Review of Chapter 6 -L4

Review of Chapter 6 L1,L2, L3, & L5

This is a quick recap of the material we detailed during remote learning.

Big Question for Lesson 6

How do scientists study Earth's past?

Lesson 1 Fossils

What are fossils?

What are the kinds of fossils?

What do fossils show?

What are Fossils?

Fossils are preserved remains or traces of living things.

What are the types of fossils?

* Molds and Casts

* Petrified Fossils

* Carbon Films

* Trace Fossils

* Preserved Remains

Multiple Choice

What type of fossil is this?

• petrified

• Carbon Film

• Trace Fossil

• Preserved Remains

• Mold and Cast

Multiple Choice

What type of fossil is this?

• Mold and Casts

• Petrified

• Carbon Films

• Trace

• Preserved Remains

Multiple Choice

What type of fossil is this?

• Mold & Cast

• Petrified Fossil

• Carbon Film

• Trace

• Preserved Remains

Multiple Choice

What type of fossil is this?

• Molds & casts

• Petrified

• Carbon Film

• Trace

• Preserved Remains

Multiple Choice

What type of fossil is this?

• Molds & Casts

• Petrified

• Carbon Films

• Trace

• Preserved Remains

What do fossils show?

The fossil record provides evidence about the history of life and past environments on the Earth. It also shows how different goups of organisms have changed over time.

Multiple Select

Which of the following is something fossils can tell us?

• They can tell us about past organisms

• They can tell us about past environments

• They tell us how groups of organisms have changed over time.

• They can tell us about future events.

Lesson 2 The Relative Age of Rocks

How old are rock layers?

How can rock layers change?

How old are rock layers?

Relative and Absolute Age

* Relative age is the age of a rock compared to ages of other rocks.

* Absolute age is the of a rock in years.

Multiple Choice

This fossil is 25 million years old. Is that a ...

• relative age

• absolute age

Multiple Choice

The rock layer on the bottom is older than the rock layer on top of it. This is ...

• relative age

• absolute age

The law of superposition

This tells us that in undisturbed, horizontal, sedimentary rock layers... the oldest rock layer is on the bottom and the youngest on is on the top.

Extrusions and Intrusions

* Extrusions are igneous rock that has made it to the surface and cooled.

* Intrusions are igneous rock that is trapped in the rock layers.

Clues from faults!

Law of crosscutting relationships.

Anything disturbing the rock layers, like faults, are always younger than what they are disturbing.

Multiple Choice

Which layer is the youngest and what law tells us this?

• A is the youngest. Superposition.

• D is the youngest.

  Superpositon

• C is the youngest.

  Law of crosscutting.

• B is the youngest.

  Superposition

Multiple Choice

Which feature is the youngest? Which law tells you this?

• E is the youngest.

  Superposition

• A is the youngest.

  Superposition

• E is the youngest.

  Law of Crosscutting

• D is the youngest.

  Intrusions.

Index fossils

They are usefull because they tell the relative ages of the rock layers in which they occur.

How can rock layers change?

Gaps in the geologic record and folding can change the position in which rock layers appear.

Multiple Choice

When rock layers are missing or just weren't deposited this makes an...

• unconformity

• fold

• older rock

Lesson 3 Radioactive Dating

What is radioactive decay?

What is radioactive dating?

What is radioactive decay?

This is when a particle is unstable and release energy and other particles to slowly transform into a stable element.

Half-life

this is the time it takes for 1/2 of a radioactive sample to decay away.

This time is different for every type of element.

What is radioactive dating?

This is a form of absolute dating.

In radioactive dating, scientists first determine the amount of radiation left in a rock. Then they compare that amount with the amount of stable element in the rock. They use this information and the half-life of the element to calculate the age of rock.

Multiple Choice

If a sample is 50% parent isotope and 50% daughter isotope, how many half-lives have went by?

• 1

• 2

• 3

• 4

Lesson 5 Early Earth

How did Earth form?

Earth takes shape...

Scientists think that Earth began as a ball of dust, rock, and ice in space. Gravity pulled this mass together.

The age of the Earth.

4.6 billion years old

This age is determined from using absolute dating methods on moon rocks and meteorites.

Multiple Choice

What is the age of the Earth and Moon?

• 45.365 billion years

• 123 million years.

• 4.6 Billion years

• 121 million days

The differentiation of Earth's layers.

This occured early on in Earth's formation as impacts and radioactive decay heated up the early Earth making it completely molten.

The Early Atmosphere

Was composed of mainly Helium and Hydrogen. It was ripped away by solar winds and the next atmosphere was built by volcanic eruptions and meteorite impacts. It was composed of water vapor, carbon dioxide, and nitrogen.

The Early Oceans

At first the Earth was too hot for water to remain a liquid. After it cooled, it started to rain and formed the first oceans.

The Continents

It took less than 500 million years for the first continents to start forming.

Early Organisms

Early life was single-celled. We have stromatolites that are the fossil remains of cyanobacteria that are around 3.5 billion years old.

Multiple Select

What gases were most likely in Earth's first atmosphere?

• Hydrogen

• Helium

• Oxygen

• Xenon

Multiple Choice

How long did it take for continents to start forming?

• 1.2 billion years

• Less than 500 million years.

• about 10 minutes

• There have never been continents... this is a simulation

Multiple Choice

What is the name of the process that separated Earth into layers?

• layering

• mixing

• differentiation

• interactive layering.

Poll

Is there anything you'd like me to explain better?

• Yes - if you choose "yes" click which topic.

• No

• Early Earth

• Fossils

• Relative & absolute dating