Question 1

The relative-dating principle of __ states that fragments included in a host rock are older than the host rock.

Accepted Answer

The principle of inclusion states that fragments included in a host rock are older than the host rock. This is because the fragments must have existed first in order to be incorporated into the host rock through some sort of geological activity.

Question 2

Our ability to assign an age to geological and archaeological materials is based on our ability to measure the relative abundance of radioactive ___ and their stable decay products.

Accepted Answer

Radiometric dating relies on the measurement of isotopes of certain elements such as carbon-14, uranium-238, and potassium-40. These isotopes decay at a predictable rate over time and can be used to date materials such as rocks, fossils, and artifacts. By measuring the ratio of parent isotopes to daughter isotopes, scientists can accurately determine the age of the material.

Question 3

The Earth's largest mass extinction coincides with _____ in Siberia.

Accepted Answer

The largest mass extinction, known as the Permian-Triassic extinction, coincides with massive volcanism in Siberia, which led to significant climate change due to the release of large amounts of carbon dioxide and other greenhouse gases into the atmosphere. This event is thought to have caused the extinction of up to 96% of all marine species and 70% of terrestrial vertebrate species.

Question 4

The ___ of a radioactive material is the time it takes for a given amount of radioactive isotope to be reduced by half.

Accepted Answer

The term used to describe the time it takes for a given amount of radioactive isotope to be reduced by half is "half-life". Therefore, the correct answer is E. The other options (atomic life, atomic mass life, atomic spin life, nuclear magnetic life) are not commonly-used terms in radioactive decay and are not accurate descriptions of the half-life concept.

Question 5

The ____ is based upon the observation that fossil species succeed one another through layers in a predictable order.

Accepted Answer

The principle of faunal succession states that fossil species succeed one another through layers in a predictable order.

Question 6

When the ____ came to a close, dinosaurs became extinct.

Accepted Answer

Dinosaurs lived during the Mesozoic Era, which ended about 66 million years ago with a mass extinction event believed to have been caused by an asteroid impact.

Question 7

Isotopic dating has shown that the Precambrian took up ______% of all geologic time.

Accepted Answer

Isotopic dating has shown that the Precambrian era, which encompasses the time from the formation of the Earth about 4.6 billion years ago to the start of the Cambrian period about 541 million years ago, took up about 87% of all geologic time. This era represents the vast majority of Earth's history.

Question 8

In geology, _____ usually means determining time equivalency of rock units.

Accepted Answer

Correlation is the process of determining the time equivalency of rock units in different areas, which involves matching up fossil assemblages and other features to determine the relative ages of the rocks. Physical continuity and lateral continuity refer to the spatial relationships of rock units, while unconformity and superposition refer to the deposition and layering of rocks.

Question 9

The _____ ended with the greatest mass extinction ever to occur on Earth.

Accepted Answer

The Paleozoic Era ended with the greatest mass extinction event, known as the Permian-Triassic extinction or the Great Dying. Approximately 96% of marine species and 70% of terrestrial species went extinct during this time.

Question 10

The _____ is the principle says that the same processes and natural laws that operated in the past are those we can actually observe or infer from observation as operating at present.

Accepted Answer

The answer of The _____ is the principle says that...

Question 11

When marine geologists collects a core of undeformed ocean-floor sediment, they know that the youngest layer is on the top of the core and the oldest is at the bottom because of the principle of __.

Accepted Answer

The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer is younger than the one below it and older than the one above it. This principle applies to ocean-floor sediment as well, and therefore the youngest layer is on the top of the core and the oldest is at the bottom.

Question 12

The half-life of the carbon 14 isotope is 5730 years. If there were 4 billion atoms of C-14 in a particular organism at the time it died, how many atoms of C-14 would there be in the remains of that organism 11,460 years after it died?

Accepted Answer

The half-life of C-14 is 5730 years. After 11,460 years, which is two half-lives (5730 * 2), the number of C-14 atoms would be halved twice: 4 billion -> 2 billion -> 1 billion.

Question 13

______ denotes the vast amount of time that precedes the Paleozoic Era.

Accepted Answer

The Precambrian represents the vast amount of time before the Paleozoic Era, which includes the Archean and Proterozoic Eons. A, B, C, and E all represent later periods in geological time.

Question 14

_____ are subdivisions of eras.

Accepted Answer

Periods are subdivisions of eras in the geological time scale. Ages and epochs are subdivisions of periods. Eons are the largest subdivisions of the geological time scale, while formations are individual rock layers or units within a specific time period. Intervals are a general term for any length of time between two specific events or points.

Question 15

The Earth is approximately _____ years old.

Accepted Answer

The current scientific consensus is that the Earth is approximately 4.54 billion years old. This falls within the range of 4.5 billion to 4.6 billion years old, which is option D. Options A, B, and C are too young, and option E is too old.

Question 16

The principle of ___ states that an original sedimentary layer extends laterally until it tapers or thins at is edges.

Accepted Answer

The principle of lateral continuity states that sedimentary layers extend laterally until they thin or taper at their edges, implying that they were originally continuous over a wide area. This principle is particularly useful when analyzing the layers of sedimentary rocks exposed in outcrops or in stratigraphic records. The other answer choices are different principles of stratigraphy that refer to other aspects of rock formation and deformation, such as the relative ages of rock layers (superposition), the cutting of one geologic feature by another (cross-cutting relationships), the way sedimentary rocks are deposited (original horizontality), or the idea that the same geological processes happening now also happened in the past (actualism).

Question 17

The ___ Era began with the appearance of complex life, as indicated by fossils like trilobites.

Accepted Answer

The Paleozoic Era is characterized by the appearance of complex life, as indicated by fossils like trilobites. The other options are incorrect as the Quaternary, Cenozoic, and Mesozoic Eras are all after the Paleozoic Era, and the Precambrian refers to the time period before the appearance of complex life.

Question 18

By the principle of __, the surface feature known as the Grand Canyon is ___ than the sedimentary formations that are exposed in the side walls of the Grand Canyon.

Accepted Answer

The principle of cross-cutting relationships states that a geological feature that cuts across another feature must be younger than the feature it cuts. The Grand Canyon, being a surface feature that cuts through the sedimentary formations, is therefore younger than the formations it exposes.

Question 19

The _______ Era is the Age of Mammals.

Accepted Answer

The Cenozoic Era is also known as the Age of Mammals, which began after the extinction of dinosaurs at the end of the Mesozoic Era. The Archean and Precambrian are both much earlier geological time periods that predate the era of mammals, while the Paleozoic and Mesozoic eras are known for the rise of reptiles and dinosaurs, respectively.

Question 20

Alvarez and others proposed a hypothesis that dinosaur extinction occurred because __.

Accepted Answer

Alvarez and others proposed the hypothesis that a massive asteroid impact caused the extinction of dinosaurs. This theory is widely accepted in the scientific community.

Quiz 8: Time and Geology