EOSC116 Assignment: Some dinosaur fossils from western North America

Transcription

1 EOSC116 Assignment: Some dinosaur fossils from western North America Learning goals 1. Interpret some details about given dinosaur and other fossils. 2. Extend the work done in the previous assignment by considering opportunities and limitations for relating dinosaur populations associated with these specimens with each other. Introduction and purpose The previous assignment introduced you to many real and possible fossils and fossil locations related to western North America in the Late Cretaceous. In this assignment you will work with some of the specific fossil specimens in more detail, interpreting some quantitative characteristics of the organisms, and thinking about the extent to which ages and locations enable (or limit) useful (or not!) comparison between dinosaur populations. Instructions 1. Review the resources you are given about the 5 specimens or specimen locations. While reading, use the following table to gather information needed to answer questions. The table will not be tested but you will need the information while working on questions. 2. Complete a paper copy of this worksheet, answering all questions posed. Maps, fossils and other information are provided in the separate collection of resources. 3. When you are finished this worksheet, proceed to the associated quiz on Connect. This is not a test because you will copy results from your paper worksheet into similar automatically graded questions. This procedure automates the delivery and grading of your work in this fully online course. 4. DO NOT work on the Connect quiz before finishing the paper version. You will run out of time. Location number and place name Specimen (fossil types, organism names) Dates &/or age names

2 Begin here 1. After learning about our five specimens, find location numbers on the map where fossils were found and identify locations in spaces provided in the following table (no zeros, no spaces, just the one or two digit number). Specimen descriptions The Lambeosaurus displayed at the PME. Recently found Theropod thigh bone fossil. Late Cretaceous Carnosaur, Hadrosaurs and Ornithomimus tracks. Early Cretaceous turtle & foot print fossils found by P. Mustard. Late Cretaceous ankylosaur trackways that sparked the discovery of many types of dinosaur and other fossils. Map location 2. Now we will put these fossils into the context of geological time. Your resources include the Jurassic and Cretaceous portion of the Geological time scale published by the Geological Society of America. From which named Age (NOT epoch) do our six fossils come from? Specimen descriptions The Lambeosaurus displayed at the PME. Recently found Theropod thigh bone fossil. Carnosaur, Hadrosaurs and Ornithomimus tracks at Ross River. Youngest turtle & foot print fossils found by P. Mustard. Oldest fossils at Tumbler Ridge. Youngest fossils at Tumbler Ridge. Named age 3. What evidence helped determine the age of the theropod thigh bone recently found in the Gulf Islands of Washington State? a) Dating by association of this fossil with the sediments in which it was buried. b) Radiometric dating of bone material c) Ash layer containing dateable minerals. d) Radiometric dating of surrounding or nearby rock material e) Distinctive characteristics of the bone indicate a type of theropod of well constrained age. 4. What is one reason that this was such an unusual specimen? a) Fossils of such theropods are globally rare. b) Fossilization of this type of specimen is uncommonly difficult c) This area was isolated during the existence of dinosaurs d) It is a land based animal found fossilized in marine rocks e) The region was mostly desert at that time. f) The western edge of North America was too tectonically active to be a suitable dinosaur habitat. 5. Was this fossil part of the thigh of a monster theropod like Daspletosaurus, or a small one like Avimimus Portentosus? (You are not required to know these terms, but it is interesting to look them up.) How can paleontologists estimate the approximate size of this dinosaur with only a fragment of a thigh bone? The answer is by comparing to other theropod fossils that are more complete. Resources contain all the information you need to make your own estimate of the length of the whole thigh bone. What measurement for x do you obtain using the scale (ruler) provided? Enter the number in units of millimetres. You must be correct to within plus or minus 30mm. BE CAREFUL OF UNITS. [ ]

3 6. Now use your value of x and the graph provided to estimate the thigh bone length in units of mm. What estimated length do you obtain? You must be correct to within plus or minus 60mm. [ ] 7. Having read resources about all 5 specimens (Pacific coast theropod, UBC s Lambeosaur, Ross River, Tumbler Ridge, N. of Terrace), at which 3 location was evidence found of Hadrosaurs of any age? 8. In the previous question you identified where evidence of Hadrosaurs was found. However these finds were not all the same age. Which two or more of these age ranges are represented by all these Hadrosaur finds? (You don t have to attach ages to places just identify those ages that are represented by the Hadrosaur finds encountered in this exercise.) a. 120 ± 5Ma b. 90 ±5Ma c. 83 ±5 Ma d. 74 ±5 Ma 9. At which 3 locations did resources you were given indicate that evidence of Theropods or Carnosaurs had been found? 10. In the previous question you identified where evidence of Theropod or Carnosaur fossils was found. However these finds were not all the same age. Which two or more of these age ranges are represented by all these finds? a. 120 ± 5Ma b. 90 ±5Ma c. 83 ±5 Ma d. 74 ±5 Ma 11. At which 3 of the five locations did our resources identify evidence that may be suitable for comparing similarities of dinosaur populations at 83 ±5 Ma? 12. At which of five locations did our resources identify evidence that may be suitable for comparing similarities of dinosaur populations at 73 ±5Ma?

4 13. At which one of these five locations did our resources identify evidence only for dinosaur populations much older than 84Ma? 14. One more fossil worth studying briefly is the PME s fantastic ammonite specimen. The specimen s label on its black base tells us where it was found. Look up this location and identify which of our 13 dot locations this is likely to be closest to. Enter just the dot s number with no words or spaces. [ ]. 15. In this course s previous assignment we claimed that a specimen of type St #3 (a land based organism) was found near the ammonite s location in association with a 65Ma age marker, and another specimen of type St #5 (shallow or coastal waters) was found there in association with an 85Ma age marker. Therefore, which environment was associated with the time closest to the age attributed to the Ammonite? a) Land b) Shallow or coastal c) Deep d) Neither 16. Is this environment consistent with the environment you expect ammonites to have lived in? a) Yes b) No c) Cannot be determined d) I don t know how to answer this. 17. Given that these two different fossils were found in relatively close proximity, which one or more of these explanations might help explain how both of these fossils could be found in this region of Alberta? a) The shape of the shallow sea s coastline could have been variable enough to explain this result even if both fossils were found near this location. b) The time between 65 Ma and the ammonite s age was sufficient for the sea level (i.e. the coast line s position) to have risen and lowered enough so that both fossils could have been found near each other. c) Both fossils could have lived in the same environment. d) One of the fossils could have been transported from elsewhere. e) Either one of these organisms could have moved itself from its normal living environment into the environment normally occupied by the other. f) None of these ideas are reasonable. 18. Let s wrap up this exercise with a summary paragraph. Select correct words for each from these options: increased, decreased, more, less, north, south, east, west. In a previous exercise we learned that before 85 Ma, the ocean plate off the [ ] coast of North America was moving [ ] ward so that elevations in the Rocky Mountains [ ] and elevations in the foreland basin ([ ] of the Rockies) [ ]. Between 85 and 65 Ma ocean plate motion shifted to moving [ ] ward and the inland sea s sea level steadily [ ]. As a result of these tectonic processes, dinosaurs associated with fossils recently found near Vancouver (i.e. [ ] of the Rockies) were [ ] likely to be genetically similar to dinosaurs in Asia and probably [ ] like those living near the inland sea. However, relating geographically separate fossils must be done cautiously. For example, fossils at Terrace are [ ] of the Rockies but are

5 [ ] ancient than all other fossils we encountered. In comparison, fossils at Tumbler ridge are much [ ] varied in age and [ ] varied in terms of organism types. Meanwhile, fossils from different living environments that were found a few kilometers apart in [ ] [ ] ern Alberta, but with a difference in age of 3 5 million years, suggest that the inland sea coast was probably [ ] complicated and [ ] variable over time than might be assumed when finding only single fossils at any one location. That s it for the worksheet. Now proceed to the Connect quiz for data entry. If you have done all work on this worksheet, the Connect quiz should take only 15 minutes or so. It s just a matter of copying answers from this worksheet into multiple choice, matching, fill blank, and drop down choice questions.