History of Earth and Fossils

Which of these choices is the best definition of absolute dating?

• determining the age of a rock layer by studying the fossils present

• finding the age of an object compared to other objects

• measuring the age of an object in years using any method

• determining the amount of a radioactive isotope in an object

What is the approximate age of Earth?

• 4.6 billion years

• 4.6 million years

• 46,000 years

• 4600 years

Which of these statements describes a key characteristic of index fossils?

• They existed in a unique location.

• They are present in very small numbers.

• They existed for a short span of time.

• They are similar to other fossils.

Which method could be used to determine the age of samples of rock from the moon?

• radiocarbon dating

• index fossil dating

• sedimentary rock dating

• uranium-lead dating

What geologic change is shown in the figure?

• erosion

• abrasion

• deposition

• volcanism

How was the fossil of this insect formed?

• by being petrified

• by being trapped in asphalt

• by being trapped in hardened tree sap (amber)

• by being buried in sediment that slowly decays

Sometimes a fossil is formed as a result of the movement of an organism in soft sediment. What type of fossil is this called?

• bone fossil

• trace fossil

• frozen fossil

• petrified fossil

Trace fossils are much more common than body fossils. Which of the following best explains why trace fossils are more common?

• Trace fossils take less time to form.

• Body fossils require soft sediment to form.

• An organism is more likely to live on soft sediment where trace fossils form.

• A single animal can leave thousands of traces in its lifetime but will leave only one body when it dies.

What could you conclude if you discovered this fossil on top of a mountain?

• This organism is now extinct.

• This trace fossil is older than the mountaintop.

• The mountaintop is made of metamorphic rock.

• The rocks on this mountaintop were once at the bottom of an ocean.

Which of the following is the best conclusion that you could make from this fossil discovery?

• The climate was cooler than it is at present.

• The climate was warmer than it is at present.

• The climate has not changed since the fossil formed.

• The climate will continue to get colder in the near future.