Geologic Time Scale- 10/18/11Bell Ringer-How old do you think the Earth is, according to geologists?2. How old do you think life is, according to geologists?3. What is the law of superposition? What does this law say?
Geologic Time Scale- 10/18/11 Make a timeline of your life Include At least 5 major (important) events
THE EARTH IS POWERFUL• As you watch this, imagine you are inside this building in Japan. – How would it feel to be there? http://www.youtube.com/watch?v=pytPBwY0Sw8& feature=BFa&list=PL3F819A227D58B74F&lf=result s_main
THE EARTH IS OLD• Each table has a list of @’s on it.• 2,000 @ signs on this paper, 50 per row.• Starting at the top left, label as many @ signs as you can with events of the past 2,000 years in 5 minutes: • Your birthday • Your parent’s/grandparents’ birth years • Historical years you remember (1969, 1945, 1776, etc.)
Examples: Important Dates• 1969- Moon Landing• 1955- Polio Vaccine• 1945- end of WWII• 1912- Titanic Sinks• 1860- Start of Civil War• 1674- Bacteria are first seen by people• 476- Roman Empire Collapses
THE EARTH IS 4.6 BILLION years old!• How many reams of paper would you need, full of “@” signs, to count up 4.6 billion years??
FIND OUT HOW GEOLOGIC TIME LOOKS… in paper! Event # of Years Reams or Sheets Ago of Paper Last ice age ended. 10,000All dinosaurs are extinct 65 millionAppalachian Mountains 460 million formed. Algae developed. 1 billion Unicellular organisms 3.5 billion appeared. Earth formed. 4.6 billion
Testable Question• What is an extinction? What are the major causes of causes of extinctions?
Research/Background Info• Extinction: when a species (plant or animal) disappears from Earth; – 99.9% of all species that have ever lived are now extinct!• Mass extinction: large numbers of species die out in a short time• Almost all extinctions are caused by environmental change
THE EARTH IS POWERFUL• As you watch this, imagine you are inside this building in Chile. – How would it feel to be there? http://www.youtube.com/watch?v=MqkQbAAYsnI& feature=related
Data Collection/Analysis• Create a picture for each of the 8 natural causes of species extinctions in your notebook
Data Collection/Analysis• Natural events that cause extinctions: – Increase/decrease in temperature – Increase/decrease in rainfall – Volcanic eruption – Earthquake – Flooding/drought – Shifting land or sea – Change in food supply – New predator or disease
Data AnalysisWrite Time! (In your notebook, write at least 3 sentences)• What cause(s) do you think is responsible for the extinction of the dinosaurs?• What is the cause of all natural species extinctions (including the dinosaurs)?
Experiment• Extinction of the Dinosaurs! Video clip• http://www.yout ube.com/watch?v =y4COsg8o02Q&f eature=watch_res ponse_rev
Testable Question• What is the Geologic Time Scale? How is it organized?
Research/Background Information• Geologic Time Scale: timeline that organizes the events in Earth’s history• Todays Calendar: – Year, Month, Week, Day• Geologic Time Scale: – Eon, Era, Period, Epoch• Separated by major events: Mass extinctions, development of many new species…
THE GEOLOGIC TIME SCALE• The Geologic Time Scale is the calendar of Earth’s history, organized by important events (extinctions, development of life).• We are going to draw one!• DRAW A LONG LINE ACROSS YOUR PAGE
THE GEOLOGIC TIME SCALE• In a timeline, we put the oldest date on the left and the newest on the right.• The GTS starts at 4.6 bya (billion years ago)• ADD “4.6bya- Earth forms” to your timeline
THE GEOLOGIC TIME SCALE• At about 4bya, prokaryotes (bacteria!) appear in oceans.• ADD “4.0 bya- First prokaryotes” to your timeline
THE GEOLOGIC TIME SCALE• For 4 billions years, life was too small and soft to make fossils.• This time of little fossils from 4.6bya-542 mya is the Precambrian.ADD “PRECAMBRIAN” above your timeline, until 542 mya PRECAMBRIAN
THE GEOLOGIC TIME SCALE• The Paleozoic Era was when fish, forests, and reptiles appeared (542mya-251mya) PRECAMBRIAN Paleozoic Era
THE GEOLOGIC TIME SCALE• The Mesozoic Era was when dinosaurs appeared (251mya-65 mya) PRECAMBRIAN Paleozoic Mesozoic
THE GEOLOGIC TIME SCALE• The Cenozoic Era was when mammals thrived.• Humans appeared about 500,000 years ago. Mesozoic PRECAMBRIAN Cenozo Paleozoic
Analysis:• When you tell someone that something happened a long time ago, how does your version of a long time ago compare to the Earth’s geologic time?• How does the time humans have spent on Earth compare to geologic time as a whole?• Have we been here a long portion of geologic time or only a small period of time? Justify your answer.
Exit TickET EOG Question• The geologic time scale is divided by major changes or events such as:A.mass extinctionsB.the development of one new speciesC.the extinction of one speciesD.a small temperature change
Experiment• In what Period did the first dinosaurs appear?
Review• How do scientists divide Earths History on the GTS?
Review• During what Period did the first insects appear?