Question 1

At the end of which of the following periods did oxygen concentrations decrease from about 30 percent to 15 percent?

Accepted Answer

A)  Cambrian 
B)  Cretaceous 
C)  Permian 
D)  Devonian 
E)  None of the above 
A)  Cambrian 
B)  Cretaceous 
C)  Permian 
D)  Devonian 
E)  None of the above

Question 2

The concentration of oxygen in the Earth's atmosphere

Accepted Answer

A)  has increased steadily through time. 
B)  has decreased steadily through time. 
C)  has been both higher and lower in the past than at present. 
D)  was lower during most of the Permian than at present. 
E)  was at its highest levels in the Cambrian. 
A)  has increased steadily through time. 
B)  has decreased steadily through time. 
C)  has been both higher and lower in the past than at present. 
D)  was lower during most of the Permian than at present. 
E)  was at its highest levels in the Cambrian.

Question 3

14C can be used to determine the ages of fossil organisms because

Accepted Answer

A)  all organisms contain many carbon compounds. 
B)  14C has a regular rate of decay to 14N. 
C)  the ratio of 14C to 12C in living organisms is always the same as that in the atmosphere. 
D)  the production of new 14C in the atmosphere just balances the natural radioactive decay of 14C. 
E)  All of the above 
A)  all organisms contain many carbon compounds. 
B)  14C has a regular rate of decay to 14N. 
C)  the ratio of 14C to 12C in living organisms is always the same as that in the atmosphere. 
D)  the production of new 14C in the atmosphere just balances the natural radioactive decay of 14C. 
E)  All of the above

Question 4

Over geologic time, the concentration of O2 in Earth's atmosphere has increased. During the _______ period, the O2 concentration decreased significantly and resulted in _______.

Accepted Answer

A)  Devonian; rapid evolution of lineages 
B)  Carboniferous; mass extinctions 
C)  Permian; mass extinctions 
D)  Cretaceous; rapid evolution of lineages 
E)  Cretaceous; mass extinctions 
A)  Devonian; rapid evolution of lineages 
B)  Carboniferous; mass extinctions 
C)  Permian; mass extinctions 
D)  Cretaceous; rapid evolution of lineages 
E)  Cretaceous; mass extinctions

Question 5

A fossil of a rodent, suspected to be a billion years old, is discovered in South America. How might the age of the fossil be determined?

Accepted Answer

A)  14C dating of the fossil 
B)  From the strata the fossil was found in 
C)  Comparison to other fossil organisms in the same strata 
D)  40K dating of igneous rocks near the fossil 
E)  Both a and d 
A)  14C dating of the fossil 
B)  From the strata the fossil was found in 
C)  Comparison to other fossil organisms in the same strata 
D)  40K dating of igneous rocks near the fossil 
E)  Both a and d

Question 6

Paleontologists have subdivided the Cenozoic era into epochs because

Accepted Answer

A)  Homo sapiens evolved at the start of the Cenozoic. 
B)  the continents had achieved their present positions. 
C)  the number of species stopped increasing at this time. 
D)  our knowledge of the evolutionary events of the Cenozoic is more extensive than for other eras. 
E)  starting with the Cenozoic, the fossil record is no longer a necessary source of information about evolutionary relationships. 
A)  Homo sapiens evolved at the start of the Cenozoic. 
B)  the continents had achieved their present positions. 
C)  the number of species stopped increasing at this time. 
D)  our knowledge of the evolutionary events of the Cenozoic is more extensive than for other eras. 
E)  starting with the Cenozoic, the fossil record is no longer a necessary source of information about evolutionary relationships.

Question 7

Oxygen-generating cyanobacteria liberated enough O2 to open the door to _______ reactions in metabolic pathways leading to the evolution of larger _______ cells.

Accepted Answer

A)  reduction; prokaryotic 
B)  reduction; archaea 
C)  oxidation; prokaryotic 
D)  oxidation; eukaryotic 
E)  None of the above 
A)  reduction; prokaryotic 
B)  reduction; archaea 
C)  oxidation; prokaryotic 
D)  oxidation; eukaryotic 
E)  None of the above

Question 8

One billion years ago, Earth was in the _______ era.

Accepted Answer

The answer of One billion years ago, Earth was in...

Question 9

Evidence for continental drift might include

Accepted Answer

A)  the good fit of the coastlines of western Africa and eastern South America. 
B)  that similar fossils are found in places distant from each other. 
C)  that similar rock formations are found in Appalachia and Antarctica. 
D)  the mass extinctions of marine organisms. 
E)  All of the above 
A)  the good fit of the coastlines of western Africa and eastern South America. 
B)  that similar fossils are found in places distant from each other. 
C)  that similar rock formations are found in Appalachia and Antarctica. 
D)  the mass extinctions of marine organisms. 
E)  All of the above

Question 10

Based on the experiment in which Drosophila flies were raised at a higher than normal oxygen concentration, which of the following statements is most likely true?

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. 
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 11

Which of the following experienced major radiations during the Cenozoic?

Accepted Answer

A)  Non-avian dinosaurs 
B)  Mammals 
C)  Flowering plants 
D)  Both a and b 
E)  Both b and c 
A)  Non-avian dinosaurs 
B)  Mammals 
C)  Flowering plants 
D)  Both a and b 
E)  Both b and c

Question 12

During which geological period did Pangaea became fully divided and distinctive assemblages of plants and animals begin to arise on different continents?

Accepted Answer

A)  Cambrian 
B)  Tertiary 
C)  Devonian 
D)  Permian 
E)  Jurassic 
A)  Cambrian 
B)  Tertiary 
C)  Devonian 
D)  Permian 
E)  Jurassic

Question 13

Which of the following statements about the Mesozoic is true?

Accepted Answer

A)  Atmospheric levels of oxygen fell during the Mesozoic. 
B)  The same groups of animals that were dominant during the Permian were also dominant throughout the Mesozoic. 
C)  Pangaea came together during the Mesozoic. 
D)  All of the above 
E)  None of the above 
A)  Atmospheric levels of oxygen fell during the Mesozoic. 
B)  The same groups of animals that were dominant during the Permian were also dominant throughout the Mesozoic. 
C)  Pangaea came together during the Mesozoic. 
D)  All of the above 
E)  None of the above

Question 14

Rocklike structures formed by the oxygen-generating cyanobacteria are known as

Accepted Answer

A)  strata. 
B)  stromatolites. 
C)  igneous. 
D)  lithospheric. 
E)  rift valleys. 
A)  strata. 
B)  stromatolites. 
C)  igneous. 
D)  lithospheric. 
E)  rift valleys.

Question 15

Which of the following gases has substantially increased in concentration in the last 200 years?

Accepted Answer

A)  Oxygen 
B)  Carbon dioxide 
C)  Nitrogen 
D)  Argon 
E)  Hydrogen 
A)  Oxygen 
B)  Carbon dioxide 
C)  Nitrogen 
D)  Argon 
E)  Hydrogen

Question 16

The first period of the Mesozoic, the _______, saw the breakup of the supercontinent _______.

Accepted Answer

The answer of The first period of the Mesozoic, the...

Question 17

Which of the following statements about radioisotope dating is false?

Accepted Answer

A)  The isotopes in sedimentary rocks contain reliable information about the dates of their formation. 
B)  Igneous rocks are formed when molten material cools. 
C)  The decay of potassium-40 to argon-40 has been used to date most of the ancient events in the evolution of life. 
D)  Paleomagnetic dating relates the ages of rocks to patterns in Earth's magnetism. 
E)  All of the above are true; none is false. 
A)  The isotopes in sedimentary rocks contain reliable information about the dates of their formation. 
B)  Igneous rocks are formed when molten material cools. 
C)  The decay of potassium-40 to argon-40 has been used to date most of the ancient events in the evolution of life. 
D)  Paleomagnetic dating relates the ages of rocks to patterns in Earth's magnetism. 
E)  All of the above are true; none is false.

Question 18

Heat generated in Earth's core results in _______ currents in the magma. This process pushes the _______ plates along with the land masses on top of them.

Accepted Answer

convection

Question 19

Oxygen (O2) in Earth's atmosphere was

Accepted Answer

A)  generated by photosynthetic cyanobacteria by oxidation of water. 
B)  generated abiotically. 
C)  generated by nonphotosynthetic bacteria. 
D)  present in high amounts before the origin of life. 
E)  present in low amounts when larger eukaryotes evolved. 
A)  generated by photosynthetic cyanobacteria by oxidation of water. 
B)  generated abiotically. 
C)  generated by nonphotosynthetic bacteria. 
D)  present in high amounts before the origin of life. 
E)  present in low amounts when larger eukaryotes evolved.

Question 20

Use the following to answer questions:
Refer to the diagram below, showing the decay of a radioactive substance.  
-Assuming this substance started decaying 280,000 years ago, and 4 mg of it remains, there was roughly how much of the original substance?

Accepted Answer

A)  1 mg 
B)  2 mg 
C)  8 mg 
D)  16 mg 
E)  64 mg 
A)  1 mg 
B)  2 mg 
C)  8 mg 
D)  16 mg 
E)  64 mg

Exam 25: The History of Life on Earth

At the end of which of the following periods did oxygen concentrations decrease from about 30 percent to 15 percent?

The concentration of oxygen in the Earth's atmosphere

14C can be used to determine the ages of fossil organisms because

Over geologic time, the concentration of O2 in Earth's atmosphere has increased. During the _______ period, the O2 concentration decreased significantly and resulted in _______.

A fossil of a rodent, suspected to be a billion years old, is discovered in South America. How might the age of the fossil be determined?

Paleontologists have subdivided the Cenozoic era into epochs because

Oxygen-generating cyanobacteria liberated enough O2 to open the door to _______ reactions in metabolic pathways leading to the evolution of larger _______ cells.

One billion years ago, Earth was in the _______ era.

Evidence for continental drift might include

Based on the experiment in which Drosophila flies were raised at a higher than normal oxygen concentration, which of the following statements is most likely true?

Which of the following experienced major radiations during the Cenozoic?

During which geological period did Pangaea became fully divided and distinctive assemblages of plants and animals begin to arise on different continents?

Which of the following statements about the Mesozoic is true?

Rocklike structures formed by the oxygen-generating cyanobacteria are known as

Which of the following gases has substantially increased in concentration in the last 200 years?

The first period of the Mesozoic, the _______, saw the breakup of the supercontinent _______.

Which of the following statements about radioisotope dating is false?

Heat generated in Earth's core results in _______ currents in the magma. This process pushes the _______ plates along with the land masses on top of them.

Oxygen (O2) in Earth's atmosphere was

Use the following to answer questions: Refer to the diagram below, showing the decay of a radioactive substance. -Assuming this substance started decaying 280,000 years ago, and 4 mg of it remains, there was roughly how much of the original substance?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Signaling and Communication

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinent Dna and Biotechnology

Differential Gene Expression in Development

Development and Evolutionary Change

Evidence and Mechanisms of Evolution

Reconstructing and Using Phylogenies

Species and Their Formation

Evolution of Genes and Genomes

Bacteria and Archaea: the Prokaryotic Domains

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

Fungi: Recyclers, Pathogens, Parasites, and Plant Partners

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Function

Musculoskeletal Systems

Gas Exchange in Animals

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen

Animal Behavior

Ecology and the Distribution of Life

Population Ecology

Species Interaction and Coevolution

Community Ecology

Ecosystems and Global Ecology

Conservation Biology

Filters

¹⁴C can be used to determine the ages of fossil organisms because

Over geologic time, the concentration of O₂ in Earth's atmosphere has increased. During the _ period, the O₂ concentration decreased significantly and resulted in _.

Oxygen-generating cyanobacteria liberated enough O₂ to open the door to _ reactions in metabolic pathways leading to the evolution of larger _ cells.

The first period of the Mesozoic, the _, saw the breakup of the supercontinent _.

Heat generated in Earth's core results in _ currents in the magma. This process pushes the _ plates along with the land masses on top of them.

Oxygen (O₂) in Earth's atmosphere was