Question 1

Why does understanding the origin of life require the collaboration of biologists, chemists, geologists, and atmospheric scientists?

Accepted Answer

Biologists provide a definition of life and an understanding of the process of evolution. Chemists provide an understanding of the reactions necessary to produce the organic molecules used by living organisms. Geologists provide an understanding of the conditions on Earth billions of years ago when life began. Atmospheric scientists provide understanding of the atmospheric conditions on Earth billions of years ago when life began. All of this information is needed to evaluate how life started.

Question 2

Why would natural selection favor reduced parasitic bacterial genomes?

Accepted Answer

A)  The parasitic lifestyle eliminates metabolism, leading to gene loss. 
B)  Parasitic bacteria are primitive and never had metabolic genes. 
C)  Parasites have reduced metabolic needs, which leads to gene loss. 
D)  Transposons have caused mutagenesis and genes have been lost. 
A)  The parasitic lifestyle eliminates metabolism, leading to gene loss. 
B)  Parasitic bacteria are primitive and never had metabolic genes. 
C)  Parasites have reduced metabolic needs, which leads to gene loss. 
D)  Transposons have caused mutagenesis and genes have been lost. C

Question 3

Current scientific estimates indicate that Earth is approximately 4.5-4.6 ________ years old and that life began on Earth approximately 3.2-3.5 ________ years ago.

Accepted Answer

A)  billion; million 
B)  million; million 
C)  billion; billion 
D)  million; billion 
A)  billion; million 
B)  million; million 
C)  billion; billion 
D)  million; billion C

Question 4

Deletion experiments of E. coli have determined the minimal set of metabolic pathways. When these pathways were compared to a closely related species, W. glossinidia, an endosymbiotic organism that obtains resources from its host, researchers found that

Accepted Answer

A)  W. glossinidia had fewer metabolic pathways. 
B)  E. coli was more specialized and had fewer metabolic pathways. 
C)  the gene sets match perfectly. 
D)  the genomes were not comparable. 
A)  W. glossinidia had fewer metabolic pathways. 
B)  E. coli was more specialized and had fewer metabolic pathways. 
C)  the gene sets match perfectly. 
D)  the genomes were not comparable.

Question 5

Sol Spiegelman and colleagues demonstrated natural selection with RNA molecules. How did they satisfy the three conditions required for natural selection?

Accepted Answer

For natural selection to occur, there mu

Question 6

How do comparative data on genes of extant species help us to make estimates of what happened before the phylogenetic event horizon?

Accepted Answer

A)  Common genes must have existed for a long time, possibly since the first life-forms. 
B)  Common functional genes imply the minimal characteristics of early cells. 
C)  If the first life-forms consisted of RNA, then current RNA-coding genes must be the ancestral genes. 
D)  The first life-forms must have been endosymbionts because most small-genome extant bacteria are endosymbionts. 
A)  Common genes must have existed for a long time, possibly since the first life-forms. 
B)  Common functional genes imply the minimal characteristics of early cells. 
C)  If the first life-forms consisted of RNA, then current RNA-coding genes must be the ancestral genes. 
D)  The first life-forms must have been endosymbionts because most small-genome extant bacteria are endosymbionts.

Question 7

The two major cell types currently known are

Accepted Answer

A)  archaea and bacteria. 
B)  archaea and prokaryotes. 
C)  prokaryotes and eukaryotes. 
D)  eukaryotes and archaea. 
A)  archaea and bacteria. 
B)  archaea and prokaryotes. 
C)  prokaryotes and eukaryotes. 
D)  eukaryotes and archaea.

Question 8

Why might the analysis of endosymbiotic bacterial genomes be misleading for understanding the minimal gene set?

Accepted Answer

A)  They are bacteria and therefore have nothing in common with LUCA. 
B)  They may have gained genes to be able to live within another organism. 
C)  They may have lost genes that would have been essential to early life-forms due to their reduced metabolic requirements. 
D)  Their genes can be disrupted by transposons. 
A)  They are bacteria and therefore have nothing in common with LUCA. 
B)  They may have gained genes to be able to live within another organism. 
C)  They may have lost genes that would have been essential to early life-forms due to their reduced metabolic requirements. 
D)  Their genes can be disrupted by transposons.

Question 9

How did the discovery of ribozymes affect our understanding of the evolution of proteins and nucleic acids?

Accepted Answer

A)  The discovery of ribozymes demonstrated that enzymes did not have to be proteins, and RNA enzymes (ribozymes) can be both information carrier and enzymatic molecule. 
B)  The discovery of ribozymes helped us understand how RNA only codes for proteins and does not act as an enzymatic molecule. This helped support the hypothesis of RNA world as an origin for living organisms on Earth. 
C)  The discovery of ribozymes verified that enzymes had to be proteins. This discovery helped to eliminate other theories about the origin of life in RNA world. 
D)  The discovery of ribozymes demonstrated definitively that ribozymes function only as an enzymatic molecule and therefore evolved before information carrier molecules. 
A)  The discovery of ribozymes demonstrated that enzymes did not have to be proteins, and RNA enzymes (ribozymes) can be both information carrier and enzymatic molecule. 
B)  The discovery of ribozymes helped us understand how RNA only codes for proteins and does not act as an enzymatic molecule. This helped support the hypothesis of RNA world as an origin for living organisms on Earth. 
C)  The discovery of ribozymes verified that enzymes had to be proteins. This discovery helped to eliminate other theories about the origin of life in RNA world. 
D)  The discovery of ribozymes demonstrated definitively that ribozymes function only as an enzymatic molecule and therefore evolved before information carrier molecules.

Question 10

Molecular mutualism is

Accepted Answer

A)  an interaction of molecules that disrupts hypercycles. 
B)  an interaction of two species to the benefit of both. 
C)  an interaction between molecules that positively impacts the replication of each. 
D)  replication of RNA by another enzyme. 
A)  an interaction of molecules that disrupts hypercycles. 
B)  an interaction of two species to the benefit of both. 
C)  an interaction between molecules that positively impacts the replication of each. 
D)  replication of RNA by another enzyme.

Question 11

Replicators A, B, C, and D become encapsulated by a membrane of fatty acids they produced. Building the membrane resulted in a great metabolic cost. The new membrane provides limited control over the new microenvironment, is fairly permeable, and frequently allows unneeded substances in while allowing newly made molecules to dissipate into the environment. Given this information, is it likely this new encapsulation will be favored by natural selection?

Accepted Answer

A)  Yes, encapsulation always confers an advantage. 
B)  Yes, the metabolic costs outweigh the benefits of microenvironment control. 
C)  No, encapsulation is beneficial but does not affect how natural selection operates. 
D)  No, encapsulation had a high metabolic cost and the membrane provides little benefit for encapsulation. 
A)  Yes, encapsulation always confers an advantage. 
B)  Yes, the metabolic costs outweigh the benefits of microenvironment control. 
C)  No, encapsulation is beneficial but does not affect how natural selection operates. 
D)  No, encapsulation had a high metabolic cost and the membrane provides little benefit for encapsulation.

Question 12

How does this figure illustrate a line of evidence supporting RNA world?

Accepted Answer

A)  This figure illustrates a cofactor that indicates catalytic and structural functions performed by RNAs. 
B)  This figure illustrates the removal of a hydroxyl group through a ribonucleotide reductase. 
C)  This figure shows the catalytic site of a ribosome that is formed entirely from RNA. 
D)  This figure illustrates one of the many essential parts of RNA present in the prebiotic environment. 
A)  This figure illustrates a cofactor that indicates catalytic and structural functions performed by RNAs. 
B)  This figure illustrates the removal of a hydroxyl group through a ribonucleotide reductase. 
C)  This figure shows the catalytic site of a ribosome that is formed entirely from RNA. 
D)  This figure illustrates one of the many essential parts of RNA present in the prebiotic environment.

Question 13

How did phospholipids confer an advantage in terms of natural selection for vesicles that had higher phospholipid content?

Accepted Answer

A)  Vesicles with higher phospholipid content could tolerate a wider range of temperatures in a warmer world. 
B)  Vesicles with higher phospholipid content were more efficient at transporting materials back and forth across the membrane. 
C)  Vesicles with higher phospholipid content tended to grow more than those with lower phospholipid content, giving higher phospholipid vesicles the ability to outcompete others. 
D)  Vesicles with higher phospholipid content were able to tolerate a more acidic environment that was typical of the prebiotic "soup" that existed at the time cells originated. 
A)  Vesicles with higher phospholipid content could tolerate a wider range of temperatures in a warmer world. 
B)  Vesicles with higher phospholipid content were more efficient at transporting materials back and forth across the membrane. 
C)  Vesicles with higher phospholipid content tended to grow more than those with lower phospholipid content, giving higher phospholipid vesicles the ability to outcompete others. 
D)  Vesicles with higher phospholipid content were able to tolerate a more acidic environment that was typical of the prebiotic "soup" that existed at the time cells originated.

Question 14

Which of the following was NOT identified as a basic function of genes included in a minimal gene set of Bacillus subtilis in Koonin's 2003 study?

Accepted Answer

A)  translation 
B)  metabolism 
C)  photosynthesis 
D)  replication and repair 
A)  translation 
B)  metabolism 
C)  photosynthesis 
D)  replication and repair

Question 15

The figure shows horizontal gene transfer and the early evolution of life. Based on this figure, order the following events from earliest to latest.   A. Mitochondrial horizontal gene transfer
B. Chloroplast horizontal gene transfer
C. Plants and algae separate from animals and fungi
D. Fungi separate from animals

Accepted Answer

The correc

Question 16

Describe the four lines of evidence supporting "RNA world."

Accepted Answer

Many present-day protein-based enzymes h

Question 17

How can both clay and ice crystals enhance chemical reactions necessary to form complex organic molecules?

Accepted Answer

A)  Both have highly reactive surfaces that help to lower the energy of activation for reactions that form complex organic molecules. 
B)  Both trap the water needed in reactions that result in organic molecules. 
C)  Both have the necessary elements to form amino acids. 
D)  Both have microscopic spaces that help to concentrate reagents, facilitating reactions involving those reagents. 
A)  Both have highly reactive surfaces that help to lower the energy of activation for reactions that form complex organic molecules. 
B)  Both trap the water needed in reactions that result in organic molecules. 
C)  Both have the necessary elements to form amino acids. 
D)  Both have microscopic spaces that help to concentrate reagents, facilitating reactions involving those reagents.

Question 18

Explain molecular mutualism and how it is applied to the hypercycle model.

Accepted Answer

A molecular mutualism occurs when two or

Question 19

Consider this figure showing horizontal gene transfer and the early evolution of life. Which of the following statements is FALSE?

Accepted Answer

A)  Bacteria have transferred genes to eukaryotes twice. 
B)  Bacteria have transferred genes to archaea many times. 
C)  Bacteria have transferred genes among themselves. 
D)  Eukaryotes have transferred genes among themselves. 
A)  Bacteria have transferred genes to eukaryotes twice. 
B)  Bacteria have transferred genes to archaea many times. 
C)  Bacteria have transferred genes among themselves. 
D)  Eukaryotes have transferred genes among themselves.

Question 20

In the hypercycle illustrated in the figure, the four components increase their own replication and also positively affect the replication of other members. How does the presence of a membrane, uniting the four components, favor the connections between the members of the hypercycle in this case compared to a set that does not have a membrane?

Accepted Answer

An increase in one of the connections he

Why does understanding the origin of life require the collaboration of biologists, chemists, geologists, and atmospheric scientists?

Why would natural selection favor reduced parasitic bacterial genomes?

Current scientific estimates indicate that Earth is approximately 4.5-4.6 years old and that life began on Earth approximately 3.2-3.5 years ago.

Deletion experiments of E. coli have determined the minimal set of metabolic pathways. When these pathways were compared to a closely related species, W. glossinidia, an endosymbiotic organism that obtains resources from its host, researchers found that

Sol Spiegelman and colleagues demonstrated natural selection with RNA molecules. How did they satisfy the three conditions required for natural selection?

How do comparative data on genes of extant species help us to make estimates of what happened before the phylogenetic event horizon?

The two major cell types currently known are

Why might the analysis of endosymbiotic bacterial genomes be misleading for understanding the minimal gene set?

How did the discovery of ribozymes affect our understanding of the evolution of proteins and nucleic acids?

Molecular mutualism is

How does this figure illustrate a line of evidence supporting RNA world?

How did phospholipids confer an advantage in terms of natural selection for vesicles that had higher phospholipid content?

Which of the following was NOT identified as a basic function of genes included in a minimal gene set of Bacillus subtilis in Koonin's 2003 study?

Describe the four lines of evidence supporting "RNA world."

How can both clay and ice crystals enhance chemical reactions necessary to form complex organic molecules?

Explain molecular mutualism and how it is applied to the hypercycle model.

Consider this figure showing horizontal gene transfer and the early evolution of life. Which of the following statements is FALSE?

An Overview of Evolutionary Biology

Early Evolutionary Ideas and Darwin S Insight

Natural Selection

Phylogeny and Evolutionary History

Inferring Phylogeny

Transmission Genetics and the Sources of Genetic Variation

The Genetics of Populations

Evolution in Finite Populations

Evolution at Multiple Loci

Genome Evolution

Major Transitions

Evolution and Development

Species and Speciation

Extinction and Evolutionary Trends

The Evolution of Sex

The Evolution of Sociality

Coevolution

Human Evolution

Evolution and Medicine

Filters

Exam 11: The Origin and Evolution of Early Life

Why does understanding the origin of life require the collaboration of biologists, chemists, geologists, and atmospheric scientists?

Why would natural selection favor reduced parasitic bacterial genomes?

Current scientific estimates indicate that Earth is approximately 4.5-4.6 ________ years old and that life began on Earth approximately 3.2-3.5 ________ years ago.

Deletion experiments of E. coli have determined the minimal set of metabolic pathways. When these pathways were compared to a closely related species, W. glossinidia, an endosymbiotic organism that obtains resources from its host, researchers found that

Sol Spiegelman and colleagues demonstrated natural selection with RNA molecules. How did they satisfy the three conditions required for natural selection?

How do comparative data on genes of extant species help us to make estimates of what happened before the phylogenetic event horizon?

The two major cell types currently known are

Why might the analysis of endosymbiotic bacterial genomes be misleading for understanding the minimal gene set?

How did the discovery of ribozymes affect our understanding of the evolution of proteins and nucleic acids?

Molecular mutualism is

How does this figure illustrate a line of evidence supporting RNA world?

How did phospholipids confer an advantage in terms of natural selection for vesicles that had higher phospholipid content?

Which of the following was NOT identified as a basic function of genes included in a minimal gene set of Bacillus subtilis in Koonin's 2003 study?

Describe the four lines of evidence supporting "RNA world."

How can both clay and ice crystals enhance chemical reactions necessary to form complex organic molecules?

Explain molecular mutualism and how it is applied to the hypercycle model.

Consider this figure showing horizontal gene transfer and the early evolution of life. Which of the following statements is FALSE?

An Overview of Evolutionary Biology

Early Evolutionary Ideas and Darwin S Insight

Natural Selection

Phylogeny and Evolutionary History

Inferring Phylogeny

Transmission Genetics and the Sources of Genetic Variation

The Genetics of Populations

Evolution in Finite Populations

Evolution at Multiple Loci

Genome Evolution

Major Transitions

Evolution and Development

Species and Speciation

Extinction and Evolutionary Trends

The Evolution of Sex

The Evolution of Sociality

Coevolution

Human Evolution

Evolution and Medicine

Filters

Current scientific estimates indicate that Earth is approximately 4.5-4.6 years old and that life began on Earth approximately 3.2-3.5 years ago.