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 lifeInclude 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=results_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 Ago

Reams or Sheets of Paper

Last ice age ended. 10,000

All dinosaurs are extinct 65 million

Appalachian Mountains formed.

460 million

Algae developed. 1 billion

Unicellular organisms appeared.

3.5 billion

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 Analysis

Write 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.youtube.com/watch?v=y4COsg8o02Q&feature=watch_response_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• Today's 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

4.6

bya-

Eart

h

form

s

THE GEOLOGIC TIME SCALE• At about 4bya, prokaryotes (bacteria!) appear in

oceans.

• ADD “4.0 bya- First prokaryotes” to your timeline

4.6

bya-

Eart

h

form

s4.0

bya-

Fir

st

Pro

kary

ot

es

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

4.6

bya-

Eart

h f

orm

s4.0

bya-

Fir

st

Pro

kary

ot

es

PRECAMBRIAN

542m

ya:

hard

fo

ssils!

THE GEOLOGIC TIME SCALE• The Paleozoic Era was when fish, forests, and

reptiles appeared (542mya-251mya)

4.6

bya-

Eart

h

form

s4.0

bya-

Fir

st

Pro

kary

ot

es

PRECAMBRIAN

542m

ya:

hard

fo

ssils!

Paleozoic Era

251m

ya:

big

exti

nct

ion

THE GEOLOGIC TIME SCALE• The Mesozoic Era was when dinosaurs appeared

(251mya-65 mya)

4.6

bya-

Eart

h

form

s4.0

bya-

Fir

st

Pro

kary

ot

es

PRECAMBRIAN

542m

ya:

hard

fo

ssils!

Paleozoic

251m

ya:

big

exti

nct

ion

65 m

ya:

end

din

osa

urs

Mesozoic

THE GEOLOGIC TIME SCALE• The Cenozoic Era was when mammals thrived.• Humans appeared about 500,000 years ago.

4.6

bya-

Eart

h

form

s4.0

bya-

Pro

kary

ote

sPRECAMBRIAN

542m

ya:

hard

fo

ssils!

Paleozoic

251m

ya:

big

exti

nct

ion

65 m

ya:

end

din

osa

urs

MesozoicCenozoic

500,0

00

ya, firs

t hum

ans

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 Earth's History on the GTS?

Review

• During what Period did the first insects appear?

Review

• In what Epoch do we live in?

Review

• List the Eras in order from most recent to oldest.

Experiment

• In what Epoch did mammals become abundant?

Experiment

• What type of organisms first lived on Earth?

Experiment

• In what Period could you first pick a bouquet of flowers?

Experiment

• How many years ago did the first fish live on Earth?

Review

• What happened 360 million years ago?

Review

• During what Eon did multi-cellular organisms evolve?

Review

• In what period did the first insects live?

Review

• How many years ago did the first amphibian live on Earth?