Earth's History Unit 9 Exam

A 10 million year old fossil of an urchin was discovered at a stream site near Charleston. The fossil was likely formed when a tsunami buried the urchin under many layers of mud and silt which compacted the urchin nearly flat. Over time, these layers formed sedimentary rock and left an organic impression. 
How would the fossil be classified?

• Mold fossil
• Petrified fossil
• Preserved fossil
• Trace fossil

Which length of geologic time is associated with the appearance of humans?

• Cambrian Period
• Cenozoic Era
• Mesozoic Era
• Precambrian Era

Which statement about extinction in Earth's history is correct?

• Animals only started becoming extinct over the past 5 million years when they were hunted by humans
• Earth has warmed steadily throughout its history and slowly causing species to become extinct. 
• Extinction events are always negative because they eliminate all species of life on Earth when they occur. 
• Natural extinctions have occurred throughout Earth's geologic history from a variety of causes. 

How do scientists use ice cores?

• to determine the age of preserved fossils
• to determine past earthquake activity
• to determine past climate conditions
• to determine the age of deposited sediment

The diagram above represents a section of undisturbed layers of sedimentary rock in North Carolina and shows the location of fossils of several closely related species. Which statement below is accurate about species A, B, and C?

• Species B is more abundant than species C.
• Species C existed before species B.
• Species A and B are genetically identical.
• Species B evolved from species A.

Which rock layer is the youngest?
NOTE: Layer 6 is cutting through layers 1, 4, and 2 ONLY

• Layer 1
• Layer 6
• Layer 5
• Layer 3

Which of the following is true about the rock layer above?

• Layer 6 is older than layers 1, 2, and 4 because the igneous rock is cutting through these layers.
• Layer 3 is older than layer 6 because igneous intrusions are always youngest.
• Layer 6 is older than layer 5 because it does not cut through 5.
• The fossil in layer 3 is younger than layer 6 because lava came before fossils.

In general, the law of superposition states that in an undisturbed sequence of sedimentary rocks, each layer is:

• about the same age.
• older than the one above it.
• older than the one below it.
• thicker than the one above it.

Which best describes a fossil that helps determine the relative age of a rock layer?

• Trace fossil
• Index fossil
• Radioactive fossil
• Unconformity fossil

Which statement best describes the Law of Superposition?

• Each sedimentary layer of rock represents 1,000 years of Earth’s age, much like the rings of a tree.
• In undisturbed layers of sedimentary rock, the upper rock layers are older than the lower rock layers
• In undisturbed layers of sedimentary rock, the lowest layers contain the older rocks.
• Rocks that form near volcanoes are older than surrounding rocks.