Geology KWL
Geology: “geo” = earth “ology” = study of
Uniformitarianism: "the present is the key to the past," all things continue as they were from the beginning of the world.
Earth is 4.6 billion years old
Geologic Time Line : 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 You are in the Cenozoic Era Period: a subdivision of the eras in geologic time You are in the Quaternary Period
Evolution: change over time Natural selection: survival of the fittest
Adaptation: a trait that increases the chances that an organism will survive and reproduce Extinction: the evolutionary termination of a species due to a failure to adapt to environmental change
Fossil record: the complete body of fossils that shows how species and ecosystems change over time Fossil types Carbon film Trace fossils Teeth and bones are most likely to be preserved Mold/cast amber
Rocks Review Sedimentary: Crushed rock and organic material layered and compacted into new rock Igneous: Rock formed from melted rock Metamorphic: changed physically and sometimes chemically when subjected to heat and pressure
Law of superposition: oldest rocks on the bottom….youngest on the top! Relative age: using information about rock layers and the fossil record to determine the age relationships between rocks Index fossil: found all over the world for a short period in geologic time Trilobite: ancient aquatic index fossil
Unconformity: gaps in the rock record Mechanical vs. chemical weathering Mechanical: process of breaking big rocks into little ones Chemical: the effect of weathering on molecules and atoms…in nature, moisture, and heat must be present
Movement on the earth Continental drift/plate tectonics: the gradual shifting of Earth’s plates causes continents to change their global positions over time Convergence of plates: the collision of two plates Divergence of plates: two plates are moving away from each other
Pangea: all of the continents were connected. Then they separated to their current positions They are still moving slowly each year!