Geological Time

How long ago did the Earth form?

• 4,600 years ago

• 460,000 years ago

• 4.6 billion years ago

According to the text, how many mass extinctions have we had in Earth's history?

• 3

• 1

• 0

• 5

Age of mammals

• Precambrian

• Paleozoic

• Mesozoic

• Cenozoic

According to the Law of ______________, sedimentary rock

layers are laid down on top of each other. In

order for the rock layer to form, a layer of rock must have existed below it.

• Superposition

• Horizontality

• Unconformities

• Uniformitarianism

Which layer is the oldest?

• A

• B

• C

• D

What part of an organism is most likely to become a fossil?

• heart

• bones

• skin

The length of time required for half of the radioactive atoms in a sample to decay is its...

• era
• age
• half-life
• eon

Match the following

• Hard parts of an organism are buried in sediment & decay leaving a hollow imprint

• Trace Fossils

• Sediment fills all empty spaces creating a solid copy of the dead organism

• Mold Fossils

• provide evidence of the ACTIVITIES of organisms such as a footprint

• Cast Fossils

What are fossils that are abundant, easily recognizable, short lived, and widespread called?

• Preserved fossils

• Index fossils

• Imprints

• Radioactive dating

Over millions of years, animals have evolved in shape and size. The nautiloid is one of those animals. Which of the following is a descendant of the nautiloid found during the Cambrian period?

• bryozoans

• nautilus

• trilobites

• arthropods