Mass Extinction Notes

• 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?
1) 1980
2) Lahar, pyroclastic flow, flooding, ash
3) Slope, precipitation, human impact
Mass Extinction
extinction (K-T)
What killed the dinosaurs?
(Formally called the Cretaceous-Tertiary extinction)
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
Five major extinctions in the past and many smaller ones.
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 other
Sea level change
 Sea level fell after 65 mya
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.
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