Question 1

How does the Black Queen Hypothesis explain the effect of gene deletions on bacterial evolution?

Accepted Answer

The answer of How does the Black Queen Hypothesis explain...

Question 2

Construct a chart to demonstrate the molecular features of the primary domains of life.Why are there overlapping or shared molecular features between all three domains? Relate the shared and unique molecular features of each domain to early evolution,the last universal common ancestor (LUCA),and the evolution of the three domains

Accepted Answer

The answer of Construct a chart to demonstrate the molecular...

Question 3

Chemical reactions involving ________ have been proposed as energy-yielding reactions for primitive organisms.

Accepted Answer

A)  Fe, O₂, and H₂ 
B)  S, O₂, and H₂ 
C)  S, and O₂ 
D)  S, and H₂

Question 4

The earliest nucleic acid was probably a simple DNA molecule.

Accepted Answer

A) True 
 B)False

Question 5

At present there are four phyla in the domain Bacteria.

Accepted Answer

A) True 
 B)False

Question 6

Explain the strengths and limitations of using 16S rRNA for phylogenetic analyses.

Accepted Answer

The answer of Explain the strengths and limitations of using...

Question 7

It is believed that phototrophy arose approximately 3.3 billion years ago in

Accepted Answer

A)  Bacteria. 
B)  Archaea. 
C)  Eukarya. 
D)  LUCA.

Question 8

Which is NOT a characteristic of a "primitive" state of microbial evolution?

Accepted Answer

A)  hyperthermophilic 
B)  aerobic metabolism 
C)  small genome 
D)  branching near the root of the evolutionary tree of life

Question 9

DNA:DNA hybridization is a sensitive method for revealing subtle genetic differences because it measures the degree of sequence similarity between two genomes.

Accepted Answer

A) True 
 B)False

Question 10

What type of methods are used in microbial systematics? Why are multiple methods used to characterize and classify microbial species? Be sure to define the methods and describe the general strengths and weaknesses of each type.

Accepted Answer

The answer of What type of methods are used in...

Question 11

Lateral gene transfer is one plausible explanation as to why organisms in Archaea,Bacteria,and Eukarya still share so many genes among such distinct domains.

Accepted Answer

A) True 
 B)False

Question 12

Approximately 4 billion years ago Archaea and Bacteria diverged as being distinct from each other.

Accepted Answer

A) True 
 B)False

Question 13

Both deletions and insertions occur during the evolution of microbial genomes.Insertions bring in new genes that may be useful for the cell,but deletions

Accepted Answer

A)  may increase fitness of a microorganism by eliminating unneeded genes. 
B)  always result in a severe loss of fitness for the microorganism. 
C)  are uncommon because they are usually lethal. 
D)  always result in a severe loss of fitness but keep microbial genomes compact.

Question 14

Microbial species have a core genome and a pan genome.What is the difference between the two?

Accepted Answer

A)  The core genome consists of all the nucleic acid polymerases and translation enzymes, while the pan genome consists of all the biosynthetic pathways. 
B)  The core genome is the set of genes within the mitochondria, while the pan genome is the set of genes in the nucleus of a species. 
C)  The core genome is a set of genes shared by all members of a species, while the pan genome includes the core genes as well as genes that are not shared by all members. 
D)  The core genome is the set of genes introduced by horizontal gene transfer, while the pan genome is the set of genes that is not transferred horizontally.

Question 15

The atmosphere of primitive Earth is usually classified as an oxidizing atmosphere.

Accepted Answer

A) True 
 B)False

Question 16

The earliest stromatolites were probably formed by

Accepted Answer

A)  anoxygenic phototrophs. 
B)  anoxygenic lithotrophs. 
C)  oxygenic phototrophs. 
D)  oxygenic lithotrophs.

Question 17

A monophyletic group is a group that

Accepted Answer

A)  descended from one ancestor. 
B)  has the same fitness level. 
C)  possesses one taxonomic trait that is the same. 
D)  shares one phylogenetic marker.

Question 18

As oxygen appeared in the atmosphere,________ also accumulated,which formed a protective barrier that protects the Earth from ________.

Accepted Answer

A)  ozone / UV radiation 
B)  elemental sulfur / volcanism 
C)  ferrous iron / hydroxylating radicals 
D)  sulfate / hydrogen sulfide

Question 19

Which of the following statements is FALSE concerning the universal tree of life?

Accepted Answer

A)  Previous versions of the universal tree of life were based largely on fossils and comparative biology, which overlooked the diversity of and relationships between most prokaryotes. 
B)  The current universal tree of life is supported by multiple genes including SSU rRNA sequences. 
C)  The current universal tree of life depicts three domains of life, two of which are prokaryotic. 
D)  The current universal tree of life is based on molecular sequences and completely changes our view of evolutionary relationships between eukaryotic species.

Question 20

LUCA is

Accepted Answer

A)  the last universal common ancestor. 
B)  the individual ancestor of each of the three domains. 
C)  actually somewhat of a misnomer because it is now believed that each of the domains arose independently. 
D)  All of the answers are correct.

Exam 12: Microbial Evolution and Systematics

How does the Black Queen Hypothesis explain the effect of gene deletions on bacterial evolution?

Chemical reactions involving ________ have been proposed as energy-yielding reactions for primitive organisms.

The earliest nucleic acid was probably a simple DNA molecule.

At present there are four phyla in the domain Bacteria.

Explain the strengths and limitations of using 16S rRNA for phylogenetic analyses.

It is believed that phototrophy arose approximately 3.3 billion years ago in

Which is NOT a characteristic of a "primitive" state of microbial evolution?

DNA:DNA hybridization is a sensitive method for revealing subtle genetic differences because it measures the degree of sequence similarity between two genomes.

What type of methods are used in microbial systematics? Why are multiple methods used to characterize and classify microbial species? Be sure to define the methods and describe the general strengths and weaknesses of each type.

Lateral gene transfer is one plausible explanation as to why organisms in Archaea,Bacteria,and Eukarya still share so many genes among such distinct domains.

Approximately 4 billion years ago Archaea and Bacteria diverged as being distinct from each other.

Both deletions and insertions occur during the evolution of microbial genomes.Insertions bring in new genes that may be useful for the cell,but deletions

Microbial species have a core genome and a pan genome.What is the difference between the two?

The atmosphere of primitive Earth is usually classified as an oxidizing atmosphere.

The earliest stromatolites were probably formed by

A monophyletic group is a group that

As oxygen appeared in the atmosphere, also accumulated,which formed a protective barrier that protects the Earth from .

Which of the following statements is FALSE concerning the universal tree of life?

LUCA is