Continental Drift video that are scientifically Hypothesis - - PowerPoint PPT Presentation

Continental Drift Hypothesis

Alfred Wegener’s Evidence

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Compare and Contrast

• Watch the following video.

Write down the parts of the video that are scientifically accurate, and those that are scientifically inaccurate.

Compare and Contrast

• What parts of the video were

scientifically accurate?

Earth’s continents used to be connected Continents were separated by movement under the crust There are layers within

• ur planet

The inner core is a solid ball of iron and nickel

Compare and Contrast

• What parts of the video were NOT

scientifically accurate?

The speed of the continental break-up was exaggerated South America and Africa broke apart 225 million years

• ago. Giraffes have only been on Earth for about 6 million

years. A squirrel-ancestor didn’t cause the break-up Continental Drift is not responsible for man-made statues

Plate Tectonics

Alfred Wegener:

(1880-1930)

Famous for proposing Continental Drift Theory, and the Theory of Pangaea.

Three Pieces of Evidence

• 1. Geometric Fit of Continents
• 2. Fossil and Geologic Record
• 3. Ancient Climates

Three Pieces of Evidence

• 1. Geometric Fit of the

Continents

Geometric Fit

Pangaea was a SUPER CONTINENT on the Earth 225 million years ago.

Geometric Fit

Pangaea was not the first supercontinent, and it will not be the last.

Pannotia—600 million years ago Rodinia—750 million years ago

Geometric Fit

After about 25 million years Pangaea separated into TWO major continents: Laurasia and Gondwanaland

Geometric Fit

Can you see the 7 continents we have on Earth today?

1 2 3 4 & 5 6 7

Geometric Fit

Around the same time the dinosaurs went extinct (65 million years ago) the Earth’s continents were still moving!

Geometric Fit

Wegener noticed that the coasts of South America and Africa looked like puzzle pieces.

Three Pieces of Evidence

• 2. Fossil Record

Fossil Record

• Wegener used fossils, land features, and climate

to come up with the Theory of Continental Drift.

• One of the fossils he used as evidence was of the

Mesosaurus reptile!

Fossil Record

• Fossils of the Mesosaurus have

been found in South America and in Africa.

Fossil Record

Other CRAZY fossils!

• Lystrosaurus: Found in Antartica,

Australia, Madagascar, and Africa

Other CRAZY Fossils!

Cynognathus: Found in South America and Africa

Landform Evidence

• Wegener also used landforms, like

ancient rivers, glacier carvings, and mountain ranges that lined up on opposite continents!

The pink areas show places with identical rock formations

Scotland Norway

Kukenan Tepuy in Gran Sabana National Park, Venezuela Drakensburg Mountains, South Africa

Three Pieces of Evidence

• 3. Ancient Climates

Ancient Climates

By studying the rock layers in various places, scientists can determine what the climate use to be like.

Ancient Climates

Read “What is Paleoclimatology?” Annotate your notes:

+ New Information

Information I already knew Information I want to know more about

Ancient Climates

• 1. Where has Earth kept a record of

past climate conditions?

Tree Rings Coral Reefs Glaciers Lake Sediment

Ancient Climates

• 2. How has polar ice changed over the

last 2 million years?

The areas colored white were covered by an ice sheet between 70,000 and 20,000 years ago

Ancient Climates

• 3. What has

happened to temperatures during the 20th century?

Ancient Climates

Another piece of evidence for ancient climates is Glacial Striation; scratches made in rock as a glacier moves down the mountain

Ancient Climates

When glacial striations are mapped, it shows an ancient glacier covered much of Pangaea

Putting all evidence together…

http://scotese.com/earth.htm

See what your location looked like during different time periods:

Was the theory accepted?

• No! Alfred Wegener’s theory was

not well accepted at the time because there was NOT enough evidence.

• Wegener could not explain the

force that was causing the continents to move.

Let’s Summarize…

⦿Wegener used 3 pieces of evidence to

support his theory: ⦿Geometric Fit of the Continents ⦿Fossil and Rock Record ⦿Ancient Climate Data

⦿Other scientists did NOT accept the

Theory of Continental Drift