1. Weathering Vocab Weathering – Chemical and physical processes that break down rock at Earth’ surface Chemical Weathering – the process that breaks down rock through chemical changes Mechanical Weathering – the process that physically breaks down rocks into smaller pieces Erosion – the removal of rock particles by wind, water, ice, or gravity Flashcards: Picture and word on front and definition on back

2. Fossils Vocab Fossil - evidence of past life preserved in rock. Fossil record - the complete body of fossils that shows how species and ecosystems change over time. Fossilized – the process of becoming a fossil Trilobite – a marine organism that is an example of an index fossil Index fossil – a fossil found in a narrow time range but distributed around the earth; used to date rock layers Trace fossil – a fossilized mark that is formed in soft sediment by movement or actions an animal Ice Core – a cylinder of ice removed from a glacier; contains trapped atmospheric gases to tell us about the climate in the past

3. Law of Superposition VOCAB Law of superposition – the idea that rocks and fossils found in lower layers are older than the rocks and fossils found in the top layers relative dating – a method of dating rocks which can’t give us an actual age, but can tell us whether a rock layer is older or younger than another strata – a certain rock layer unconformity - gaps in rock layers and/or the fossil record intrusion - a rock layer that forms when magma hardens beneath Earth’s surface extrusion - a rock layer that forms when lava flows onto Earth’s surface and hardens radiometric dating – using radioactive elements found naturally in substances in order to determine how old they are. absolute age – the actual age of a rock or fossil

4. Geologic Time Vocab Geologic Time Scales - a record of the life forms and geologic events in Earth’s history Era - a unit of geologic time that includes two or more periods Period - a subdivision of an era Continental Drift - the theory that states that the gradual shifting of Earth’s plates causes continents to move over time Pangaea - The name of the big landmass that broke apart into the current continents Plate Tectonics - large pieces of the Earth’s outermost layer (called tectonic plates) move and change shape

5. EVOLUTION VOCAB Adaptation: a trait that increases the chances that an organism will survive and reproduce Biological evolution: the change over time of living organisms Extinction: The evolutionary termination of a species caused by the failure to reproduce and the death of all remaining members of the species Species: the most specific classification of living things Darwin: a naturalist who proposed and provided scientific evidence that all species of life have evolved over time from common ancestors Natural Selection: survival of the fittest organisms that are the best adapted to their environment and will live long enough to reproduce and pass on those adaptations Theory: a explanation that ties together many hypothesis and observations