Dinosaur Traces. Dinosaurs first roamed Earth 200 million years ago during the Jurassic period.

Transcription

1 Dinosaur Traces Dinosaurs first roamed Earth 200 million years ago during the Jurassic period. Sometime during the late Cretaceous period (approximately 70 million years ago) the dinosaurs died off. Today, we only know of their existence from the fossil remains. A fossil is a term used to geologists to describe any direct evidence of an organism more than 10,000 years old. This could be part of the original organism such as a bone or imprints such as footprints that are preserved in frozen soil or asphalt lakes. Paleontology is the study of the fossils of animal and plant life. Paleontologists are scientists who study these fossils. One type of paleontologist studies the fossil remains of dinosaurs to determine what types of dinosaurs might have existed, what they ate, and how they lived. This is a large puzzle they are solving using not much more than bones! When a dinosaur fossil is found, a professional paleontologist will carefully and systematically excavate the area for more bones and chart the position of each bone found. They will use their knowledge of geology and dinosaur anatomy to determine where the rest of the bones may be buried. The bones of a single dinosaur skeleton generally lie at the same level of rock. If more of the skeleton is found, heavy equipment may be necessary to remove the top layers of soil, rock, and dirt. However, when the scientists are in the vicinity of the dinosaur skeleton, only small hand tools are used to prevent damage to the skeleton. It is very tiring, painstaking work. Each bone that is uncovered is carefully charted and its location is recorded on a map. All this information will help solve the mystery of the dinosaur s life and death. SDSC Science Enrichment Program 1

2 Once the bones are uncovered, they are carefully encased in plaster for transport back to a laboratory. There the plaster as well as any remaining rock is removed from the bone. It may take days to do a single bone. (Think of how many bones are in a skeleton!). Finally it is the paleontologists job to identify the dinosaur and perhaps to fit the bones back together. In this lab you get to be a paleontologist. Instead of real fossil bones you will take rubbings of plaster casts of bones. After the rubbings are taken, the challenge is to reconstruct the complete skeleton and identify the dinosaur to which it belonged. SDSC Science Enrichment Program 2

3 Part A: Crayon Rubbings The first part of the lab is taking the actual rubbings. There are 3 different dinosaurs included in the kit: Veloceraptor, Triceratops, and Tyrannosaurus rex. You teacher may tell you what type of dinosaur you will be working on or she may have you figure that out from the rubbings. Each of the dinosaurs has six plaster casts that you will need to take rubbings. Some of the casts may have one bone and some may have 6 or more. Just make sure you take a rubbing of each bone on each of the 6 casts. Work on only one dinosaur at a time. If you completely finish the lab for one you may go back and do a second. To make a rubbing gather the following supplies: 1. Dinosaur fossil kit (share with 4-5 others) 2. Black or red lumber crayon 3. 1 sheet newsprint Taking the Rubbing: 1. Gather with your group of 3or 4 at the same table. 2. Each member of the group should take 1 or 2 plaster casts to start with. 3. Place a piece of paper over the casts and firmly and evenly rub over it with the crayon. (Your teacher will demonstrate this.) The outline of the bones should appear. Remember to do all the bones on the cast. 4. Repeat the rubbings for your second plaster cast. 5. When everyone in the group has done their casts, exchange casts. 6. Continue to take rubbings until you have done all six casts SDSC Science Enrichment Program 3

4 Part B: Constructing and Identifying the Dinosaur To construct your dinosaur gather the following supplies: 1. 2 pieces construction paper 2. Scotch tape 3. Glue stick 4. Laminated dinosaur fact sheet 5. Laminated Time Line Procedure: 1. Tape 2 pieces of construction paper pieces together by overlapping them in back approximately 1 inch and taping 2. Assemble your cut out skeleton pieces so that they a complete skeleton. If you have trouble with this your teacher can give you a hint. 3. Once your skeleton is correct, glue it onto the construction paper. 4. Identify what dinosaur you constructed. 5. Label your picture with the name of your dinosaur and your name. 6. If time permits, repeat for another type of dinosaur SDSC Science Enrichment Program 4

5 Discussion: A. General questions. 1. What kind of dinosaur have you uncovered? How can you tell? 2. How long do you think it has been here? (Hint: look on your timeline) 3. In what time period(s) did it exist? 4. Why do you think it ended up here? SDSC Science Enrichment Program 5

6 B. Specific questions. 1. How many different parts of the dinosaur can you label? What are they? 2. How many claws can you see? 3. How many teeth can you count? 4. How many ribs can you count? 5. How many legs did this dinosaur have? 6. Do you think this dinosaur was fast or slow? How can you tell? 7. Can you tell what the diet of this dinosaur might have been from the information provided? SDSC Science Enrichment Program 6

7 8. Was this dinosaur an herbivore (plant eater), carnivore (meat eater), or omnivore (both)? 9. If dinosaurs and people were living at the same time, do you think this dinosaur would have been friendly to people? Explain. 10. Name 5 other animals that were living at the time of dinosaurs Name 5 plants that were living at the time of dinosaurs SDSC Science Enrichment Program 7