Question 1

You have found fossils of a new species of ape that walks upright. After 11 additional years in the field you discover a fossil of what you think is the common ancestor of the new species of ape and all other gorillas. What types of data would give you the BEST information on the environment of this ancestral organism?

Accepted Answer

A) gene sequencing of the new species of ape 
B) anatomical features of the new species of ape 
C) behavior of the new species of ape 
D) fossils of plants and animals found with the fossilized common ancestor 
E) anatomical features of the fossilized common ancestor

Question 2

The phylogeny below shows:  (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.

Accepted Answer

A) orangutans and gorillas are more closely related than humans and gorillas. 
B) humans and gorillas are more closely related than orangutans and gorillas. 
C) the gorilla is the most recent common ancestor to bonobos, chimps, and humans. 
D) the orangutan is the most recent common ancestor of all great apes. 
E) all great apes walk with an upright gait.

Question 3

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? $$\begin{array} { | l | c | c | c | c | } 
\hline & \text { Species A } & \text { Species B } & \text { Species C } & \text { Species D } \
\hline \begin{array} { l } 
\text { Presence of } \
\text { sepals }
\end{array} & \text { yes } & \text { yes } & \text { yes } & \text { no } \
\hline \begin{array} { l } 
\text { Number of } \
\text { petals }
\end{array} & \text { five } & \text { five } & \text { ten } & \text { ten } \
\hline \begin{array} { l } 
\text { Arrangement of } \
\text { petals }
\end{array} & \text { whorled } & \text { whorled } & \text { whorled } & \text { whorled } \
\hline \begin{array} { l } 
\text { Number of } \
\text { carpels }
\end{array} & \text { ten } & \text { ten } & \text { ten } & \text { five } \
\hline
\end{array}$$

Accepted Answer

A) presence of sepals 
B) number of petals 
C) arrangement of petals 
D) number of carpels

Question 4

The specific types of homologies used to develop phylogenies are shared derived characters or:

Accepted Answer

A) sister groups. 
B) convergent characteristics. 
C) synapomorphies. 
D) parsimonious branches.

Question 5

The half-life of 14C is 5730 years. If a sample contained 100% 14C and 0% 14N at a point in time 17,190 years ago, then what percentage of 14C would it contain today?

Accepted Answer

A) 12.5% 
B) 25% 
C) 50% 
D) 75% 
E) 100%

Question 6

In 2027, an unmanned rover lands on Mars, scoops pieces of ancient sedimentary rock into its interior, and then makes careful chemical analyses. Back on Earth, scientists are astonished to find that the rocks contain traces of RNA, much like that in ribosomes. Some of the scientists conclude that the rover has found evidence of Martian life, while others interpret the presence of RNA as evidence that the rover was contaminated by microorganisms on Earth before launch. Statements 1-4 below list four possible outcomes of a molecular phylogenetic test of the two hypotheses. Rank the outcomes in order of INCREASING support for the hypothesis that life originated independently on Earth and Mars.
1) The RNA found by the rover has no close resemblance to that found in terrestrial organisms.
2) Molecular phylogenetic analyses place the Martian RNA close to that of the bacterium E. coli.
3) Molecular phylogenetic analyses place the Martian RNA as a sister group to all known RNAs of bacteria, archaea and eukaryotes.
4) Molecular phylogenetic analyses place the RNA near the bottom of the bacterial branch of the tree of life.

Accepted Answer

A) 1, 2, 3, 4 
B) 1, 2, 4, 3 
C) 1, 3, 2, 4 
D) 1, 3, 4, 2 
E) 1, 4, 3, 2

Question 7

The remarkable fossil of the "fishapod," Tiktaalik, which lived about 375 million years ago, is a beautiful example of an intermediate form, having the attributes of both fish (scales, fins) and tetrapods (a flat head, mobile neck). The presence of Tiktaalik and other fossils of other organisms that lived around the same time shows clear evidence that tetrapods were derived from fish, implying that the grouping "fish" is paraphyletic. Imagine now that there was no fossil record. Would it still be possible to determine whether or not "fish" is paraphyletic?

Accepted Answer

The answer of The remarkable fossil of the "fishapod," Tiktaalik,...

Question 8

According to the fossil record, when did the earliest animals appear on Earth?

Accepted Answer

A) 580 million years ago 
B) 3 billion years ago 
C) 3500 million years ago 
D) 520 million years ago 
E) 55 million years ago

Question 9

The phylogeny below was generated using molecular data.  C is the node representing the common ancestor of humans and chimpanzees; B is the node representing the common ancestor of the cow and human/chimpanzee lineages; A is the node representing the common ancestor of the salmon and cow/human/chimpanzee lineages. Imagine that a researcher is interested in finding the approximate dates of A, B, and C. Give two approaches that would help resolve the timing of the nodes in the phylogeny.

Accepted Answer

The answer of The phylogeny below was generated using molecular...

Question 10

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?

Accepted Answer

A) 3 
B) 12 
C) 15 
D) 24 
E) 32

Question 11

Based on the phylogenetic tree in Fig. 23.22, what character did the last common ancestor of both reptiles and mammals NOT possess?

Accepted Answer

A) lungs 
B) four limbs 
C) amniote embryos 
D) mammary glands 
E) The last common ancestor of reptiles and mammals possessed all of these traits.

Question 12

Examine Figure 23.2 below.  According to the figure, the closest relatives of turtles are:

Accepted Answer

A) lizards and snakes. 
B) sauropsids. 
C) tetrapods. 
D) crocodiles, alligators, and birds. 
E) hagfish.

Question 13

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?

Accepted Answer

A) phylogeny I 
B) phylogeny II 
C) Both phylogenetic trees have the same number of evolutionary steps.

Question 14

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

Accepted Answer

A) fewest 
B) three 
C) four 
D) most

Question 15

Examine Figure 23.2 below.  If we defined a taxon to include only the coelacanths and lungfish but not their most recent common ancestor, it would be a _____ group.

Accepted Answer

A) monophyletic 
B) paraphyletic 
C) polyphyletic

Question 16

According to Figure 23.2 below, the most recent common ancestor of a bird and a turtle is also the most recent common ancestor of a bird and which other group?

Accepted Answer

A) snake 
B) human 
C) crocodile 
D) frog 
E) None of the answer options is correct.

Question 17

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?

Accepted Answer

A) 0% 
B) 25% 
C) 50% 
D) 75% 
E) 100%

Question 18

Phylogenetic reconstruction based on shared derived characters is called:

Accepted Answer

A) synapomorphy. 
B) cladistics. 
C) monophyly. 
D) taxonomy.

Question 19

Which of the following character states would be MOST helpful in identifying sister groups?

Accepted Answer

A) character states that occur only within a single species 
B) character states that occur in all descendants of a distant common ancestor 
C) homologies that are only found in some, but not all, the members of a single group 
D) analogies found in organisms belonging to different groups, and which do not share a common ancestor

Question 20

Which of the following statements is TRUE regarding a phylogenetic tree?

Accepted Answer

A) Phylogenetic trees could be considered physical representations of hypothesesF1F1F1S1F1F1F10those that seek to establish the evolutionary relationships between different organisms. 
B) Given the sheer number of prokaryotic and eukaryotic species on Earth, it is impossible to create a phylogenetic tree encompassing all of these organisms. 
C) Phylogenetic trees are constructed based solely on the morphological characteristics of species; sequence similarities among different organisms are only evaluated by taxonomists. 
D) Within a phylogenetic tree, the order of groups located at the tree tipsF1F1F1S1F1F1F10not the nodes within a treeF1F1F1S1F1F1F10determines sister group relationships. 
E) Phylogenetic trees only depict the evolutionary relationships between different classes; relationships among different species within the same genus are not illustrated in such trees.

Exam 23: Evolutionary Patterns: Phylogeny and Fossils

The phylogeny below shows: (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.

The specific types of homologies used to develop phylogenies are shared derived characters or:

The half-life of ¹⁴C is 5730 years. If a sample contained 100% ¹⁴C and 0% ¹⁴N at a point in time 17,190 years ago, then what percentage of ¹⁴C would it contain today?