GEOL 1425 1st EditionExam # 3 Study Guide Lectures: 12- 15Lecture 12- Earths oxygenated atmosphere came from early life- Red beds: unusual stream deposits of sandstone and shale’s bound together by iron oxide comments, which gives them the red color. The present of iron oxide in these deposits indicates there must have been oxygen in the atmosphere- Evolutionary radiation: rapid development of new types of organisms from a common ancestors- Evolution: systematic change in organisms over many generations- Natural selection: process by which populations of organisms adapt to changes in theirenvironment.Lecture 13- The universal ancestor gave rise to the three major domains of life: Bacteria, Achaea, and Eukaryotes. - Eukaryotes have a more complex cellular structure, which include a cell nucleus that contains genes. - Eukaryotes are the youngest of the three domains of life.- Microfossils: the traces of individual microorganisms preserved in rocks. - Microorganisms that live in extreme environments are almost exclusively archae and bacteria.Lecture 14- An earthquake occurs when rocks under stress fail along a geologic fault.- Elascity: the blocks would spring back and forth to their un-deformed, stress free shape if the fault were to suddenly unlock. - Focus: point at which fault slipping begins- Epicenter: geographic point on earth’s surface directly above the focus. - Seismograph: reads seismic waves- 3 types of seismic waves, P waves, S waves, and surface waves.- P waves (primary waves): compressional waves, first wave to arrive, travel through solid, liquid, or gas and push or pull particles of matter in the direction of their path. - S waves (secondary waves): shear waves that place material at right angles to their path of travel. Can only travel through solids. - Surface waves travel through earth’s surfaceLecture 15- S wave shadow zone: beyond 105 degrees from the earthquake focus. - Upper mantle: made primary of periodite, a dense ultra-mafic rock composed primarily of olivine and pyroxene.- Low velocity zone: near base of lithosphere S wave velocity abruptly decreases, marking the start of a low velocity zone.- Transition zone: mantle properties change slowly as depth increases- Lower mantle: relativity homogenous region, below transition zone - Conduction: heat occurs when thermally agitated atoms and molecules jostle one another- Convection: transfers heat more efficiently than conduction because the heated material itself moves, carrying its heat with it.- Geothermal gradient: increase in temperature with depth in earth’s