,TESTBANK FOR Biology Exploring the Diversity of
Life, 5th Edition by Peter Russell
Notes
1- The file is chapter after chapter.
2- We have shown you few pages sample.
3- The file contains all Appendix and Excel sheet
if it exists.
4- We have all what you need, we make update
at every time. There are many new editions
waiting you.
5- If you think you purchased the wrong file You
can contact us at every time, we can replace it
with true one.
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,Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
1. What are scientists using the NASA rover Perseverance to search for on Mars?
a. ancient microbial life
b. fossilized stromatolites
c. sedimentary strata
d. water in Jezero Crater
ANSWER: a
2. Which of the following would you take into account if you wanted to define viruses?
a. They are between the biotic and abiotic worlds.
b. They are able to live outside a host organism.
c. They are able to synthesize their own proteins.
d. They are able to remain unchanged.
ANSWER: a
3. Which of the following describes the order of emergence of various organisms on Earth?
a. land plants, first prokaryotes, animals, first eukaryotes, humans
b. first prokaryotes, first eukaryotes, animals, land plants, humans
c. animals, first prokaryotes, first eukaryotes, land plants, humans
d. humans, animals, land plants, first eukaryotes, first prokaryotes
ANSWER: b
4. How old is Earth?
a. about 4.6 million years old
b. about 1 billion years old
c. about 3.6 billion years old
d. about 4.6 billion years old
ANSWER: d
5. The presence of which of these factors is the most important requirement in order for life to
emerge?
a. liquid water
b. air
c. soil
d. sunlight
ANSWER: a
6. In the 1920s, Aleksandr Oparin and John Haldane each made independent proposals about the
formation of life on Earth. What did they say about essential organic molecules?
a. that these could not have been made in the absence of life in the conditions on
primordial Earth
b. that these could have been made in the presence of life in the conditions on primordial
Earth
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Chapter 1 - Defining Life and Its Origins
c. that these could have been made in the absence of life in the conditions on primordial
Earth
d. that these could have been made in the absence of life in the conditions on modern
Earth
ANSWER: c
7. Aleksandr Oparin and John Haldane postulated that the early atmosphere was a reducing
atmosphere. What does this postulation imply?
a. The atmospheric molecules contained the maximum possible number of protons that
can be easily donated in reactions that lead to synthesis of complex molecules.
b. The atmospheric molecules contained the minimum possible number of electrons that
can be easily donated in reactions that lead to synthesis of complex molecules.
c. The atmospheric molecules contained the maximum possible number of protons that
can be easily accepted in reactions that lead to synthesis of complex molecules.
d. The atmospheric molecules contained the maximum possible number of electrons that
can be easily donated in reactions that lead to synthesis of complex molecules.
ANSWER: d
8. What is the importance of the Miller–Urey experiment?
a. It showed that molecules crucial to life could be produced biotically.
b. It showed that molecules crucial to life could be produced abiotically.
c. It showed that molecules not crucial to life could be produced biotically.
d. It showed that molecules not crucial to life could be produced abiotically.
ANSWER: b
9. If an electrode is analogous to the Miller–Urey experiment, which of the following is
analogous to primordial Earth?
a. water vapour
b. a strongly reducing atmosphere
c. lightning
d. a primeval sea
ANSWER: c
10. If a condenser is analogous to the Miller–Urey experiment, which of the following is
analogous to primordial Earth?
a. a primeval sea
b. water vapour
c. cold temperature
d. lightning
ANSWER: c
11. If a warmed flask of water is analogous to the Miller–Urey experiment, which of the
following is analogous to primordial Earth?
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Chapter 1 - Defining Life and Its Origins
a. a strongly reducing atmosphere
b. lightning
c. a primeval sea
d. water vapour
ANSWER: c
12. Which of the following is NOT a reason that selection favoured DNA over RNA?
a. RNA is less chemically stable than DNA and degrades more readily.
b. The doubled-stranded nature of DNA means that mutations found on one strand are easy to
repair using information from the other strand.
c. Replacement of the base uracil in RNA with thymine in DNA means that mutations in DNA
containing uracil are easily recognized and repaired.
d. Compared to DNA, RNA is very slow to be transcribed into ribozymes necessary for catalysis
of proteins used in gene expression.
ANSWER: d
13. Which of the following contribute to evolutionary change over time?
a. changes in RNA
b. changes in DNA
c. changes in proteins
d. changes in cells
ANSWER: b
14. Which of the following is NOT one of the three key properties of cell evolution to be
considered when explaining an all-encompassing model for the origin of life?
a. All cells must develop a cell wall for stability and structure, and to protect them from harmful
microbes.
b. Cells must be able to take in energy and use it to carry out necessary functions.
c. Cells must have replicable information storage mechanisms that can be shared with other
cells.
d. Processes within the cell must occur within defined compartments separate from the outside
environment.
ANSWER: a
15. What is the flow of information that the central dogma refers to?
a. DNA RNA protein
b. DNA protein RNA
c. RNA protein DNA
d. RNA DNA protein
ANSWER: a
16. Which property of RNA makes some RNA molecules able to act as catalysts?
a. They are single-stranded molecules that can fold into very specific shapes.
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Chapter 1 - Defining Life and Its Origins
b. They are single-stranded molecules that cannot fold into very specific shapes.
c. They are double-stranded molecules.
d. They are double-stranded molecules that can fold into very specific shapes.
ANSWER: a
17. Why was ATP a primary molecule in connecting energy-releasing and energy-requiring
reactions in early cells?
a. because it was the only molecule available to transfer energy
b. because of its versatility and efficiency in transferring energy
c. because of its structure
d. because of its attraction to energy
ANSWER: b
18. What is the most surprising feature of the tree of life?
a. It has a single branch.
b. It has many branches.
c. It has many starting points.
d. It has a single starting point.
ANSWER: d
19. What does LUCA stand for?
a. last undiscovered common ancestor
b. least unified common ancestor
c. last universal common ancestor
d. last undated common ancestor
ANSWER: c
20. Where did the oxygen that has accumulated in the atmosphere come from?
a. hydrothermal vents
b. as a by-product of oxygenic photosynthesis
c. a farther atmosphere
d. oceans
ANSWER: b
21. Which of the following processes did the first oxygen molecules come from?
a. aerobic respiration
b. anaerobic respiration
c. the oxidization of water
d. the reduction of water
ANSWER: c
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Chapter 1 - Defining Life and Its Origins
22. Which statement best describes the importance of banded iron formations?
a. The rust layers in them serve as evidence for the presence of rocks on early Earth.
b. The rust layers in them serve as evidence for the presence of iron on early Earth.
c. The rust layers in them serve as evidence for the fall of atmospheric oxygen on early
Earth.
d. The rust layers in them serve as evidence for the rise of atmospheric oxygen on early
Earth.
ANSWER: d
23. What is the name of the process by which mitochondria and chloroplasts probably evolved?
a. endocytosis
b. endosymbiosis
c. exocytosis
d. exosymbiosis
ANSWER: b
24. Which of these statements does NOT describe eukaryotic cells?
a. Their cytoplasm consists of the cytosol and organelles.
b. They possess a selectively permeable membrane.
c. Their genetic material is localized in the cytoplasm.
d. Their DNA is organized into chromosomes.
ANSWER: c
25. What does a cell of prokaryotic type lack that differentiates it from a cell of eukaryotic type?
a. a plasma membrane
b. a nucleus
c. DNA
d. chromosomes
ANSWER: b
26. Which statement characterizes mitochondria and chloroplasts?
a. All proteins required for mitochondrial or chloroplast function are encoded by genes
that are found in the nucleus.
b. Both mitochondria and chloroplasts contain genetic material.
c. Ninety-five percent of the proteins required for mitochondrial or chloroplast function
are encoded by genes that are found in the nucleus.
d. Neither mitochondria nor chloroplasts contain genetic material.
ANSWER: b
27. What is indicated by the fact that NOT all eukaryotic cells contain both mitochondria and
chloroplasts?
a. Endosymbiosis did not occur at all.
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Chapter 1 - Defining Life and Its Origins
b. Endosymbiosis occurred only in the evolution of mitochondria.
c. Endosymbiosis did not occur in stages.
d. Endosymbiosis occurred in stages.
ANSWER: d
28. What are the major membrane components in a eukaryotic cell?
a. the nuclear envelope, the endoplasmic reticulum, and chloroplasts
b. the nuclear envelope, the endoplasmic reticulum, and mitochondria
c. the nuclear envelope, the endoplasmic reticulum, and the Golgi complex
d. the nuclear envelope, mitochondria, and chloroplasts
ANSWER: c
29. Which of the following is a benefit of eukaryotic cells being able to generate large amounts
of energy?
a. Cells could become less complex.
b. Cells need fewer proteins.
c. Cells no longer require a nucleus.
d. Cells could become larger.
ANSWER: d
30. What is a key trait of a multicellular organism?
a. A division of labour exists among the organism’s cells.
b. All the organism’s cells have the same function.
c. The organism has many cells.
d. All the organism’s cells are similar in shape.
ANSWER: a
31. Which of these statements best describes the fossil record?
a. It helps us to understand soft-bodied organisms from the past.
b. It has all been discovered by now.
c. It is an invaluable resource to understand the past.
d. It represents all organisms that once lived on Earth.
ANSWER: c
32. Earth is approximately 4.6 million years old.
ANSWER: False - Billion
33. The early atmosphere, as proposed by Aleksandr Oparin and John Haldane, was an oxidizing
atmosphere.
ANSWER: False - Reducing
34. Important molecules that were present in the reducing atmosphere of primordial Earth were
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,Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
oxygen (O2), hydrogen (H2), and methane (CH3).
ANSWER: False - ammonia
35. Today’s atmosphere is an oxidizing atmosphere. The presence of oxygen allows complex
molecules to be formed because oxygen is a strong oxidizing molecule.
ANSWER: False - prevents complex molecules from being
36. The energy for the synthesis of organic molecules on primordial Earth came from lightning
and intense UV radiation.
ANSWER: True
37. The energy for the synthesis of organic molecules on primordial Earth came from lightning
only.
ANSWER: False - The Sun, volcanoes, and the inner planet’s heat
38. The Miller–Urey experiment was the first experiment to demonstrate the biotic formation of
molecules critical to life.
ANSWER: False - Abiotic
39. Scientists believe that hydrothermal vents could have produced a lot more organic material
than generated by the Miller–Urey experiments.
ANSWER: True
40. Ribozymes are biological catalysts that are proteins.
ANSWER: False - Enzymes
41. The first cells were probably aerobic heterotrophs.
ANSWER: False - anaerobic
42. When it comes to the tree of life, findings indicate that there are only two primary domains.
a. True
b. False
ANSWER: True
43. The evolution of multicellularity meant that cells no longer needed to be complex.
ANSWER: False - Simple
44. Endosymbiosis means that eukaryotic cells evolved from ingested prokaryotic cells.
ANSWER: True
45. Fossils form in sedimentary rocks, where there is a lot of oxygen present.
ANSWER: False - no oxygen
46. Explain why the characteristics of life are emergent.
ANSWER: Each characteristic of life reflects a remarkable complexity resulting from a hierarchy
of interactions that begins with atoms and progresses through molecules to
macromolecules and cells. Depending upon the organism, this hierarchy may continue
upward in complexity and include organelles, tissues, and organs. The seven
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, Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
properties of life are a result of emergent properties because they come about, or
emerged, from many simpler interactions that, in themselves, do not have the
properties found at the higher levels.
47. One of the seven emergent properties of life is that organisms exhibit homeostasis. Explain
this emergent property.
ANSWER: Organisms are able to regulate their internal environment such that conditions remain
relatively constant. This ability enables organisms to be distinct from their
environment.
48. Explain the seven characteristics shared by all life forms.
ANSWER: (1) Display order (All forms of life are arranged in a highly ordered manner, with the
cell being the fundamental unit of life.); (2) Harness and utilize energy (All forms of
life acquire energy from the environment and use it to maintain their highly ordered
state.); (3) Reproduce (All organisms have the ability to make more of their own
kind.); (4) Respond to stimuli (Organisms can make adjustments to their structure,
function, and behaviour, in response to changes to the external environment.); (5)
Exhibit homeostasis (Organisms are able to regulate their internal environment such
that conditions remain relatively constant.); (6) Grow and develop (All organisms
increase their size by increasing the size and/or number of cells. Many organisms also
change over time.); (7) Evolve (Populations of living organisms change over the
course of generations to become better adapted to their environment.)
49. What does the fact that seven attributes are shared by all life on Earth suggest?
ANSWER: It suggests that all present-day organisms descended from a common ancestor.
50. Briefly describe the conditions on primordial Earth and why they were important for the first
life to be created.
ANSWER: Early Earth was bombarded by rocks from the still-forming solar system. On Earth
itself, extensive volcanic and seismic activities were present. The atmosphere on Earth
was gaseous and dusty, with abundant water vapour as well as large quantities of
hydrogen sulfide, carbon dioxide, ammonia, and methane. It is from these basic
building blocks that the molecules essential to the formation of life are thought to
have formed.
51. Describe and explain the Miller–Urey experiment.
ANSWER: A warmed flask of water simulated the primeval sea. The strongly reducing
atmosphere in the system consisted of hydrogen, methane, ammonia, and water
vapour (no free oxygen). Electrodes mimicked lightning. A condenser cooled the
atmosphere, causing rain, which together with dissolved compounds formed a liquid
Cooled water containing organic molecules was collected and sampled. A variety of
organic molecules (amino acids and complex oily hydrocarbons) were found in the
sample.
52. What was the importance of clay on early Earth?
ANSWER: Polymerization in the aqueous environment of primordial Earth could not have been
possible, because the polymers would have been quickly broken down. However, clay
is layered and as such readily absorbs ions and organic molecules, promoting
interaction and assembly reactions. Clay also stores potential energy for reactions to
Copyright Cengage Learning. Powered by Cognero. Page 8
Life, 5th Edition by Peter Russell
Notes
1- The file is chapter after chapter.
2- We have shown you few pages sample.
3- The file contains all Appendix and Excel sheet
if it exists.
4- We have all what you need, we make update
at every time. There are many new editions
waiting you.
5- If you think you purchased the wrong file You
can contact us at every time, we can replace it
with true one.
Our email:
,Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
1. What are scientists using the NASA rover Perseverance to search for on Mars?
a. ancient microbial life
b. fossilized stromatolites
c. sedimentary strata
d. water in Jezero Crater
ANSWER: a
2. Which of the following would you take into account if you wanted to define viruses?
a. They are between the biotic and abiotic worlds.
b. They are able to live outside a host organism.
c. They are able to synthesize their own proteins.
d. They are able to remain unchanged.
ANSWER: a
3. Which of the following describes the order of emergence of various organisms on Earth?
a. land plants, first prokaryotes, animals, first eukaryotes, humans
b. first prokaryotes, first eukaryotes, animals, land plants, humans
c. animals, first prokaryotes, first eukaryotes, land plants, humans
d. humans, animals, land plants, first eukaryotes, first prokaryotes
ANSWER: b
4. How old is Earth?
a. about 4.6 million years old
b. about 1 billion years old
c. about 3.6 billion years old
d. about 4.6 billion years old
ANSWER: d
5. The presence of which of these factors is the most important requirement in order for life to
emerge?
a. liquid water
b. air
c. soil
d. sunlight
ANSWER: a
6. In the 1920s, Aleksandr Oparin and John Haldane each made independent proposals about the
formation of life on Earth. What did they say about essential organic molecules?
a. that these could not have been made in the absence of life in the conditions on
primordial Earth
b. that these could have been made in the presence of life in the conditions on primordial
Earth
Copyright Cengage Learning. Powered by Cognero. Page 1
,Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
c. that these could have been made in the absence of life in the conditions on primordial
Earth
d. that these could have been made in the absence of life in the conditions on modern
Earth
ANSWER: c
7. Aleksandr Oparin and John Haldane postulated that the early atmosphere was a reducing
atmosphere. What does this postulation imply?
a. The atmospheric molecules contained the maximum possible number of protons that
can be easily donated in reactions that lead to synthesis of complex molecules.
b. The atmospheric molecules contained the minimum possible number of electrons that
can be easily donated in reactions that lead to synthesis of complex molecules.
c. The atmospheric molecules contained the maximum possible number of protons that
can be easily accepted in reactions that lead to synthesis of complex molecules.
d. The atmospheric molecules contained the maximum possible number of electrons that
can be easily donated in reactions that lead to synthesis of complex molecules.
ANSWER: d
8. What is the importance of the Miller–Urey experiment?
a. It showed that molecules crucial to life could be produced biotically.
b. It showed that molecules crucial to life could be produced abiotically.
c. It showed that molecules not crucial to life could be produced biotically.
d. It showed that molecules not crucial to life could be produced abiotically.
ANSWER: b
9. If an electrode is analogous to the Miller–Urey experiment, which of the following is
analogous to primordial Earth?
a. water vapour
b. a strongly reducing atmosphere
c. lightning
d. a primeval sea
ANSWER: c
10. If a condenser is analogous to the Miller–Urey experiment, which of the following is
analogous to primordial Earth?
a. a primeval sea
b. water vapour
c. cold temperature
d. lightning
ANSWER: c
11. If a warmed flask of water is analogous to the Miller–Urey experiment, which of the
following is analogous to primordial Earth?
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Chapter 1 - Defining Life and Its Origins
a. a strongly reducing atmosphere
b. lightning
c. a primeval sea
d. water vapour
ANSWER: c
12. Which of the following is NOT a reason that selection favoured DNA over RNA?
a. RNA is less chemically stable than DNA and degrades more readily.
b. The doubled-stranded nature of DNA means that mutations found on one strand are easy to
repair using information from the other strand.
c. Replacement of the base uracil in RNA with thymine in DNA means that mutations in DNA
containing uracil are easily recognized and repaired.
d. Compared to DNA, RNA is very slow to be transcribed into ribozymes necessary for catalysis
of proteins used in gene expression.
ANSWER: d
13. Which of the following contribute to evolutionary change over time?
a. changes in RNA
b. changes in DNA
c. changes in proteins
d. changes in cells
ANSWER: b
14. Which of the following is NOT one of the three key properties of cell evolution to be
considered when explaining an all-encompassing model for the origin of life?
a. All cells must develop a cell wall for stability and structure, and to protect them from harmful
microbes.
b. Cells must be able to take in energy and use it to carry out necessary functions.
c. Cells must have replicable information storage mechanisms that can be shared with other
cells.
d. Processes within the cell must occur within defined compartments separate from the outside
environment.
ANSWER: a
15. What is the flow of information that the central dogma refers to?
a. DNA RNA protein
b. DNA protein RNA
c. RNA protein DNA
d. RNA DNA protein
ANSWER: a
16. Which property of RNA makes some RNA molecules able to act as catalysts?
a. They are single-stranded molecules that can fold into very specific shapes.
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,Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
b. They are single-stranded molecules that cannot fold into very specific shapes.
c. They are double-stranded molecules.
d. They are double-stranded molecules that can fold into very specific shapes.
ANSWER: a
17. Why was ATP a primary molecule in connecting energy-releasing and energy-requiring
reactions in early cells?
a. because it was the only molecule available to transfer energy
b. because of its versatility and efficiency in transferring energy
c. because of its structure
d. because of its attraction to energy
ANSWER: b
18. What is the most surprising feature of the tree of life?
a. It has a single branch.
b. It has many branches.
c. It has many starting points.
d. It has a single starting point.
ANSWER: d
19. What does LUCA stand for?
a. last undiscovered common ancestor
b. least unified common ancestor
c. last universal common ancestor
d. last undated common ancestor
ANSWER: c
20. Where did the oxygen that has accumulated in the atmosphere come from?
a. hydrothermal vents
b. as a by-product of oxygenic photosynthesis
c. a farther atmosphere
d. oceans
ANSWER: b
21. Which of the following processes did the first oxygen molecules come from?
a. aerobic respiration
b. anaerobic respiration
c. the oxidization of water
d. the reduction of water
ANSWER: c
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Chapter 1 - Defining Life and Its Origins
22. Which statement best describes the importance of banded iron formations?
a. The rust layers in them serve as evidence for the presence of rocks on early Earth.
b. The rust layers in them serve as evidence for the presence of iron on early Earth.
c. The rust layers in them serve as evidence for the fall of atmospheric oxygen on early
Earth.
d. The rust layers in them serve as evidence for the rise of atmospheric oxygen on early
Earth.
ANSWER: d
23. What is the name of the process by which mitochondria and chloroplasts probably evolved?
a. endocytosis
b. endosymbiosis
c. exocytosis
d. exosymbiosis
ANSWER: b
24. Which of these statements does NOT describe eukaryotic cells?
a. Their cytoplasm consists of the cytosol and organelles.
b. They possess a selectively permeable membrane.
c. Their genetic material is localized in the cytoplasm.
d. Their DNA is organized into chromosomes.
ANSWER: c
25. What does a cell of prokaryotic type lack that differentiates it from a cell of eukaryotic type?
a. a plasma membrane
b. a nucleus
c. DNA
d. chromosomes
ANSWER: b
26. Which statement characterizes mitochondria and chloroplasts?
a. All proteins required for mitochondrial or chloroplast function are encoded by genes
that are found in the nucleus.
b. Both mitochondria and chloroplasts contain genetic material.
c. Ninety-five percent of the proteins required for mitochondrial or chloroplast function
are encoded by genes that are found in the nucleus.
d. Neither mitochondria nor chloroplasts contain genetic material.
ANSWER: b
27. What is indicated by the fact that NOT all eukaryotic cells contain both mitochondria and
chloroplasts?
a. Endosymbiosis did not occur at all.
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Chapter 1 - Defining Life and Its Origins
b. Endosymbiosis occurred only in the evolution of mitochondria.
c. Endosymbiosis did not occur in stages.
d. Endosymbiosis occurred in stages.
ANSWER: d
28. What are the major membrane components in a eukaryotic cell?
a. the nuclear envelope, the endoplasmic reticulum, and chloroplasts
b. the nuclear envelope, the endoplasmic reticulum, and mitochondria
c. the nuclear envelope, the endoplasmic reticulum, and the Golgi complex
d. the nuclear envelope, mitochondria, and chloroplasts
ANSWER: c
29. Which of the following is a benefit of eukaryotic cells being able to generate large amounts
of energy?
a. Cells could become less complex.
b. Cells need fewer proteins.
c. Cells no longer require a nucleus.
d. Cells could become larger.
ANSWER: d
30. What is a key trait of a multicellular organism?
a. A division of labour exists among the organism’s cells.
b. All the organism’s cells have the same function.
c. The organism has many cells.
d. All the organism’s cells are similar in shape.
ANSWER: a
31. Which of these statements best describes the fossil record?
a. It helps us to understand soft-bodied organisms from the past.
b. It has all been discovered by now.
c. It is an invaluable resource to understand the past.
d. It represents all organisms that once lived on Earth.
ANSWER: c
32. Earth is approximately 4.6 million years old.
ANSWER: False - Billion
33. The early atmosphere, as proposed by Aleksandr Oparin and John Haldane, was an oxidizing
atmosphere.
ANSWER: False - Reducing
34. Important molecules that were present in the reducing atmosphere of primordial Earth were
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,Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
oxygen (O2), hydrogen (H2), and methane (CH3).
ANSWER: False - ammonia
35. Today’s atmosphere is an oxidizing atmosphere. The presence of oxygen allows complex
molecules to be formed because oxygen is a strong oxidizing molecule.
ANSWER: False - prevents complex molecules from being
36. The energy for the synthesis of organic molecules on primordial Earth came from lightning
and intense UV radiation.
ANSWER: True
37. The energy for the synthesis of organic molecules on primordial Earth came from lightning
only.
ANSWER: False - The Sun, volcanoes, and the inner planet’s heat
38. The Miller–Urey experiment was the first experiment to demonstrate the biotic formation of
molecules critical to life.
ANSWER: False - Abiotic
39. Scientists believe that hydrothermal vents could have produced a lot more organic material
than generated by the Miller–Urey experiments.
ANSWER: True
40. Ribozymes are biological catalysts that are proteins.
ANSWER: False - Enzymes
41. The first cells were probably aerobic heterotrophs.
ANSWER: False - anaerobic
42. When it comes to the tree of life, findings indicate that there are only two primary domains.
a. True
b. False
ANSWER: True
43. The evolution of multicellularity meant that cells no longer needed to be complex.
ANSWER: False - Simple
44. Endosymbiosis means that eukaryotic cells evolved from ingested prokaryotic cells.
ANSWER: True
45. Fossils form in sedimentary rocks, where there is a lot of oxygen present.
ANSWER: False - no oxygen
46. Explain why the characteristics of life are emergent.
ANSWER: Each characteristic of life reflects a remarkable complexity resulting from a hierarchy
of interactions that begins with atoms and progresses through molecules to
macromolecules and cells. Depending upon the organism, this hierarchy may continue
upward in complexity and include organelles, tissues, and organs. The seven
Copyright Cengage Learning. Powered by Cognero. Page 7
, Name: Class: Date:
Chapter 1 - Defining Life and Its Origins
properties of life are a result of emergent properties because they come about, or
emerged, from many simpler interactions that, in themselves, do not have the
properties found at the higher levels.
47. One of the seven emergent properties of life is that organisms exhibit homeostasis. Explain
this emergent property.
ANSWER: Organisms are able to regulate their internal environment such that conditions remain
relatively constant. This ability enables organisms to be distinct from their
environment.
48. Explain the seven characteristics shared by all life forms.
ANSWER: (1) Display order (All forms of life are arranged in a highly ordered manner, with the
cell being the fundamental unit of life.); (2) Harness and utilize energy (All forms of
life acquire energy from the environment and use it to maintain their highly ordered
state.); (3) Reproduce (All organisms have the ability to make more of their own
kind.); (4) Respond to stimuli (Organisms can make adjustments to their structure,
function, and behaviour, in response to changes to the external environment.); (5)
Exhibit homeostasis (Organisms are able to regulate their internal environment such
that conditions remain relatively constant.); (6) Grow and develop (All organisms
increase their size by increasing the size and/or number of cells. Many organisms also
change over time.); (7) Evolve (Populations of living organisms change over the
course of generations to become better adapted to their environment.)
49. What does the fact that seven attributes are shared by all life on Earth suggest?
ANSWER: It suggests that all present-day organisms descended from a common ancestor.
50. Briefly describe the conditions on primordial Earth and why they were important for the first
life to be created.
ANSWER: Early Earth was bombarded by rocks from the still-forming solar system. On Earth
itself, extensive volcanic and seismic activities were present. The atmosphere on Earth
was gaseous and dusty, with abundant water vapour as well as large quantities of
hydrogen sulfide, carbon dioxide, ammonia, and methane. It is from these basic
building blocks that the molecules essential to the formation of life are thought to
have formed.
51. Describe and explain the Miller–Urey experiment.
ANSWER: A warmed flask of water simulated the primeval sea. The strongly reducing
atmosphere in the system consisted of hydrogen, methane, ammonia, and water
vapour (no free oxygen). Electrodes mimicked lightning. A condenser cooled the
atmosphere, causing rain, which together with dissolved compounds formed a liquid
Cooled water containing organic molecules was collected and sampled. A variety of
organic molecules (amino acids and complex oily hydrocarbons) were found in the
sample.
52. What was the importance of clay on early Earth?
ANSWER: Polymerization in the aqueous environment of primordial Earth could not have been
possible, because the polymers would have been quickly broken down. However, clay
is layered and as such readily absorbs ions and organic molecules, promoting
interaction and assembly reactions. Clay also stores potential energy for reactions to
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