Question 1

The principles of stratigraphy are often used to determine the relative ages of fossils.Which statement is an important assumption of this method?

Accepted Answer

A)  The decay rate of a radioactive substance is constant. 
B)  The decay rates of different radioactive substances are different. 
C)  The sedimentary rocks in which the fossils have been found have been disturbed. 
D)  The sedimentary rocks in which the fossils have been found have not been disturbed. 
E)  The fossils are in igneous rocks.

Question 2

In undisturbed sedimentary rock, strata from which period would be immediately below rocks from the Ordovician?

Accepted Answer

A)  Devonian 
B)  Cretaceous 
C)  Jurassic 
D)  Silurian 
E)  Cambrian

Question 3

Suppose the half-life of a radioactive isotope is 900 years.Of the total amount of that element assimilated by living organisms into their tissues, 0.002 percent consists of the radioactive isotope.If you were to find a skeleton of an organism that had 0.0005 percent of the element as the radioactive isotope, it would be estimated to be _______ years old.

Accepted Answer

The answer of Suppose the half-life of a radioactive isotope...

Question 4

A fossil of a marine crab, suspected to be 500 million years old, is discovered in South America.Which of the following is the most accurate way of determining the age of the fossil?

Accepted Answer

A)  14C dating of the fossil 
B)  Dating the strata the fossil was found in 
C)  Comparing the fossil to other fossil organisms in the same strata 
D)  Radiometric dating of igneous rocks near the fossil using 40K 
E)  Use of a molecular clock

Question 5

During the _______ period, fishes diversified and evolved jaws; club mosses, horsetails, and tree ferns became common; the earliest insects and terrestrial vertebrates arose; and there was a mass extinction at the end of the period that may have been caused by meteorites.

Accepted Answer

A)  Precambrian 
B)  Devonian 
C)  Triassic 
D)  Silurian 
E)  Quaternary

Question 6

The time interval spanning four billion years across three eons is the

Accepted Answer

A)  Phanerozoic. 
B)  Proterozoic. 
C)  Archaean. 
D)  Hadean. 
E)  Precambrian.

Question 7

Which statement about igneous rocks is true?

Accepted Answer

A)  They are formed via the accumulation of grains at the bottoms of rivers and other bodies of water. 
B)  They are only found in ancient oceans. 
C)  They are more reliable in radiometric dating than sedimentary rock. 
D)  The best way to discover their age is through carbon-14 dating. 
E)  They are commonly known as amber.

Question 8

Refer to the figure.  The diversification of multicellular lineages associated with the Cambrian explosion lasted about _______ percent of the span of time during which life existed before the Cambrian explosion.

Accepted Answer

A)  0.2 
B)  0.5 
C)  2 
D)  5 
E)  10

Question 9

The experiment in which Drosophila flies were raised at a higher-than-normal oxygen concentration led to which of the following conclusions?

Accepted Answer

A)  Fly body size is constrained because there are not enough alleles that increase body size. 
B)  Fly body size is constrained because alleles that increase body size are selected against at normal oxygen levels. 
C)  At normal oxygen concentration levels, fly body size is under strong directional selection. 
D)  Fly body size would likely increase if flies were raised at lower-than-normal oxygen concentrations. 
E)  Increased oxygen levels appear to have little effect on fly body size, even after many generations.

Question 10

Humans evolved during the _______ era.

Accepted Answer

The answer of Humans evolved during the _______ era....

Question 11

Much of the _______ we now use for energy consists largely of the remains of plants that grew in swamps during the Carboniferous period.

Accepted Answer

The answer of Much of the _______ we now use...

Question 12

The current geological period, the Quaternary is divided into two epochs: the _______ and the Holocene.

Accepted Answer

The answer of The current geological period, the Quaternary is...

Question 13

What is the most likely factor constraining body size in Drosophila at current levels of oxygen?

Accepted Answer

A)  Mutation 
B)  Genetic drift 
C)  Stabilizing selection 
D)  Directional selection 
E)  Disruptive selection

Question 14

Insects are _______ represented in the fossil record because they_______.

Accepted Answer

A)  well; die in oxygen-rich areas 
B)  well; are numerous 
C)  poorly; are numerous 
D)  poorly; have an exoskeleton 
E)  poorly; are small

Question 15

As a result of continental drift, the continent of _______ (which was attached to Antarctica when most other continents were part of Gondwana and Laurasia) has its own unique fauna compared to the rest of the modern terrestrial world.

Accepted Answer

The answer of As a result of continental drift, the...

Question 16

Refer to the figure to interpret the relative contribution of various risk factors toward the possible local extinction of a species.  Which of the following would be most likely to cause the local extinction of a population of kelp with 100 individuals?

Accepted Answer

A)  Random changes in birth or death rates 
B)  Low genetic variation associated with small populations 
C)  A change in temperature, water quality, or sunlight availability 
D)  Disadvantages associated with low population density 
E)  A complex interaction between demographic variation and genetic effects

Question 17

Which sample would not be appropriate for dating by means of radioactive potassium?

Accepted Answer

A)  A Homo erectus skeleton thought be around 800,000 years old 
B)  An igneous intrusion into the sediments of the Cretaceous sea where they are now exposed on land 
C)  An igneous intrusion from a 250-million-year-old volcano eruption associated with the Permian mass extinction 
D)  An igneous intrusion into the sediments of the Cambrian sea where they are now exposed on land 
E)  Stromatolites containing 3-billion-year-old bacterial mats

Question 18

The mass extinction at the end of the Ordovician period was probably caused by

Accepted Answer

A)  the collision of Earth with a large meteorite. 
B)  massive volcanic eruptions. 
C)  massive glaciation on the southern continents and associated climate changes. 
D)  the coming together of the continents to form Pangaea. 
E)  changes in Earth's orbit.

Question 19

Which statement about the principles of stratigraphy is true?

Accepted Answer

A)  They were first established by Darwin. 
B)  Application of these principles alone allows scientists to determine absolute ages of fossils. 
C)  Older rocks are found closer to the surface than younger rocks. 
D)  Older rocks have stronger magnetic properties than younger rocks. 
E)  Stratigraphy can tell us a lot about fossils embedded in sedimentary rock.

Question 20

In undisturbed strata of sedimentary rock, the oldest rocks

Accepted Answer

A)  lie at the top. 
B)  lie at the bottom. 
C)  are in the middle. 
D)  are distributed among the strata of younger rocks. 
E)  None of the above

Exam 24: The History of Life on Earth