Past Biomes and Fossils (Utah State Core , , )

Transcription

1 1 Fourth Grade Past Biomes and Fossils (Utah State Core , , ) Day One: Objective: What is a fossil? Discussion: Ask students what a fossil is and list their answers and examples on the board. Fossils have intrigued and challenged man for centuries. Found worldwide, in all varieties, sizes and shapes, they stir the imagination of all who find them. Their mystery drives scientists and amateurs alike to continually search for and study them. What is a fossil? Any preserved remains from organisms, including traces or imprints, are known as fossils. These remains may include bones, teeth, footprints, impressions, castings, shells and even dung. Fossils are our only guide to the life forms that existed in the first 3.5 billion years of earth's history. Fossils are studied by scientists known as Paleontologists. These scientists may also have a background in geology, zoology, biology, botany or ecology. Activity: Play fossil not a fossil. Hold up a variety of objects and have students tell you why it could or could not be considered a fossil. Hold up a rock, a plastic bottle, a bone, a handprint in clay, a leaf, a leaf imprint (make one by doing a crayon rubbing), a shell, a piece of rusted metal, a stuffed dinosaur, etc. Day Two: Objective: Observation of different fossils Activity: Utah fossil kits will be available for teacher check out from the museum starting in Until then gather fossil samples from school and district resources or have students bring in samples from home. Day Three: Objective: How fossils are made Discussion: The Fossilization process: 1. CARBONIZATION is where most of the flattened specimen dissolves into the surrounding material, leaving a residue behind, such as seen in plant fossils. 2. PERMINERALIZATION occurs when mineral-rich water fills the pores in the specimen. With pressure and time, the minerals solidify, making a fossil.

2 2 3. RECRYSTALIZATION happens when minerals in permineralized fossils undergo chemical changes to more stable mineral forms. Some details of the fossil may be lost, but the overall fossil shape remains. 4. DISSOLUTION AND REPLACEMENT occurs when the specimen dissolves completely, leaving a cavity in the sediment, which fills with minerals, making a cast in the exact shape of the dissolved specimen. 5. TRACE FOSSILS result when footprints, tail prints, leaf impressions, etc., are left in soft sediment which quickly solidifies and is buried. Under the right conditions, they can be preserved as stone, looking much as they did when they first occurred. 6. PICKLING is a compositional change due to immersion in a liquid. This most often is seen in amber where the specimen becomes entrapped in the viscous material. HOW CAN SOMETHING BECOME A FOSSIL? **** First, it has to die. **** But that's the easy part. Afterwards, it has to be really lucky. Though not all the following steps are absolutely necessary for fossilization, skipping any of them greatly lowers the "fossilization potential". 1. It needs to be buried rapidly. It then won't be eaten and scattered around. Floods, landslides or volcanic ash are good for burying, but dying with a quick burial in water is best. 2. There are always more plants and plant-eaters than meat-eaters. This increases their chances of meeting all the right fossilizing conditions. 3. It should have hard parts, like shell or bone, because soft parts don't fossilize well. 4. If it's buried on land, it has a good chance of erosion wearing it away to nothing. And even if it's buried on land deep enough to escape erosion, it might be so deep that increased temperature will destroy it. Activity day one: Make different types of fossils on the first day of the activity and excavate them the second. Have students bury a hollowed out egg in a pile of sand. A hollowed egg makes burial and excavation more difficult and realistic because dinosaur bones are fragile and usually excavated in many pieces. To hollow an egg, poke a small hole in each end of the egg then gently blow into one hole and empty the contest into a bowl. Have them bury a plastic dinosaur in plaster-of-paris (fill a paper cup ½ way with plaster insert the dinosaur and finish filling the cup). Have them roll out molding clay and make an imprint of a dinosaur foot using their hand or imprint another object into the clay. (suggestion: coat hand or object with petroleum jelly for easier removal of object and plaster). Once imprint is made pour mixed plaster-of-paris over the top and let it dry. Day Four: Objective: What is a paleontologist?

3 3 Discussion: Define what a paleontologist is: a scientist who studies dinosaurs; excavates, digs, builds, names, and discovers all types of dinosaurs. Today have the students be a paleontologist and have them go on a hunt for dinosaur parts. Activity day two: Separate the plaster of-paris and the molding clay. Students will discover both types of imprinted fossils. Challenge students to break away the edges of the plaster using a metal butter knife or pick and leave only the imprint of the foot. Have students uncover the hollowed egg using a metal skewer and a paintbrush. Emphasize the importance of not breaking or scratching the egg, make sure the students completely uncover the egg. Have students find other tools paleontologists use to excavate dinosaur bones. (chisel, hammer, brush, screwdriver) see if students can be resourceful and find a tool in the classroom for discovering their dinosaur in their cup. Day Five: Objective: Predict where fossils are found Discussion: The hunt for fossils is not easy and rarely are true fossils found. Here are some guidelines to help: Egg-shaped rocks are seldom fossil eggs. Fossil eggshell feels and looks like avocado skin. Complete fossil eggs will often show considerable crushing. Except as an occasional flat image, soft-bodied creatures do not fossilize. For instance, a heart-shaped rock is not a fossil heart, and a smooth round rock is not an eyeball! There are a limited number of bone and shell shapes in the world, and a rock that doesn't correspond to one of these shapes is likely not a fossil. Like modern bone, fossil bone is often porous or has a porous pattern. Fossil shellfish, found either loose or imbedded in rock, are usually found where modern shellfish don't exist. Fossils will not be found in igneous or metamorphic rocks. These rocks have been subjected to heat and pressure that fossils cannot survive. Fossils will usually be a different color and texture than the surrounding rock. So a "fossily-looking" shape that looks like the rest of the rock is very likely not a fossil. Visit the North American Museum of Ancient Life Focus on Identification of Fossils. Look for Utah originals in the exhibit. Request Casting and Molding in the Discovery Room, (there is a cost of $0.50 per student to cover cost of materials). Students take the mold home.

4 4 Day One: Objective: Discussion Panel Follow Up to the museum visit Discussion: Recap the students experience at the museum allow them time to talk and discuss what they saw and learned. Questions for discussion could include if they found all the Utah Fossils. What dinosaurs do they remember the most? Was this dinosaur located somewhere near Utah? How can trilobites be found in Utah if they lived in the water? What about the animals from the Cretaceous Ocean that were found in Kansas is this answer similar to the trilobite discovery in Utah? Day Two: Objective: Define Extinct Activity: What is extinction did you see the extinction exhibit at the museum? What was your pledge for the future? Make a pledge as a class to prevent future extinction. Research extinction and try to find some specific to Utah. Green River and Utah Cambrian are excellent examples. Discussion: After 550 million years of natural history, the Earth has possibly hosted ten billion different species of plants, animals, bacteria, and other organisms. We know very little about this enormous diversity of life. In fact, we don t even have a good idea of how many species currently share the Earth with us. It may be ten million, thirty million, or many, many more. One thing appears certain: species are disappearing faster today than at any time during Earth's history. Many of these species are insects that vanish before we ever discover them, destroyed when tropical forests are leveled by logging or farming. The current rate of extinction has been estimated at 10,000 times the average rate of extinction in the fossil record. By the year 2050, fifty percent of all species currently on Earth may have disappeared. Human activity is the primary cause of modern extinction, so we must learn quickly to take better care of this planet.

5 North American Museum of Ancient Life Fourth Grade Molding and Casting has a fee of $0.50. If you complete the task of Casting and Molding, tell which mold you chose? In the Bone Cabin Quarry spend some time quizzing your knowledge in the fossil not a fossil and real vs. cast exhibits. Did you guess correctly? Every Time Most of the Time Some of the Time Rarely Many fossils are found in Utah. As you visit the rest of the museum focus on locating Utah s Ancient History. Notice the Carboniferous Forest fossils from Lehi, Utah. Find other examples below, check the box when you have located these pieces of Utah s History. Utah s Cambrian Brachiopod Eocrinoid Trilobites Annelid Worm Mesozoic Jurassic Period Stegosaurus (Adult & Baby) Camarasaurus Utah Raptor Gastonia (Adult & Juvenile) Sauropod Tracks (Carbon & Emery County) Bonus Question: What does a Ichnologist study? Cenozoic Animals Uintatherium Utah Lake Sculpin