Geologic Evidence of Change Over Time FOSSILS Wake

Geologic Evidence of Change Over Time - FOSSILS Wake County 8 th Grade Science Curriculum

Fossil: preserved remains or traces of living things • Most fossils form when living things die and are buried by sediment; over time the sediments harden • Fossils are only found in sedimentary rock. WHY?

Change Over Time Geologic Evidence Different kinds of fossils are: 1. Mold: a hollow area in sediment in the shape of an organism or part of an organism; formed when the organism makes an indentation that turns to rock over time Cake mold www. ammonoid. com

Change Over Time Geologic Evidence Cast: a solid copy of the shape of an organism; made by filling in a mold with minerals that later turn to rock. esp. cr. usgs. gov Mold Cast

Change Over Time Geologic Evidence 2. Petrified fossil: minerals replace all or part of an organism en. wikivisual. com You can see the rings. www. alaska. edu

Change Over Time Geologic Evidence 3. Carbon film: an extremely thin coating of carbon on rock; made when an organism is squeezed by rock until only carbon remains www. geology. ohio-state. edu

Change Over Time Geologic Evidence 4. Trace fossil: evidence of activities of ancient organisms; may be tracks, burrows, nest, or trail igs. indiana. edu Fossil burrow Fossil tracks

Change Over Time Geologic Evidence 5. Preserved Remains Amber: a hardened resin, or sap, of evergreen trees; organisms that get trapped in the sticky substance pixdaus. com becomes part of the rock www. ambermine. com

Change Over Time Geologic Evidence Frozen remains: organisms caught in ice or snow Adult mammoth Frozen baby mammoth flickr. com www. cryptomundo. com

Change Over Time Geologic Evidence Fossil record: the complete body of fossils that shows how species and ecosystems change over time www. rockandwater. com anthropology. net images. mooseyscountrygarden. com

Change Over Time Geologic Evidence • The fossil record shows that fossils occur in a particular order: older rocks contain simpler organisms and younger rocks contain more complex organisms. WHY? ? • The fossil record provides evidence to support evolution (the gradual change in living things over long periods of time). • {Everything we are studying shows evolution as a change over time – do not bring religion into it We have to teach the curriculum. Everything is a scientific theory. What does this mean? }

Change Over Time Geologic Evidence How do fossils give us the age of organisms that lived in the past? Is this fish fossil a few thousand years old or a few billion years old? www. treasure-hunting-team. com

Law of Superposition • The Law of Superposition: a given rock layer is older than the rock layer above it. • Think about your dirty clothes in your laundry basket? Where is the oldest clothes compared to the clothes you wore yesterday?

Uniformitarianism • Geologic process that happened in the past that are still present now. Examples: • Weather and erosion today also shaped Earths surface millions of years ago • Continental Drift…continues today as it did millions/billions of years ago

Change Over Time Geologic Evidence Dating Rocks and Fossils Relative Dating: uses information about rock layers and the fossil record to determine the age relationships between rocks Absolute Dating: any method of measuring the age of an event or object in years