rates! 235U -> 207Pb: 700my! rates! 238 206 ! 14 U -> Pb: 4,500my! N! ! 14C! Potassium - Argon (K/Ar)! 40 40 K -> Ar: 1,300my! PRODUCT Y Unstable isotope Radioactive decay of DECA Radioactive decay of unstable isotopes - half-life! T ! T ! T ! T ! T ! unstable isotopes - half-life! Death! 5,730! 11,460! 17,190! 22,920! 28,650! T0! 1 2 3 4 5 TIME! TIME! WHEN: Dating methods! Absolute. Dendrochronology! Radiometric! NOW:! 4.4 billion years ago! 500 million years ago “DEEP TIME”! (mya)! Uranium - Lead (U/Pb)! ! 235U -> 207Pb: 700my! Y 238U -> 206Pb: 4,500my! ! Potassium - Argon (K/Ar)! DECA PRODUCT 40 40 K -> Ar: 1,300my! Unstable isotope Radioactive decay of unstable isotopes - half-life! T0! T1! T T T T 2! 3! 4! 5! 500 million 500 million years ago years ago (mya)! (mya)! 500 million 500 million years ago years ago (mya)! (mya)! And now to shift scales... ! 500 million years ago (mya)! And now to shift scales... [fish, after all...]! 500 million years ago (mya)! 65mya! WHERE: Taphonomy! “Deep time”! WHERE: Taphonomy! Taphonomy: the study of burial and decay; creation of fossils.! Chewed up, pulled apart! ! Trampled, dispersed! TION Weathered! Gain of information (?): 65mya! Chimp- Plant roots! human LCA What happened " 6mya! INFORMA Buried! to this horse?! Geological deformation! “Deep time”! LOSS OF Exposed (partially?)! WHERE: Taphonomy - one consequence! WHERE: Taphonomy - one consequence! Living species Same color = Living species Same color = closely related.! closely related.! •! Because VAST MAJORITY of individual organisms that have ever lived do NOT ! become fossils (let alone recognizable ones), ! ! TION •! And of the ones that do, only a TINY TION MINORITY then become exposed and available for study,! Count species in modern habitat, •! We expect gaps in the fossil record….! INFORMA INFORMA compare with fossil species in similar “fossil habitat”, Fossils! LOSS OF LOSS OF estimate # missing species. Guess?! " 90%! (Uniformitariansim)! WHERE: Taphonomy - one consequence! WHERE: Taphonomy - one consequence! ! ! TION TION •! Cheating to connect branches with species we haven’t found, even if •! Cheating to connect branches with species we we know they must have existed. ! INFORMA haven’t found, even if know they must have existed. ! INFORMA •! So connect up available species.! •! So connect up available species.! •! Make mistakes.!•! Find new fossil, revise understanding (and get closer to reality)! LOSS OF •! Make mistakes.! LOSS OF WHERE: Taphonomy - another consequence! WHERE: Taphonomy - another consequence! Jaws and “Lucy”! Aegyptopithecus especially (jaw and skull teeth are found ! HARD! ! separately)! TION TION Dinosaur National Monument INFORMA What PARTS get left?! INFORMA (UT)! Faces aren’t easy to chew and don’t have much meat (medium-size animals).! How do we put them together?? ! LOSS OF LOSS OF WHAT: The record.! Origin of mammals,Origin & recognition ofprimates mammals! ! •! What does a mammal look like Synapsids! when it’s a bone?! ~1m! Mammae don’t Bony definition of fossilize! mammal! Reptile --> mammal! •! What’s the difference between Primates! Jurassic! a primate and a possum?! Fish! Reptiles! Dinosaurs! 500 million years - 1st fish to present! Primates v. other mammals! Primates v. other Maybe primate (tree shrew)! Postorbital bar --> bony orbit! mammals! “Postorbital bar is usually complete”! But it’s not real obvious, hence disagree over Tupaia! Postorbital bar! Not primate (elephant shrew)! Primate phylogeny (Falk)! Plesiadapiforms (‘proto-primates’)! Adapiforms (prosimians)! Omomyiforms (tarsiers [?])! Late Oligocene (early simians)! Early Miocene (apes)! Prosimian vs. anthropoid skulls! Madagascar (lemur megafauna)! 80 - 90mya! 130 mya, Conceivable 120 mya Early Cretaceous ! South 85mya Late Cretaceous! ancestors of America, primates Africa, around, but India all continents connected! separate.! Dinosaurs still No dominant.! “primates”! Madagascar off on own.! 115 mya, End Cretaceous drifting - K/T boundary apart.! 65 mya - ‘primates’!! Plesiadapiforms! Plesiadapiforms! Weird jaw + Eyes lateral! Purgatorius! grasping ~ rat size; ~ 65mya paws…! Purgatory, Montana. “primatomorph”! Nail, not claw! Prosimians - or “flying lemurs”? ! Plesiadapis: ~2 ´ (beaver-sized); North Dakota! O! Definitely primate O! A! O! A! A! Eocene! 45mya Eocene Adapids, Omomyids! …! Adapids! Adapiforms! A! Omomyids! Adapis (France)! Notharctus! Wyoming ~ 40-50mya! Adapis! Shoshonius! Omomyids! Lots of specimens and # species! Note forward facing eyes, postorbital bar!.