1. Today – 2/6 Critter in the news Famous USA depositional environments and resulting rocks How to find a dinosaur Phylogenetic trees

2. .5 XC pt quiz – use whole sheet Theropod (meat-eating dinosaur) eggs were laid: a) all at once, firehose-style, like crocs b) one at a time like birds c) two at a time d) different theropods had different styles

3. Archaeopteryx!

13. Administration: Test 2/15 – review sessions next Tuesday and Wednesday, 5-6:30, right here Hmwk 2 postponed NASA Space Grant

14. Last time

15. Portions of the 1947 Zallinger mural at Peabody Museum, 110 ft wide by 16 ft high

16. Two kinds of fossils: Body fossils: preserved body parts such as bones, shells, eggs, skin impressions Trace fossils: preserved marks on the planet left by activity of ancient organisms such as footprints, nests, toothmarks, coprolites, fossil regurgitates. Trace fossils are especially important because they tell us about behavior!

17. How to fossilize a bone: Death followed by burial Permineralization – pore spaces in the bone are filled with minerals precipitated from groundwater Replacement – original material is replaced by other minerals. Rare in bones, common in wood. Complete permineralization and replacement = petrification. 10,000 years minimum fossilization time

18. www.mackenzieltd.com Sedimentary rocks Igneous rocks www.neldamsbakery.com

19. The three rock types Sedimentary rocks – derived from the weathering of pre-existing rocks, or precipitated from aqueous solution Igneous rocks – crystallized from liquid magma or lava Metamorphic rocks – sedimentary rocks that have been physically and/or chemically altered by heat and/or pressure without melting

20. Sedimentary Rocks Record Environment A = Sandstone (beach environment) B = Shale (shallow marine environment) C = Limestone (deeper marine environment) Sedimentary rocks – accumulations of fragments of pre-existing rocks lithify OR minerals precipitate from aqueous solution

21. Mississippi Delta Cape Hatteras, North Carolina

22. Marine transgression – sea level rises

23. Stratigraphic column resulting from a marine transgression Stratigraphic column resulting from a marine regression sandstone silty shale limey shale limestone silty shale limestone sandstone limey shale

24. Sedimentary Rocks Record Environment Sediments come from eroding mountains Sediments sort by weight, so sand deposited at beaches, nearshore: makes sandstone Mud / clay deposited offshore: makes shale (too fine-grained to see individual grains) Calcite precipitated by marine organisms. Deposited in deeper waters where influx of terrestrial material is low: makes limestone

25. Sedimentary Rocks Record Environment Sandstone and shale can also be formed from desert dunes, lake, river and floodplain, and delta deposits Most dinosaurs found in river, especially floodplain deposits Sedimentary rock layers are called strata A distinctive set of strata is called a formation

26. www.wvup.edu/ecrisp/fieldstudiesinutah.html Morrison Formation Sundance Sea

27. rainbow.ldeo.columbia.edu Gondwana Laurasia

28. Morrison Formation Late Jurassic, 154-145 Ma Covers 1.5 million km 2 western NA – outcrops in 13 states and 2 provinces of Ca Seasonally dry, especially in the south. Wetter and swampy (coal beds) in the north All kinds of plants and animals – conifers, ginkos, cycads, horsetails, frogs, fish, salamanders, pteros, mammals, dinos, probably mostly from riparian areas. Perennial water sources even in arid areas. www.colostate.edu

29. www.wyomingtalesandtrails.com/bonewars2.html

30. www.rainbow.ldeo.columbia.edu http://en.wikipedia.org

31. Western Interior Seaway – 80 Ma

37. www.neiu.edu/~awroblew/ Hell Creek Formation

38. Latest Cretaceous, 67-65 Ma Montana, N and S Dakota, Wyoming K-T boundary, “fern spike” Rockies rising to west, huge amounts of sediment being shed into WIS, forming all kinds of great deposits – estuaries, tidal inlets, tidally-influenced fluvial channels, fluvial channels, alluvial plains, lacustrine basins, and coal swamps. Probably all related to a huge delta a la the Mississippi

40. So how do I find a dinosaur? Get a geologic map Colors represent a combination of age and type of rock exposed at surface Look at the legend, find an outcrop on non- marine, Mesozoic sedimentary rocks, go there Score major dinosaurs!

42. Clades: how we think about relatedness in this class Derived character: a feature of an organism that has changed from the ancestral condition. “Evolutionary novelties” Primitive character: a feature of an organism that has not changed from the ancestral condition Clade: a group of organisms that share derived characters A clade is a group of organisms that are more closely related to each other than they are to any other organisms

45. Dinosaur “A reptile-like or bird-like animal with an upright posture that spent its life on land” Evolutionary novelties (shared derived characters): advanced mesotarsal ankle, femur with ball, pelvis with hole for femur ball. Allowed upright posture with legs under the body, not sprawled to side. This allowed high levels of activity! Three of more pelvic (sacral) vertebrae

46. Phylogenetic tree = family tree Older Younger -----------Time---------→

47. A lineage of fish developed feet, became the first tetrapods (basically amphibians) A lineage of tetrapods developed eggs with membranes that could survive on land, became amniotes

48. Eye socket anapsids – no holes behind the eye socket synapsids – one hole behind the eye socket diapsids – two holes behind the eye socket