Earth and Space Science Unit 4 Test Review Questions & Answers

When did mass extinctions occur? - ANSWERSSilurian period, Triassic period, Tertiary period What can be used for evidence to construct the geologic time scale? - ANSWERSfossils, radiometric dating, rock sequences What are the divisions of geologic time? - ANSWERSEons, Eras, Periods, Epoch (in any order) What are the divisions of geologic time from longest to shortest? - ANSWERSEons, Eras, Periods, Epoch (in a specific order) What is a fossil? - ANSWERSdinosaur bone Fossil evidence of horses supports which scientific concept? - ANSWERSEvolution What are the types of fossilization? - ANSWERSPremineralizedation, petrification, formation of crust What is mass extinction? - ANSWERSEcological event in which significant Do all organisms become fossils? - ANSWERSNo, conditions are rare What is an isotope? - ANSWERSAtoms with different number of neutrons (example #12) What is half-life? - ANSWERSTime it takes for half of the parent isotope to turn into daughter What is radiometric dating? - ANSWERSAbsolute method compare ratio Why would a short life isotope be a poor choice for dating many of Earth's oldest rocks? - ANSWERS What is a radioactive isotope? - ANSWERSAtom with unstable nucleus What is a likely application of Uranium-238? - ANSWERSDetermining absolute age of igneous rocks What is the age of the Earth? - ANSWERS4.6 billion years What is the principle of original horizontality? - ANSWERSIgneous intrusion (dike) is longer than cut layers What is uniformitarianism? - ANSWERSProcesses in past continue today What is the principle of original horizontality? - ANSWERSSedimentary rocks form layers What is the principle of superposition? - ANSWERSYoungest layers on top Which processes have gradually shaped and reshaped the Earth's surface over millions of years? - ANSWERSRain, ice, wind What is catastrophism? - ANSWERSSudden singular events shaped Earth What is the principle of inclusions? - ANSWERSChocolate chip paradox- younger rocks on top and older ones on bottom How do stromatolites help scientists explain the formation of Earth's atmosphere? - ANSWERSPhoto synthetic organisms added oxygen What was the composition of Earth's first atmosphere? - ANSWERSHelium and hydration What metals make up Earth's core? - ANSWERSHeavy metals What caused oxygen levels to increase in the early atmosphere? - ANSWERSBacteria What was the most significant contributor to the formation of Earth's early atmosphere? - ANSWERSVolcanic eruptions