Change over Time

Change over Time

Open Ended

How old is Earth ?

Open Ended

How do you believe Earth was formed ?

Objectives :

1. How old is Earth ?

2. How does the Acretion theory proposes the formation of Earth ?

3. What is the Geological Timescale?

4. How does the Geological Time Scale help us to better understand the changes that takes place over time ?

5. Based on the Geological Time Scale , how has life on Earth evolved ?

   
   

Theories of Earth's Formation

1. Big Bang Theory

2. Tidal Theory

3. Binary Star Hypothesis

4. Planetesimal  Hypothesis
   

You will watch a short video showing Earth's formation based on

CORE ACRETION THEORY

Multiple Choice

How many years ago did the Earth form?

• about 4.5 billion years

• ago 100,000 years ago

• 1 million years ago

• 2000 years ago

Earths formation

• 4.5 billion years a go a swirling cloud of matter called Nebula came together and became compacted to form the sun

• It was comprised of Gas and Dust

Multiple Choice

What is Nebula ?

• a cloud of gas and dust

• Water and Dust

• Water and gas

• Water and Nickel

• Left over gases of dust and metals orbitited the sun

• Earth and other planets developed from the left over

• Planets start to form when gravity pull clumps of metal and other solid together

• Lumps grew increasing in mass and gravity

• As they got bigger they attract more clumps .

• This is called accretion

• Accretion impact creates a lot of heat in forming the planets

• Earth was so hot it has molten rock and metals

• Heavier rocks such as iron and nickel sink to the middle

• Lighter rock material rise to the surface and cools to become the crust

• 
  

• 
  

Multiple Choice

What process causes small rocks to build up and form larger rocks and then finally a planet?

• Rock formation

• gravity

• accretion

Multiple Choice

What sank to the middle?

• Lighter rock and gases

• Heavier rock and metal

• Lighter rock and metal

Multiple Choice

What happened to the lighter rock that floated to the surface?

• It cooled off and formed the crust..

• It heated up and formed the mantle

• It cooled off and formed the inner core.

• The crust is the thinnest and the outermost part of Earth

• Next is the mantle which is hot the top part is molten , like lava

• Deeper down pressure keep the mantle more solid and rigid

• The core is extremely hot and made up of iron and nickel

• The core is formed due to accretion

• Outer core is molten

• Inner core is solid

• The solid core moves in the liquid core

• The movement creates a magnetic field around the whole planet

• Helps direction and shields Earth from dangerous rays of the sun

Multiple Choice

What process created the core?

• accumulation

• accretion

• rock cycle

Multiple Choice

What is formed as a result of the movement of the solid inner core in the outer molten core ?

• Earthquake

• Magnetic Field

• Hurricane

• Solar Flare

Open Ended

After Earth was initially formed do you believe it could have sustained Life, Why or Why Not ?

• Earth was too Hot

• There was no Oxygen

• Its atmosphere had gas that would not support life

• While there was water vapor there were no oceans , rivers etc.

Open Ended

Since Earth was theorized to have been formed 4.5 billion years ago , How long ago do you believe life appeared ?

Open Ended

How do you believe life on Earth has changed over time ?

Earth’ History is captured in what is known as the

Geological Time Scale

GEOLOGICAL TIME SCALE

• Shows the different lifeform that existed

• Shows the Changes they went through

• Shows events that results in the change of Earths feature and its Life-forms

Geological Time Scale

• Eons : Largest

• Eras

• Periods

• Epochs

Multiple Choice

Which division is the largest ?

• Epoch

• Era

• Eons

• Periods

We will focus on Eras

• Precambrian : Earliest

• Paleozoic: Older or ancient

• Mesozoic : Middle

• Cenozoic : Most recent

Pre-Cambrian Era

• It began with the creation of the Earth around 4.6 billion years ago.

• There was the formation of the Sun and light

Events in Precambrian

• The creation of the Earth and ocean

• The creation of the atmosphere

• The creation of life, simple life forms such as bacteria and simple algae. 

• The rise of simple organisms such as jellyfish and sea worms

Multiple Choice

Which of the following statement is not true of the Precambrian Era?

• the creation of the atmosphere

• Early land plants included simple mosses, ferns

• the creation of the oceans

• the creation of life.

Paleozoic Era

• Pangea was formed

• Early invertebrates trilobites and brachiopods

• Early vertebrate fish

• Arachnids and insects

• Later came the first amphibians. 

• Near the era’s end the reptiles became dominant

Paleozoic Era cont'd

• Early land plants included simple mosses, ferns, and then cone-bearing plants. 

• By the end of the era, seed plants were common. 

• The mass extinction that ended the era

• most marine invertebrates as well as amphibians disappeared

• Pangea split

Multiple Choice

Which of the following is not true of the Paleozoic era?

• Pangea was formed

• Dinosaurs ruled

• Mass Extinction of invertebrates

• The emergence of arachnids and insects

Mesozoic Era

• Reptiles were the dominant animals of this era, including the various dinosaurs. 

• Small mammals and birds also appeared

• Toward the end of the era, flowering plants appeared, and the kinds of mammals increased.

• The mass extinction that ended the era caused the dinosaurs to become extinct.

Multiple Choice

Reptiles and Dinosaurs were not common during this Era

• True

• False

Cenozoic Era

• New mammals appeared while others became extinct.   

• The diversity of life forms increased.

• Flowering plants became most common.

• Humans are also part of the most recent period of this era

• Ice Age

Multiple Choice

Which era was the Ice age ?

• Precambrian

• Cenozoic

• Paleozoic

• Mesozoic

Open Ended

How has Earth Changed from the Precambrian to the Cenozoic time in which we now live ? ( Features, lifeform etc)

Multiple Choice

Which order is correct ?

• Precambrian, Mesozoic, Paleozoic, Cenozoic

• Precambrian, Paleozoic, Mesozoic, Cenozoic

• Precambrian, Paleozoic, Mesozoic, Cenozoic

• Precambrian, Cenozoic Paleozoic, Mesozoic