S&S Unit 2 Test - Geologic Time and Radiometric Dating PDF

Name: Siena & Sammy Date: 10/18/24 Subject: Science **Test - Geologic Time and Radiometric Dating Study Guide　Geologic Time** 1\. How and when did Earth come to be? **4.6 billion years ago. Formed from a supernova (giant star explosion) which left behind a giant cloud of elements which formed...

Name: Siena & Sammy Date: 10/18/24 Subject: Science **Test - Geologic Time and Radiometric Dating Study Guide　Geologic Time** 1\. How and when did Earth come to be? **4.6 billion years ago. Formed from a supernova (giant star explosion) which left behind a giant cloud of elements which formed all the planets.** 2\. Understand the difference between eons, eras, periods, and epochs. **Eon =** **Era =** **Period =** a\. Know the names and basic facts about the four eons **Hadean -** No life/hell **Archean -** First life! Solid rock, oceans formed **Proterozoic -** Cyanobacteria started producing Oz which allowed more life to form and filled the atmo with air **Phanerozoic -** Our current eon! All big life & oxygen in atmo. We lump the first 3 eons into "Precambrian Time" b\. When are we? **Phanerozoic eon** **Cenozoic era** **Quarterternary Period** **Holocence epoch** 3\. What is the major difference between the early and late pre-Cambrian eras? a\. What was earth like? (Atmosphere, land, water, life.) 4\. Which time period has taken up the most of Earth's history? **Precambrian time: 88.6% of earth's history** 5\. What is the major difference between the types of life in the late pre-Cambrian era and every era following? 5\. What is the major difference between the types of life in the late pre-Cambrian era and every era following? 6\. When (eon, era, period) did humans first evolve? **Phanerozoic** 7\. What marked the end of the Mesozoic era? **Massive meteor that wiped out all of the dinosaurs, and 80% of life** 8\. Know which time period each of the following are associated with: a\. Continents forming **Archean 2nd eon** b\. Oxygen rising **Proterozoic 3rd eon** c\. First life **Archean 2nd eon** d\. First Trilobites **Archean 2nd eon** e\. First Dinosaurs f\. The "Age of Mammals" 9\. What is the Cambrian explosion? 10\. What is an extinction event/mass extinction? **Huge asteroid** 11\. Be comfortable using the Geologic Time Scale as a tool to identify the significance of Earth's history. You will receive a copy of the Geologic Time Scale to Reference 12\. What is the difference between the Permian-Triassic Extinction and the Extinction of Dinosaurs at the end of the Mesozoic Era? Dating Rocks and Fossils 1\. What is relative dating and relative age? **Relative Dating:** Comparing between rocks to see which are older + younger **Relative Age:** The relative age of a rock is its age compared to the age of other rocks 2\. What is absolute dating and absolute age? **Absolute dating finds out the actual age of rocks/fossils by using radioactive isotopes and their half-lines to determine the age.** **Absolute age: The Absolute age of a rock is the number of years that passed since the rock formed** 3\. What is the law of superposition? **Younger rocks are above older rocks but this is not always true, because erosion and earthquakes could alter the placement of the rocks.** 4\. What is radioactive dating? **Comparing rocks to other rocks to know which are older and younger.** a\. Understand half-life. **Time it takes for half of an isotope to decay** b\. Be able to determine the half-life of an element given a graph. 5\. What are fossils? a\. Be able to identify fossil types b\. Index fossils Help geologists match & date rock layers