History of Earth Unit Test

Why is it important for geologists to use both relative and absolute ages to determine the age of rocks?

• Scientists want to learn about the age of rocks.
• Scientists need only one way to determine the age of rocks.
• Scientists can tell the age of rocks using the law of superposition.
• Scientists may not be able to determine the absolute age of some rocks.

Sara was studying the methods scientists use to determine the ages of the rock layers. She was particularly interested in the use of index fossils. After looking at the picture, she noticed that the rock layers at Location 4 differed from the other three locations. What likely occurred at Location 4?

• Layer B isn't shown due to the absence of index fossils.
• Layer B eroded away and layers C and D were deposited on top of layer A at a later time.
• Location 4 held index fossils similar to the other locations.
• Location 4 had heavy erosion and soon a layer of rock will be deposited on top of it.

What is the purpose of the geologic time scale?

• to organize and sequence events by eras and periods in the different divisions of time and to serve as a timeline
• to show the evolution of life forms and to model how those life forms behaved and what they ate
• to organize and sequence events in the history of Earth and to serve as a model for a vast amount of time covered
• to determine the relative ages of rocks and when and how they formed to create a timeline of their development

Choose the TWO phrases that best characterize Precambrian time.

• a time of few fossils
• a time of great evolutionary change
• a time with multiple periods in it
• a time that covers 88 percent of Earth's history

Why do so few fossils from the Precambrian time on the geologic timeline exist?

• Single-celled organisms don't form fossils.
• The single-celled organisms died out before any fossils were formed.
• The time was so long ago and most fossils may have been destroyed.
• The time was long ago and the fossils are so deeply buried they haven't been discovered.

Studying rocks allows scientists to understand and organize the history of Earth. Some scientists study ______________ , which are the preserved traces or remains of living things.

• minerals
• plants
• skeletons
• fossils

What type of rocks are fossils found in?

• igneous
• metamorphic
• sedimentary
• mineralized rock

How do layers of sedimentary rocks help geologists identify the age of rocks?

• The oldest layers are on the bottom.
• The youngest layers are on the bottom.
• The oldest layers might have fossils in them.
• The youngest layers are the most compacted.

The earliest life forms that developed on Earth were single-celled and lived in the oceans. Choose the TWO statements about the changes of developing life through Earth’s long history that are true.

• Organisms didn't change very much over time.
• Organisms grew increasingly complex.
• Many organisms grew simpler.
• Many organisms died out over time.

Choose 2 pieces of evidence that scientists use to develop the geologic time scale.

• radioactive dating
• eras and periods
• worldwide rock layes and index fossil