Question 1

When comparing trees with various hypotheses of evolutionary relationships among a group of animals, the tree with _____ changes would be the preferred candidate.
A)fewest
B)three
C)four
D)most

Accepted Answer

The principle of parsimony suggests that the simplest explanation is the most likely to be correct, and therefore the tree with the fewest changes (also known as the "most parsimonious" tree) would be the preferred candidate for explaining the evolutionary relationships among a group of animals. The other choices (B, C, and D) do not inherently make sense as selection criteria for candidate trees.

Question 2

Examine the following table of characters in four different species of flower. Based on the matrix, Derek concludes that species A is sister to the remaining three species. Wilma, in contrast, argues that species D is sister to all other species. Who is CORRECT? $$\begin{array} { | l | c | c | c | c | } 
\hline & \text { Species A } & \text { Species B } & \text { Species C } & \text { Species D } \
\hline \begin{array} { l } 
\text { Presence of } \
\text { sepals }
\end{array} & \text { yes } & \text { yes } & \text { yes } & \text { no } \
\hline \begin{array} { l } 
\text { Number of } \
\text { petals }
\end{array} & \text { five } & \text { five } & \text { ten } & \text { ten } \
\hline \begin{array} { l } 
\text { Arrangement of } \
\text { petals }
\end{array} & \text { whorled } & \text { whorled } & \text { whorled } & \text { whorled } \
\hline \begin{array} { l } 
\text { Number of } \
\text { carpels }
\end{array} & \text { ten } & \text { ten } & \text { ten } & \text { five } \
\hline
\end{array}$$

A)Derek is correct, as the tree that puts A as sister to all other species is the most parsimonious.
B)Wilma is correct, as the tree that puts D as sister to all other species is the most parsimonious.
C)Neither, because the most parsimonious tree puts species B as sister to all others.
D)We can't decide from the information given as trees with species A, B, or D as sister to all other species are equally parsimonious.

Accepted Answer

The answer of Examine the following table of characters in...

Question 3

Characters that are similar because of descent from a common ancestor are:
A)homologous.
B)analogous.
C)examples of convergent evolution.
D)synapomorphies.

Accepted Answer

Homologous characters are those that have a similar structure and origin because they were inherited from a common ancestor. Therefore, characters that are similar because of descent from a common ancestor are homologous. Analogous characters are those that have a similar function but a different structure and origin, which can occur through convergent evolution. Synapomorphies are shared derived traits that are used to define a clade (a group of organisms that share a common ancestor), but they do not necessarily indicate similarity because of descent from a common ancestor.

Question 4

You are given a fossil and told that approximately 3% of the ¹⁴C originally in the sample is still there. How old is your sample? (Note that ¹⁴C has a half-life of 5730 years). A)approximately 11,500 years B)approximately 17,000 years C)approximately 23,000 years D)approximately 29,000 years

Accepted Answer

The decay of ¹⁴C (which is a stand-in for Carbon-14) follows an exponential decay model. Given that the half-life of Carbon-14 is 5730 years and only 3% of the original amount remains, we can calculate the number of half-lives that have passed. The formula to calculate the number of half-lives is: $n = \frac{\log(\text{final amount/original amount})}{\log(1/2)}$. Substituting the given values, $n = \frac{\log(0.03)}{\log(0.5)} \approx 5$. Multiplying the number of half-lives by the half-life duration: $5 \times 5730 \approx 28650$ years, which rounds to approximately 29,000 years.

Question 5

Examine the following table of characters in four different species of flower. Based on the matrix, which character defines a synapomorphy shared by species A and B? $$\begin{array} { | l | c | c | c | c | } 
\hline & \text { Species A } & \text { Species B } & \text { Species C } & \text { Species D } \
\hline \begin{array} { l } 
\text { Presence of } \
\text { sepals }
\end{array} & \text { yes } & \text { yes } & \text { yes } & \text { no } \
\hline \begin{array} { l } 
\text { Number of } \
\text { petals }
\end{array} & \text { five } & \text { five } & \text { ten } & \text { ten } \
\hline \begin{array} { l } 
\text { Arrangement of } \
\text { petals }
\end{array} & \text { whorled } & \text { whorled } & \text { whorled } & \text { whorled } \
\hline \begin{array} { l } 
\text { Number of } \
\text { carpels }
\end{array} & \text { ten } & \text { ten } & \text { ten } & \text { five } \
\hline
\end{array}$$
A)presence of sepals
B)number of petals
C)arrangement of petals
D)number of carpels

Accepted Answer

The number of petals is a synapomorphy shared by species A and B, as both have five petals, distinguishing them from species C and D, which have ten.

Question 6

Streamlined bodies are common in many aquatic organisms: Dolphins, tuna, penguins, and sharks are all organisms that have streamlined bodies that reduce friction and drag. Body shape in each of these organisms would be considered an:
A)analogous character.
B)homologous character.
C)similar character.
D)natural character.

Accepted Answer

Streamlined bodies in dolphins, tuna, penguins, and sharks are considered analogous characters because they are adaptations that evolved independently in each lineage to solve the same problem of reducing friction and drag in water, rather than being inherited from a common ancestor.

Question 7

You are given a character matrix for four different taxa showing character states for eight different morphologic characters. How many alternative phylogenetic hypotheses can be generated with the four taxa?
A)3
B)12
C)15
D)24
E)32

Accepted Answer

For four taxa, the number of possible unrooted trees is given by the formula (2n-5)!!, where n is the number of taxa. For n=4, this results in (2*4-5)!! = 3!! = 3 x 1 = 3. However, since each tree can be rooted in three different ways, the total number of rooted trees is 3 x 5 = 15.

Question 8

Which molecular detail can be used to construct phylogenetic histories?
A)individual nucleotides
B)amino acids
C)RNA
D)All of these choices are correct.

Accepted Answer

All of the given choices can be used to construct phylogenetic histories. DNA and RNA sequences can be compared between different species to see the similarities and differences. Amino acid sequences can also be compared to see how they have evolved over time. Therefore, all of them are useful molecular details for constructing phylogenetic histories.

Question 9

Examine the following table of characters in four different species of flower. Based on the character matrix, which is MOST likely an ancestral trait for the group of species? $$\begin{array} { | l | c | c | c | c | } 
\hline & \text { Species A } & \text { Species B } & \text { Species C } & \text { Species D } \
\hline \begin{array} { l } 
\text { Presence of } \
\text { sepals }
\end{array} & \text { yes } & \text { yes } & \text { yes } & \text { no } \
\hline \begin{array} { l } 
\text { Number of } \
\text { petals }
\end{array} & \text { five } & \text { five } & \text { ten } & \text { ten } \
\hline \begin{array} { l } 
\text { Arrangement of } \
\text { petals }
\end{array} & \text { whorled } & \text { whorled } & \text { whorled } & \text { whorled } \
\hline \begin{array} { l } 
\text { Number of } \
\text { carpels }
\end{array} & \text { ten } & \text { ten } & \text { ten } & \text { five } \
\hline
\end{array}$$
A)presence of sepals
B)number of petals
C)arrangement of petals
D)number of carpels

Accepted Answer

The arrangement of petals (whorled) is the only trait shared by all four species, suggesting it is the most likely ancestral trait.

Question 10

Excluding the outgroup, taxon A, how many equivalent sister-group relationships are depicted between the two phylogenies given below? 
A)one
B)two
C)three
D)four
E)There are no equivalent sister-taxa shown between the two phylogenies.

Accepted Answer

The answer of Excluding the outgroup, taxon A, how many...

Question 11

Characters that are similar because of descent from a common ancestor are _____; characters that are similar due to convergent evolution are _____.
A)homologous; analogous
B)analogous; homologous

Accepted Answer

Homologous characters are those that have a similar structure and/or function because they are descended from a common ancestor. Analogous characters, on the other hand, have a similar structure and/or function due to convergent evolution - that is, they evolved independently in different lineages.

Question 12

Phylogenetic trees can be built using:
A)anatomical data.
B)molecular data.
C)visible characteristics only.
D)anatomical data or molecular data.

Accepted Answer

Phylogenetic trees are typically constructed using either anatomical data or molecular data. However, the best approach is to use both anatomical and molecular data together for the most accurate representation of evolutionary relationships. Therefore, the correct answer is D, anatomical data or molecular data.

Question 13

To be useful for phylogenetic reconstruction, a taxonomic character must exhibit which of the following properties?
A)It must vary among the taxa being analyzed, but not within individual taxa.
B)It must have a genetic basis.
C)It must be anatomical.
D)It must be molecular (DNA or protein).
E)None of the other answer options is correct.

Accepted Answer

The answer of To be useful for phylogenetic reconstruction, a...

Question 14

The same intron was sequenced from five different taxa (taxa A-E) whose evolutionary relationships are disputed. The data matrix given shows six variable sites (1-6, left column) in the DNA sequences obtained from each of the five species. Taxon A serves as the outgroup for this analysis. $\begin{array}{|c|c|c|c|c|c|}
\hline & \operatorname{taxon} \mathrm{A} & \operatorname{tax} n \mathrm{~B} & \operatorname{tax} n \mathrm{C} & \operatorname{taxon} \mathrm{D} & \operatorname{taxon} \mathrm{E} \
\hline 1 & \mathrm{~A} & \mathrm{G} & \mathrm{G} & \mathrm{G} & \mathrm{G} \
\hline 2 & \mathrm{C} & \mathrm{T} & \mathrm{T} & \mathrm{T} & \mathrm{T} \
\hline 3 & \mathrm{G} & \mathrm{G} & \mathrm{G} & \mathrm{G} & \mathrm{A} \
\hline 4 & \mathrm{~A} & \mathrm{~A} & \mathrm{~T} & \mathrm{~A} & \mathrm{~T} \
\hline 5 & \mathrm{~A} & \mathrm{C} & \mathrm{A} & \mathrm{C} & \mathrm{C} \
\hline 6 & \mathrm{~A} & \mathrm{~A} & \mathrm{C} & \mathrm{A} & \mathrm{C} \
\hline
\end{array}$ Which of the phylogenies below explains the relatedness between these taxa with the FEWEST evolutionary steps? 
A)phylogeny I
B)phylogeny II
C)Both phylogenetic trees have the same number of evolutionary steps.

Accepted Answer

The answer of The same intron was sequenced from five...

Question 15

You find a fossil that you think is about 350 million years old. You decide to use ²³⁵U to date a volcanic ash bed just below the key specimen. If you are correct, what approximate percentage of the original ²³⁵U would you expect to remain in your sample? A)0% B)25% C)50% D)75% E)100%

Accepted Answer

The answer of You find a fossil that you think...

Question 16

While taking a hike in the forest, you find some fossils in layers of sedimentary rocks whose age, you later find out, is said to cover a span of 100-400 million years. You decide to send the fossils out for analysis to a company that dates rocks by radioactive decay, and, some weeks later, receive a report informing you that a volcanic ash bed associated with one of the fossils has a 1:1 ratio of ²³⁵U: ²⁰⁷Pb. Do these data support or refute the assumed age of the rocks in which the fossil was found? (Note: The half-life of ²³⁵U is about 704 million years.) A)Yes, because the rock layers are less than 704 million years old. B)Yes, because the ratio of ²³⁵U to ²⁰⁷Pb represents one half-life and that would be approximately 350 million years old. C)No, because the ratio of ²³⁵U to ²⁰⁷Pb represents one half-life and that would be about 700 million years old. D)No, because the rock layers are less than 704 million years old.

Accepted Answer

The 1:1 ratio of ²³⁵U to ²⁰⁷Pb indicates that one half-life has passed, which is approximately 704 million years, thus supporting an age older than the initially assumed 100-400 million years.

Question 17

When selecting among multiple possible phylogenetic trees that fit our data, we commonly use the principle of _____, which means we choose the _____ possible hypothesis. In phylogenetic analysis, that means selecting the tree that represents the _____ evolutionary changes or mutations.
A)parsimony; simplest; fewest
B)parsimony; simplest; most
C)parsimony; most; likely
D)phylogenetics; simplest; fewest
E)phylogenetics; simplest; most

Accepted Answer

The principle of parsimony requires choosing the simplest possible explanation that fits the data, which in phylogenetic analysis means selecting the tree that requires the fewest evolutionary changes or mutations.

Question 18

With the advent of tools to incorporate molecular data, phylogenetic analysis can be used to:
A)reconstruct the evolutionary history of a group of organisms over millions of years.
B)track the spread of a pathogen, such as a fungus or virus, from place to place.
C)identify the origin of invasive pest species.
D)track shipments of endangered species or their products (such as elephant ivory or bushmeat).
E)All of these choices are correct.

Accepted Answer

Phylogenetic analysis can be used for all the given purposes, as it reconstructs evolutionary history, tracks the spread of organisms or pathogens, identifies origins and tracks shipments of endangered species.

Question 19

You discover a new species of ape that is more closely related to gorillas than to any other species of ape, but walks upright. How would you change the phylogeny below?  Photo sources: (left to right) Zoonar/K. Jorgensen/age fotostock; S Sailer/A Sailer/age fotostock; J & C Sohns/age fotostock; Michael Dick/ Animals Animals-Earth Scenes; FLPA/Jurgen & Christi/age fotostock; Yellow Dog Productions/Getty Images.
A)I would not change the phylogeny at all because only molecular data are considered when studying evolutionary relationships.
B)I would not change the phylogeny at all until a fossil of the new species is found because fossil evidence is a required component of the data set.
C)I would group gorillas with humans based on the synapomorphy (shared trait)of upright stance.
D)I would branch the gorilla lineage and add the new species sister to gorillas.

Accepted Answer

Since the new species is more closely related to gorillas than to any other species of ape, it should be added as a sister species to the gorilla lineage. Even though it walks upright, this trait alone does not warrant grouping gorillas with humans, as they have many other differences. Additionally, while fossil evidence can provide important information about evolutionary relationships, it is not the only source of data considered when constructing a phylogeny.

Question 20

The same intron was sequenced from five different taxa (taxa A-E) whose evolutionary relationships are disputed. The data matrix given shows six variable sites (1-6 in left column) in the DNA sequences obtained from each of the five species. Taxon A serves as the outgroup for this analysis. $\begin{array}{|c|c|c|c|c|c|}
\hline & \operatorname{taxon} \mathrm{A} & \operatorname{tax} n \mathrm{~B} & \operatorname{tax} n \mathrm{C} & \operatorname{taxon} \mathrm{D} & \operatorname{taxon} \mathrm{E} \
\hline 1 & \mathrm{~A} & \mathrm{G} & \mathrm{G} & \mathrm{G} & \mathrm{G} \
\hline 2 & \mathrm{C} & \mathrm{T} & \mathrm{T} & \mathrm{T} & \mathrm{T} \
\hline 3 & \mathrm{G} & \mathrm{G} & \mathrm{G} & \mathrm{G} & \mathrm{A} \
\hline 4 & \mathrm{~A} & \mathrm{~A} & \mathrm{~T} & \mathrm{~A} & \mathrm{~T} \
\hline 5 & \mathrm{~A} & \mathrm{C} & \mathrm{A} & \mathrm{C} & \mathrm{C} \
\hline 6 & \mathrm{~A} & \mathrm{~A} & \mathrm{C} & \mathrm{A} & \mathrm{C} \
\hline
\end{array}$ Which of the phylogenies below explains the relatedness between these taxa with the FEWEST evolutionary steps? 
A)phylogeny I
B)phylogeny II
C)Both phylogenetic trees have the same number of evolutionary steps.

Accepted Answer

The answer of The same intron was sequenced from five...

Quiz 23: Evolutionary Patterns: Phylogeny and Fossils

When comparing trees with various hypotheses of evolutionary relationships among a group of animals, the tree with _____ changes would be the preferred candidate.

Characters that are similar because of descent from a common ancestor are:

You are given a fossil and told that approximately 3% of the ¹⁴C originally in the sample is still there. How old is your sample? (Note that ¹⁴C has a half-life of 5730 years) .

Streamlined bodies are common in many aquatic organisms: Dolphins, tuna, penguins, and sharks are all organisms that have streamlined bodies that reduce friction and drag. Body shape in each of these organisms would be considered an:

You are given a character matrix for four different taxa showing character states for eight different morphologic characters. How many alternative phylogenetic hypotheses can be generated with the four taxa?

Which molecular detail can be used to construct phylogenetic histories?

Excluding the outgroup, taxon A, how many equivalent sister-group relationships are depicted between the two phylogenies given below?

Characters that are similar because of descent from a common ancestor are _; characters that are similar due to convergent evolution are _.

Phylogenetic trees can be built using:

To be useful for phylogenetic reconstruction, a taxonomic character must exhibit which of the following properties?

You find a fossil that you think is about 350 million years old. You decide to use ²³⁵U to date a volcanic ash bed just below the key specimen. If you are correct, what approximate percentage of the original ²³⁵U would you expect to remain in your sample?

When selecting among multiple possible phylogenetic trees that fit our data, we commonly use the principle of ___, which means we choose the _ possible hypothesis. In phylogenetic analysis, that means selecting the tree that represents the ___ evolutionary changes or mutations.

With the advent of tools to incorporate molecular data, phylogenetic analysis can be used to: