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Quiz/Review. Get out a small piece of paper and put your name on it. When the bell rings, the quiz will begin. Question 1. When did the last major eruption of Mt. St. Helens occur?. Question 2. What killed most people in the major eruption of St Helens. Question 3.
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Quiz/Review • Get out a small piece of paper and put your name on it. • When the bell rings, the quiz will begin.
Question 1 • When did the last major eruption of Mt. St. Helens occur?
Question 2 • What killed most people in the major eruption of St Helens.
Question 3 • What causes a major landslide?
Answers • 1980 • Lahar, pyroclastic flow, flooding, ash • Slope, precipitation, human impact
Mass Extinction Cretaceous–Paleogeneextinction (K-T) What killed the dinosaurs? (Formally called the Cretaceous-Tertiary extinction)
Maps Meteor impact 65.5 million years ago.
What is… • A Meteor impact in Mexico 65.5 million years ago. • Killed 65-70% of all species on Earth. • 90% of everything ever alive is now extinct! Extinctions are common. • Five major extinctions in the past and many smaller ones.
When… • Earth is 4.6 Billion Years old. • Life on Earth began in the Paleozoic (570 million years ago) • Dinosaurs were present on Earth around 245 million years ago and lived for about 180 million years. • Humans have only been on Earth for maybe 10,000 years!
Time line • Very controversial! • Some say fast (few years) some say slow (millions of years)?! • The fossil record is incomplete, so difficult to say something is present or not.
What causes this event? • Meteor (widely accepted) • Volcanism (flood basalts) • Deccan Traps (dark purple) • Climate Change • Atmospheric changes from othercauses. • Sea level change • Sea level fell after 65 mya • Mega-Tsunami • Deposits of sea sediments in mountains of Mexico
Who is affected? • Marine Invertebrates - 60% species extinct. • Fish - 80% survived • Terrestrial Invertebrates – Not determined • Plants - 57% plants extinct • Amphibians – Most survived • Mammals - • Reptiles – Almost all species become extinct. • Two major survivors • testudines - turtles • lepidosaurs – lizards and snakes.
Facts • All current data and theories are based off of fossil evidence. • The K-T boundary is identifiable in North America: • By lack of ferns before, but abundant after. • Hell creek, Montana • Pollen levels in rocks and ice Hells creek formation
What If... • 5 previous major mass extinctions • Some say we are in one now? • Climate change • Sea level change • Loss of resources • Over population
Works Cited • http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event • http://science.nationalgeographic.com/science/prehistoric-world/mass-extinction/ • http://www.msnbc.msn.com/id/35712419/ns/technology_and_science-science/t/rock-solid-case-asteroid-killed-dinosaurs/ • http://www.staff.science.uu.nl/~rutte101/stuff/manicouagan/extinctions.png