PaleontologyStudy Guide Answers

Please take a sheet of paper and label it “extra info”

Older than 50,000 = Uranium lead Method

Younger than 50,000 = Carbon-14 Method

#1 How do scientists date material older than 50,000 years? Younger than 50,000?

Sedimentary

#2 What type of rock are most fossils found in?

Where dry land was once under water Example: shark tooth in Georgia How the environment has changed

#3 What can fossils tell us about an area’s history?

Younger rocks are on the top.

Older rocks are on the bottom.

Layers must be undisturbed

#4 What does the law of superposition state?

Mineral Replacement

Usually happens to wood or bones

#5 What is petrification?

PrecambrianPaleozoicMesozoic Cenozoic

*Currently we are in the cenozoic

#6 List the Geological era’s in order from earliest to most recent

Hint: Think

Alphabet

Approximately 4.6

BILLION Years

#7 How old is the Eath’s History date back to?

Index fossils are used to determine relative age.

Index fossils are widespread geographically, are limited to a short span of geologic time, and occur in large numbers.

It’s an actual FOSSIL

Trace fossils are indirect evidence of

prehistoric life. Can tell us about

the activity of an animal

Examples: Footprints, trails, poop

#8 What’s the difference between index and trace fossils

Sequence Age COMPARED to other rocks Older or younger NO NUMBER Uses: Index fossils Law of superposition Law of original horizontality

#9 What is relative age and how do you find the relative age?

Most precise Gives an actual age Puts a number to the age. This is why

we use it! Uses: Radioactive decay Carbon 14 or uranium lead Half-life

#10 What is absolute age?

Geological changes such as dry areas that were once under water

Organisms have become more complex and how they have evolved

How the environment looked in the past How rock layers in different areas match

up How environment/animals have

changed The age of certain layers of rocks

#11 What can scientists learn from studying fossils?

Uniformitarianism – the idea that the same geologic processes shaping the Earth today

have been at work throughout Earth’s history

#12 What is uniformitarianism? What is original horizontality

The principle of original horizontality means that layers of sediment are generally deposited in

a horizontal position.

Eons-eras-periods-epochsBroken up so it’s more manageable

Eras are broken by a huge climate change or mass extinction

#13 How is the geologic time scale broken down

DryAnd

Freezing

Temperatures

#14 What slows down the decaying process

Climate changeMaybe:

Pange breaking apart Or

Asteroid causing a huge dust cloud

#15 What do scientists think caused the extinction of dinosaurs?

Incomplete

Most organisms don’t become fossils

#16 Are fossil records complete or incomplete? Why?

Flood, mudslide, volcanic ash, earthquake, etc.

Can lead to the formation of fossils

#17 What is a catastrophic event?

Mold: cavity where an organism once was (cakepan)

Cast: sediment that fills the cavity (batter)

#18 cast vs. mold

Needs to have a rapid burial and have the hard parts of

the organism be preserved!!!

#19. How are fossils formed?

They’ve become more complex

One cell to humans

#20. what do fossil records tell us about organisms