EARTH’S HISTORY
SECTION 4.1
http://go2add.com/paleo/TheEarliestLife.php
OBSERVE
• Look at the Picture on page 74:
• What does this photograph show?
• What features make you think it is a bird?
• How do you know it’s a fossil?
• How do you think this fossil was formed?
• What does the picture have to do with the subject of this
chapter? (Earth’s History)
http://natgeoeducationblog.files.wordpress.com/2013/01/fossil.jpg
TIME TO CHANGE
Look around your classroom and look outside.
1. Make a list of ten objects or conditions inside and
outside your classroom that don’t seem to
change from day to day.
1. Write down one way that each item could
change and how long it would take.
http://www.pitara.com/wordpress/wp-content/uploads/2013/12/earth-110_1.gif
CHANGE
• What do you think of when you hear the word
change?
• How will you change in the next 10 years?
• How will the Earth change in the next 10 years?
• Does the way you change differ from the way the
Earth changes? How?
http://mmdl.org/view/rosterchange
AGE OF THE EARTH
•
•
•
•
The Earth is 4,600,000,000 years old.
Earth’s history is very long
It’s longer than human experience.
Geologic Time- special name for the time scale of
the history of the earth and its life.
http://2.bp.blogspot.com/-UidFJH3abVM/Ty75cSC4G-I/AAAAAAAAAAY/Cm4MB1-BepQ/s1600/Earth%2527s+Structure.png
ORIGIN OF THE EARTH
• 5,000 million years ago there was a cloud of matter
spinning in space.
• It began to collapse and drew in matter from the
surrounding area to the center from a gravitational
pull.
• As this happened the center became hot and
dense and through the process light and heat were
released creating our sun.
• Surrounding matter began to clump and then
planets and eventually Earth was born.
http://science.howstuffworks.com/environmental/earth/geophysics/earth6.htm
EARTH’S EARLY HISTORY
• During the first billion years
•
•
•
•
No oceans
No continents
No atmosphere
Only volcanoes constantly erupting and spewing gases
• Then an atmosphere started to form and some
gases condensed creating water.
• ~3,800 million years ago:
• First land masses had formed from volcanic eruptions.
• First living things came into being in oceans
• Some producing Oxygen
https://astrobiology.nasa.gov/media/medialibrary/2011/12/49c2fe43b1581ebd6e4daab182edb346-image1.jpg
EARTH’S EARLY HISTORY
• ~ 2,000 million years ago:
•
•
•
•
•
Earth similar to today
No organisms on land yet
Mountains and Rivers existed
Atmosphere contained Oxygen
Energy from the sun created weather patterns.
http://sachtimes.com/en/images/140275606114027472660.jpg
CHANGES ON THE SURFACE
• Over the last 2,000 million years:
• Change has continued but changes have followed regular
patterns.
• 4 types of surface changes:
•
•
•
•
Weather and Erosion
Deposition
Formation of Sedimentary Rock
Uplift
http://www.slcschools.org/departments/curriculum/science/Grade-3-to-6/Grade-5/images/changing-earths-surface_000.jpg
WEATHER AND EROSION
• Weathering- rocks are broken up into smaller
particles by the action of water, atmosphere, and
organisms.
• Earth’s surface can be shaped by weathering and
erosion, where weathering happens first, then
erosion happens second.
• Erosion- smaller particles of rock are displaced by
moving water, wind, or ice.
• Sediment- particles carried away by erosion.
• Weathering and erosion work slowly, but over time
can cause major changes.
http://nortelvoicemail.files.wordpress.com/2012/07/delicate-arch-arches-national-park-utah.jpg
DEPOSITION
• Particles of erosion travel to low places because of
gravity.
• Deposition- buildup of eroded particles or sediment.
• Deposition is a building-up process.
• Slow process that is happening all of the time.
http://www.passmyexams.co.uk/GCSE/physics/images/rock-cycle-03.jpg
FORMATION OF SEDIMENTARY ROCK
• Sediment builds up over long periods of time and it
causes horizontal layers on the earth.
• With newer layers on top of older ones.
• With more layers on top pressure
is put on the lower layers
• Pressure causes sediments to compact
together and become rock.
• Sedimentary Rock- rock that forms from sediment.
• The deeper the layer of sedimentary rock, the older
it is.
http://museumvictoria.com.au/pages/17094/ImageGallery/1pic-43069.jpg
UPLIFT
• Why do we have mountains and high places?
• Why isn’t the world flat?
• Uplift- process where parts of the crust are raised
above others.
http://www.ucmp.berkeley.edu/education/dynamic/session4/images_sess4/himalayas1.gif
QUESTIONS
• What are the four ways that cause Earth’s surface
to change?
• Which comes first, weathering or erosion?
• How are weathering and erosion different from
deposition?
• What would the world look like without uplift?
• Where can we see examples of sedimentary rock?
http://images.clipartpanda.com/red-question-mark-clipart-pT5nqXATB.gif
CHANGES IN LIFE
• Organisms have lived on Earth for millions of years.
• We can see evidence of life through fossils.
• Fossil- remains or traces of an organism, found in
rocks of the crust, that lived in the past.
• Most are formed when organisms were buried in the
sediment.
• A fossil is as old as the rock it’s found in.
• Studying of fossils shows change in organisms over
time.
• Many no longer exist (extinct).
http://evolution.berkeley.edu/evolibrary/images/evo/whaleancestors3.gif
CHANGE IN CLIMATE
• Climate has varied a lot throughout the history of
the Earth
• It was both dry and cold and wet and warm.
• When dry and cold:
• Polar ice caps increased in size
• Ice sheets spread to middle latitudes
• Ice Age- periods where ice caps and ice sheet
increase.
• Most changes in climate are slow
• Humans and technology have changed climate on
a local and global scale in a faster process.
http://upload.wikimedia.org/wikipedia/commons/b/b3/MonthlyMeanT.gi
ON ICE
• When sheets of ice expand and advance from the
poles, much of Earth’s water is frozen in ice.
• What do you think might happen to the ocean
levels?
• How might this affect shoreline erosion?
• State a hypothesis to explain your reasoning.
http://theresilientearth.com/files/images-2013/iceage_earth.jpg
WHAT HAVE WE LEARNED?
• From what did the earth form?
• What does erosion do to the earth’s surface?
• How would a layer of sedimentary rock formed from
mud be different from one formed from sand?
• Using words and arrows, draw a diagram to show
how weathering, erosion, deposition, sedimentary
rock formation, and uplift are related?
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ49yhOMIR7lYyyjvkivYKv8E6gQtjXrfZIRS5WA_JGoq76lhe6