SCIENCE LESSON 1 (ROCKS AND FOSSILS)

Is the preserved remains, impression, or trace of an organism that lived million years ago

Fossils

Are the preserved remains of organisms

Body Fossil

Evidence of an organisms activity

Trace Fossils

A hollow impression left after the original decays

Mold Fossils

Formed when minerals fill a mold and create or copy of the original organism

Cast Fossils

How old is the earth?

454 Billion of years old

Examples of Fossil

Bones

Teeth

Sheels

Leaves

Foot Prints

Burrows

What are the type of fossils?

Body Fossils

Trace Fossils

Mold Fossils

Cast Fossils

Carbon Films

Preserved Remains

Thin carbon outline left an organisms is compressed

Carbon Films

The Carbon Films is commonly found in

Leaves

Insects

Organisms preserved in amber, ice, tar and dry environments

Preserved Remains

Examples of Body Fossils

Bones

Teeth

Shells

Leaves

Examples of Trace Fossils

Foot Prints

Burrows

Trails

Nets

Fossilazation is a _____ ____ that usually takes a million of years

Slow Process

Fossilization is a slow process that usually takes a _____

Million of Years

The general sequence of fossilization

1. An organism dies

2. The remains are buried by sediements

3. Layers of sediment accumulate and harden into rocks

4. Mineral replace the organism tissue

5. Erosion or weathering exposes the fossil at Earth surface

Conditions Needed for Fossil Formation

Rapid Burial

Hard Body Parts

Low oxygen

Mineral-rich water

Little disturbnce after burial

Why are Fossil Important??

-Study the evolution of organisms

-Identify extinct species

-Understand ancient environments

-Determinte the relative ages of rock layers

-Reconstruct Earth's history

What are the two main dating methods?

Relative Dating

Absolute Dating

Two dating methods

Relative Dating

Absolute Dating

The two methods use by the scientists to identify rock’s age

Relative Dating

Absolute Dating

Determine whether one rock is older or younger than another. It does not provide the exact age

Relative Dating

What dating method that determine whether one rock is older or younger than another?

Relative Dating

What dating methods that does not provide the exact age of rocks?

Relative Dating

Principles of Relative Dating

Law of Superposition

Original Horizontality

Cross-cutting Relationship

Fossil Succesion

Is an undisturbed sequence of sedimenting rocks

Law of Superposition

Is an undisturbed sequence of sedimenting rocks. The oldest rock is at the bottom while the youngest rock is at the top

Law of Superposition

The oldest rock is at the bottom while the youngest rock is at the top

Law of Superposition

Sediments ars originally deposited in horizontal layers. If layers become foldes or tilted, the change occured after deposition

Original Horizontality

A fault, crack, or igneous intrusion that cuts across layers is younger than the rock it cuts

Cross-cutting Relationship

Rock layers containing the same fossils, are generally the same relative age, even if they are found in different places

Fossil Succesion

Fossil occur in a _____ ___

Predictable Order

Does fossil occur in a predictable order?

YES

Does fossil occur in a predictable order or in a unpredictable order?

Predictable Order

According to the Principle Of Relative. Where is the old rocks located?

Bottom

According to the Law Of Superposition. Where is the old rocks located?

Bottom

Where is the old rocks located?

Bottom

It is said that the oldest (old) rocks are located in the bottom and the youngest (younger) rocs are located in the top. It is accoring to the

Law of Superposition

The rocks that cuts across layer is it younger or older than the rock it cut?

Younger

If rock layers contain the same fossils. What does it mean interms of its age?

They have the same relative age

Rock layers containing the same fossils, are generally have the same different age, even if they are found in different places

FALSE

Even if the fossil are found in different places (rock layers) is it still that the rock layers have the same relative age?

YES

Advantages of Relative Dating

Simple and inexpensive

Useful for comparying rock layer

Helps determine the sequence of geological event

Useful in studying Earth's History

Limitation of Relative Dating

Cannot determine the exact age

Disturbed rock layers may affect accuracy

Depends on the arrangement of rock layers

Determines the actual numerical age of rocks or fossils. Unlike relative dating, it provides aged in years, million of years, and billion of years

Absolute Dating

It determines the actual numerical age of rocks or fossils. Unlike relative dating, it provides aged in years, million of years, and billion of years. What is that method of dating?

Absolute Dating

It determines the actual numerical age of rocks or fossils. What is that method of dating?

Absolute Dating

It determines the actual numerical age of rocks or fossils.

Absolute Dating

Absolute dating is based on

Radiactive Decay

Are unstable atons that naturally change into different substancesover time

Radiactive Elements

Is the amount of time required for half of the radiactive atoms in a sample to dacay

Half-Life

Is the amount of time required for half of the radiactive atoms in a sample to dacay

Example:

8 atoms - 4 atoms after one half-life

4 atoms - 2 atoms after two half-lives

2 atoms- 1 atom after three half-lives

Half Life

Each half-life reduces the number of radiaoctive atoms by half

TRUE/YES

Complete the sentence

Each half-life

Reduces the number of radiaoctive atoms by half

Common Radiometric Dating Methods

Carbon 14-Dating

Uranium Lead-Dating

Potassium-Argon Dating

What are Common Radiometric Dating Methods?

Carbon 14-Dating

Uranium Lead-Dating

Potassium-Argon Dating

It is a radiometric dating methods that used in bones, wood, plant remains, and other organic materials

Carbon-14 Dating

Used in bones, wood, plant remains, and other organic materials

Carbon-14 Dating

It is a radiometric dating methods that used in very old rocks (rocks million to billion of years old)

Uranium-Lead Dating

It is a radiometric dating methods the used in volcanic rocks

Potassium-Argon Dating

Used in very old rocks

Uranium-Lead Dating

Used in volcanic rocks

Potassium-Argon Dating

Advantages of Absolute Dating

Determines the actual age of rocks and fossils

More accurate than the relative dating

Uses predictable radioactive decay

Help scientists better understand Earth's history

Limitation of Absolute Dating

Requires specialized laboratory equipment

Can be expensive

Only works on suitable materials, containing radioactive elements

Difference between Relative Dating and Absolute Dating

Relative Dating

-determines whether rocks are older or younger

-no exact age

-uses rock layers and fossils

-simple and inexpensive

Absolute Dating

-determines the actual numerical age

-gives exact age in years

-uses radiactive elements

-more accurate but requires specialized equipment