FoSSil Puzzler (1 Hour)

Transcription

1 FoSSil Puzzler (1 Hour) Addresses NGSS Level of Difficulty: 2 Grade Range: 3-5 OVERVIEW Students will examine and sketch various trace fossils from an unknown creature and then construct an image of the creature that they believe produced these fossils. Topic: Fossils Real World Science Topics: An exploration of how trace fossils are used by scientists An exploration of how scientists draw inferences from pieces of data Objective Students will gain an understanding of how scientists use trace fossils to construct a model of an unknown creature and infer information about the creature. Materials Needed for Each Team of 2-4 Students: modeling clay one oddly shaped doll (such as a fictional animal or alien) Materials Needed for Student Activity (each group of two to four students): set of three clay fossil imprints pencils or pens large paper 1

2 FoSSil Puzzler Teacher Preparation Obtain a doll with a unique body structure, such as a fictional animal or alien. Break off small mounds of modeling clay so that each group of two to four students will have imprints from three mounds. Press various parts of the doll into the mounds to create fossil imprints. Each imprint should be different. Be sure to imprint the same part of the body from various angles (for example, imprint the side of the head, the front of the head, the top of the head, and so on). However, try not to imprint a feature that gives away too much information; it is important that students cannot guess what the creature is. If time permits, you may make a second set of fossil imprints using a different doll. NGSS Three-Dimensions Science and Engineering Practices Disciplinary Core Ideas Crosscutting Concepts Analyzing and Interpreting Data Analyzing data in 3 5 builds on K 2 experiences and progresses to introducing quantitative approaches to collecting data and conducting multiple trials of qualitative observations. When possible and feasible, digital tools should be used. LS4.A: Evidence of Common Ancestry and Diversity Fossils provide evidence about the types of organisms that lived long ago and also about the nature of their environments. Scale, Proportion, and Quantity Observable phenomena exist from very short to very long time periods. 2

3 Steps for Fossil Puzzler 1. Warm-up Activity: Introduce the concept of fossils by showing images of fossilized shells, bones, tracks,etc. Photos of fossils can be found online, and most libraries will have books about fossils. Students will probably be familiar with dinosaur fossils, but provide examples of other types of fossils such as shells and footprints. Explain to students the difference between body fossils and trace fossils. Body fossils contain the preserved remains of the original organism such as bones, teeth, wood, and shells. Trace fossils include all preserved items that were not part of the organism s body, such as imprinted tracks, eggshells, feces, burrows and so on. Use dinosaurs as an example to illustrate the point. A dinosaur body fossil is a bone that belonged to the skeleton of the dinosaur, and a dinosaur trace fossil is a footprint that was made while the dinosaur was walking in mud. Remind students that most dinosaur skeletons that we see in museums today are made up only partly of actual fossil bones. The rest of the skeleton is made of model bones. Have a discussion about how scientists make observations and measurements of dinosaur footprints (trace fossils) to construct the models of dinosaur feet we see in museums. Talk about how they might do this; in other words, what information can be learned by examining the imprints? Students should identify features such as shape, size, and possibly texture. 2. Separate students into groups of two to four students. Distribute sets of three clay fossil imprints. Distribute pencils and Student Handouts. 3. Ask students to examine the clay and determine which types of fossils these are. They should realize that these are trace fossils because they are imprints of a creature. Have students examine the size, shape, and texture of the fossils. 4. Have students draw each fossil on their Student Handouts. Encourage groups to discuss what type of body part they think each fossil represents. Have students discuss and draw what type of animal the fossils might compose. 5. After each group has examined and made drawings of their set of fossils, have them swap sets with another group. Tell them to repeat the process of observation, drawing, and discussion with the new set. Have students draw a revised version of the creature based on these new fossils. 6. Ask students to discuss how fossils from different sets might offer different or additional clues. Do the new fossils represent new parts of the creature s body or the same parts that they have seen only imprinted from a different angle? How does this new information change their vision of the mystery creature? 7. Have students continue to swap fossils until each group has sketched all fossils. Then have groups decide on a final version of the creature that they think created the fossils. Groups should sketch a front, back, and side view of the creature on a large piece of paper. Have students hang up these drawings on the board when they are finished. 8. If time permits, the students may repeat this process with a different set of fossil imprints (from another 3

4 Steps for Fossil Puzzler doll or object). 9. Wrap-up Activity: Lead a class discussion about the similarities and differences between each group s final sketches of the creature. Ask students how they decided which part of the creature s body each fossil represented, and how they ultimately decided what creature the fossils composed. What assumptions did they make? For example, maybe the fossil showed rounded toes with claws so students decided the fossil was a paw print. If they thought the fossil was a paw, how did this help them identify the larger animal? Did they assume it was an animal with fur, such as a dog or a cat? Show the class the actual creature that imprinted the fossils. Discuss and compare the student drawings with the creature. Discuss whether students were correct in identifying the fossil imprints with the corresponding part of the creature. Did the students make any assumptions about the creature based on particular fossils? If so, were any of these assumptions incorrect? What additional information would have been helpful in identifying the fossils? Were there any parts of the animal s body that were not imprinted in the fossils? Explain that scientists have to make assumptions about the structure of ancient animals based on the limited body fossils and trace fossils that they find. When they find new fossils, they must revise their initial idea of how the creature might have looked. Explain that science is a process of gathering evidence, drawing conclusions, and revising these theories when new evidence emerges. Have students answer the questions on the Student Handout. Fossil Puzzler Extension Activity To understand the concept of how trace fossils are formed better, have students make their own fossils. Distribute modeling clay to each group and instruct them to make their own imprints. Have students make imprints of their own body parts, such as fingers or teeth (at the teacher s discretion, and only if clay is non-toxic), or they can make imprints of small objects such as coins. They can also use toothpicks or paper clips to press and draw in the clay. Tell students to make distinct impressions because other students in the class are going to have to guess what object left the fossil imprint. Once students have completed their imprint, have them swap trace fossils with each other. Have students examine and sketch the mystery fossil. Ask students to determine the object that left this imprint. Have them explain their reasoning with their group members. Then, have students return the trace fossils to the original imprinter and have students reveal the identity of the objects. 4

5 Fossil Puzzler BACKGROUND INFORMATION What is a fossil? A fossil is the remains or imprint of an organism that lived a long time ago. Fossils are made of the hard parts of plants and animals such as teeth, bones, shells, and wood. Fossils may also be made by the movements or impressions of plants and animals. These types of fossils, such as footprints and leaf molds, are called trace fossils. Trace fossils do not contain the remains of the organism that made them, only the imprints. How do fossils form? Fossils may form in several ways, but the most common form of preservation is permineralization. In this process, a dead organism (or the trace of one) is buried in sediment. This protects the dead organism from rotting or being eaten by scavengers. Beneath the sediment, the soft parts of the organism (such as flesh and hair) decay, leaving only the skeleton or shell behind. As the organism is buried deeper and deeper, minerals in the sediment fill into the pores of bones, teeth, shell, or wood. After millions of years, the buried sediment turns into solid rock that encases the fossil. Where are fossils found? Fossils are usually found in sedimentary rocks. Fossils may also be found in streams or beaches where they have been washed out of rocks. Sometimes, fossils may be preserved by volcanic ash or amber. How common are fossils? Although millions of fossils have been discovered, they are rare compared to the billions of plants and animals that have lived on Earth throughout time. Most plants and animal bodies are destroyed when they die, often by being eaten by another animal, decomposition, or being broken down through transportation. To form a fossil, the death, burial, and preservation of an organism must all come together under very precise conditions. It is highly unusual for all those conditions to occur simultaneously. Therefore, the chances of a dead organism turning into a fossil are quite rare. How old are fossils? All fossils are very old, although some may be much older than others. To be called a fossil, an object must be at least 10,000 years old. However, some fossils are millions and even billions of years old! The fossil record shows that the oldest animal fossils are more than 550 million years old, while the oldest fossil bacteria may be almost 3 billion years old. Key Vocabulary organism: any living thing, such as a plant, animal, or bacterium trace fossils: the non-body remains of an organism s existence such as tracks, fossilized feces, egg shells, or burrows body fossils: the preserved remains of an organism s body such as bones, teeth, or shells preservation: the act of protecting something from being destroyed 5

6 STUDENT HANDOUT Fossil Puzzler U se the space below to sketch the different sets of fossils 6

7 STUDENT HANDOUT Fossil Puzzler Answer the following questions. 1. What type of fossils did you observe in this activity trace or body? 2. How do you know which type of fossils you observed? 3. How do fossils give clues about the animals or plants from which they came? 4. How did your idea of the creature change as you examined more fossils? 7

8 TEACHER HANDOUT Fossil Puzzler 1. What type of fossils did you observe in this activity? [Trace fossils] 2. How do you know which type of fossils you observed? [They are trace fossils because they do not preserve the remains of the original organism, just impressions.] 3. How do fossils give clues about the animals or plants from which they came? [The shapes, sizes, and other features of fossils provide information about the parts of the animals and plants that formed them, or about the movements of those organisms. Each fossil is like a piece in a puzzle of an entire organism.] 4. How did your idea of the creature change as you examined more fossils? [Possible answer: When I examined more fossils I realized that the creature s head was a different shape than I originally thought. Also, I realized that the creature had a tail. The more fossils I examined, the more I had to modify my idea of the creature.] 8