Earth's History OST Practice

Tectonic stresses can cause rocks to break. The feature produced when broken blocks of rock slide against each other is called a fault. Which rock exposure displays evidence of faulting?

• A
• B
• C
• D

A river has cut a channel deep into the earth and exposed several layers of undisturbed sedimentary rock as shown in the cross section. Which layer is the oldest?

• Layer 1 because it is closest to the surface
• Layer 2 because it has the greatest thickness
• Layer 3 because it has the most fossils
• Layer 4 because it is on the bottom

Scientists record the types of fossils found in different layers of sedimentary rock in one location. They observe that lower layers have more species than upper layers. Which piece of evidence would help scientists understand the change in species numbers?

• rate of sediment deposition
• presence of cross-cutting volcanic intrusions
• environmental conditions at the time of deposition
• type of parent rock where the sediment weathered

The diagram below represents a desert ecosystem. Fossils 1 and 2 represent fossil evidence found in the rock layers as indicated. Arrows between organisms indicate direction of energy flow. From the fossil evidence, what conclusion can be made about the history of the environment that is new desert?

• It was always a desert.
• It is slowly turning into a forest.
• It was a forest and became a lake and then a desert.
• It was a lake and became a forest and then a desert.

Which statement regarding the relative ages of rocks and events is accurate?

• Intrusive rock is older than the surrounding rock layers.
• A fold is older than the oldest rock layer it contains.
• Faults are younger than the youngest rock layer they cut through.
• Rock layers that have been overturned are oldest from the base to the surface.

The evolution of photosynthetic organisms about 2.5 billion years ago led to

• an increase in the ultraviolet radiation reaching Earth's surface

• an increase in oxygen in the atmosphere

• the Precambrian Explosion

• the first mass extinction

The geologic time scale is a record of

• the thickness of sedimentary layers

• the rate of fossil formation

• the life forms and geologic events in Earth's history

• the time since the evolution of dinosaurs

The Paleozoic, Mesozoic, and Cenozoic are divisions in the geologic time scale called

• centuries

• periods

• layers

• eras

Radioactive dating enables geologists to determine

• the age of atoms in a rock

• the half-life of a fossil organism

• the relative ages of rocks

• the absolute ages of rocks

A type of organism that no longer exists on Earth is said to be

• fossilized

• sedimentary

• extinct

• petrified