1) The document discusses different methods by which fossils can be preserved, including freezing, drying, exposure to asphalt or amber, and permineralization. 2) It provides background information on identifying fossils and comparing them to living organisms based on similarities and differences. 3) The activities described involve students making impressions of shells in salt dough to create their own fossils, comparing the originals to the fossils, and analyzing similarities and differences.

1. Fossil History Heather Jackson Mr. Sandrick 9/30/09

2. Indicator 5.4.8-Observe that and describe how fossils can be compared to one another and to living organisms according to their similarities and differences. Taken from: http://dc.doe.in.gov/Standards/AcademicStandards/StandardSearch.aspx Link to Activity: http://www.indianastandardsresources.org/files/sci/sci_5_4_8.pdf Science Standard 4-The Living Environment

3. Definitions Organism: a form of life considered to exist; an animal, plant, fungus, protistan, or moneran. Fossil: any remains, impression, or trace of a living thing of a former geologic age, as a skeleton, footprint, etc. Living: having life; being alive; not dead Extinct: no longer in existence; that has ended or died out Taken from: http://dictionary.reference.com/

4. Background Information pg. 1 Freezing (refrigeration)-This is the best means of preservation of ancient materials. It happens only rarely. The animal must be continually frozen from the time of death until discovery. That limits the possibilities to cold hardy animals from the last ice age. There have been remarkable discoveries of mammoth and wooly rhinoceros found in ice from Alaska and Siberia. Specimens with flesh, skin, and hair intact have been found. Some of these finds suggest that they were flash frozen, with food still in the mouth and stomach. Drying (desiccation)- Mummified bodies of animals including humans have been discovered in arid parts of the world. The soft tissues including skin and organs are preserved for thousands of years if they are completely dried. Asphalt- In what is now downtown Los Angeles lies a 23 acre park called The La Brea Tar Pits, officially Hancock Park. Within the park are over 100 pits filled with sticky asphalt or tar. The tar pits were formed by crude oil seeping through fissures in the earth. The lighter elements of the oil evaporate leaving thick sticky asphalt. The pits are famous for the number and high quality of Pleistocene fossils that have been pulled from the pits. The fossils date between 10 and 40 thousand years old. Asphalt is an excellent preservative. Bones, teeth, shells, the exoskeletons of insects, and even some plant seeds have been pulled from the pits. Taken from: http://www.fossils-facts-and-finds.com/

5. Background Information pg. 2 Amber- Insects, spiders, and even small lizard have been found, nearly perfectly preserved in amber. Picture this scenario: A fly lands on a tree branch in an area that is now the Baltic sea. While looking for food it steps in sticky sap that the tree has made to protect itself from fungal infection. As the fly struggles to escape it becomes more and more entombed in the sap until it is completely engulfed and suffocates. The tree eventually dies and falls into the swampy water from which it grew. Over the course of millions of years the tree along with countless others becomes a coal deposit and the sap with our fly inside is polymerized and hardened into amber. As more time passes the coal bed is submerged as the sea level rises. Eventually the currents uncover the coal bed, slowly eating into the Surface, little by little. When the erosion reaches the amber it floats to the surface because it is lighter than the salty water. It is then washed ashore where it can be found. Carbonization (distillation)- In this process of fossilization plant leaves, and some soft body parts of fish, reptiles, and marine invertebrates decompose leaving behind only the carbon. This carbon creates an impression in the rock outlining the fossil, sometimes with great detail. Permineralization-This is the most common method of fossil preservation. Minerals fill the cellular spaces and crystallize. The shape of the original plant or animal is preserved as rock. Sometimes the original material is dissolved away leaving the form and structure but none of the organic material remains. Taken from: http://www.fossils-facts-and-finds.com/

6. Earth’s oldest fossils are the stromalitesconsisting of rock built from layer upon layer of sediment and other precipitants. Based on studies of now-rare (but living) stromatolites (specifically, certain blue-green bacteria), the growth of fossil stromatolitic structures was biogenetically mediated by mats of microorganisms through their entrapment of sediments. However, abioticmechanisms for stromatolitic growth are also known, leading to a decades-long and sometimes-contentious scientific debate regarding biogenesis of certain formations, especially those from the lower to middle Archaean eon. Taken from: http://en.wikipedia.org/wiki/Fossil#Earliest_fossiliferous_sites Background Information pg.3

7. Fossil History Google images: http://images.google.com/imghp?hl=en&tab=wi

8. Preparation Collect pictures and similar specimens of both fossil and living organisms. Label and pair each specimen into related organisms. Place the pairs along with pictures around the room. Prepare salt dough (230 ml flour, salt and water for every 4 students). Knead until elastic Form a ball and cover with a moist paper towel. Pass out to each student. Taken from: http://www.indianastandardsresources.org/files/sci/sci_5_4_8.pdf

9. Ask students what fossils are and what they could learn from comparing fossils. Tell students that they will be investigating the similarities and differences of two fossils using the Venn diagram on the worksheet. After the students are finished ask them about the similarities and the differences that they found and why they think they are different. Taken from: http://www.indianastandardsresources.org/files/sci/sci_5_4_8.pdf Fossil Comparison

10. Fossil Creation Hand each student a paper towel, a shell, and a ball of dough. Students should write their name on the paper towel then place the ball of dough in the middle. Have students press the dough into a disc until it’s 2cm thick. Students should press the outside of their shell firmly yet gently into the dough to make an impression. (while they are doing this the teacher should prepare a mixture of plaster of paris) Fill the impressions of the shells made by the students with plaster. Then place the molds in a warm dry place to dry After the plaster has dried, have students peel the salt dough away gently and then throw it away. Observe the similarities and differences between the original shell and the fossil Taken from: http://www.indianastandardsresources.org/files/sci/sci_5_4_8.pdf

11. Resources Everything Fossils: http://www.fossils-facts-and-finds.com/ Fossil Images-Pictures of Fossils: http://www.fossilmuseum.net/FossilGalleries.htm Fossils for Kids: http://www.fossilsforkids.com/ How Fossils were Formed: http://www.enchantedlearning.com/subjects/dinosaurs/dinofossils/Fossilhow.html Science Daily: http://www.sciencedaily.com/news/fossils_ruins/