Question 1

We know the streamlined bodies shown in the accompanying figure are examples of homoplasy. If the following groups also had streamlined bodies, which of the groupings would give the most support to this body type being homologous?

Accepted Answer

D

Question 2

The approach to estimating phylogenetic trees is most like the approach of which species concept?

Accepted Answer

Estimating phylogenetic trees involves using molecular data to determine the evolutionary relatedness of species, which aligns with the phylogenetic species concept that defines species based on their evolutionary history and genetic characteristics. The morphological species concept relies on physical characteristics, the biological species concept focuses on reproductive compatibility, and the subspecies concept considers variations within a single species.

Question 3

Use the following tree to answer the question below.  Which of the following trees, if any, depicts the same relationship among species as shown above?

Accepted Answer

This tree has the same relationships between the species as the original tree. The other two trees have different relationships between the species.

Question 4

The term "homoplasy" is most applicable to which of the following features?

Accepted Answer

Homoplasy refers to the evolution of similar features in distinct lineages that do not share a common ancestor with that feature. The legless condition found in various lineages of extant lizards is an example of homoplasy as these lineages evolved this feature independently.

Question 5

Which of the following statements is TRUE about a phylogeny, as represented by a phylogenetic tree?
I. Descendant groups (branches) from the same node do not share any derived characters.
II. A monophyletic group can be properly based on convergent features.
III. The ancestral group always displays all the synapomorphies of the descendant species.

Accepted Answer

I. Descendant groups from the same node actually share derived characters, which is why they are grouped together in the first place. II. A monophyletic group should be based on shared derived characteristics (synapomorphies), not convergent features, which result from convergent evolution rather than shared ancestry. III. The ancestral group does not necessarily display all the synapomorphies of the descendant species; some of these characteristics may evolve after the divergence from the common ancestor.

Question 6

Considering the phylogenetic trees above as strictly hypothetical and applying the principle of parsimony to the trait "ability to fly," which of the two phylogenetic trees shown is better?

Accepted Answer

According to the principle of parsimony, the tree with the fewest number of evolutionary changes is preferred. In Tree 1, the trait "ability to fly" only requires one evolutionary change, whereas in Tree 2, it requires two evolutionary changes. Therefore, Tree 1 is the more parsimonious option.

Question 7

Some beetles and flies have antler-like structures on their heads, much like male deer do. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of ________.

Accepted Answer

Convergent evolution refers to the evolution of similar adaptations in unrelated organisms in response to similar selection pressures, such as male-male competition for mates. The presence of antler-like structures on the heads of beetles, flies, and deer is an example of convergent evolution. Synapomorphies are shared derived traits that are used to construct phylogenetic trees, homology refers to similarities due to common ancestry, and parsimony is a principle used to select the simplest explanation for a given set of data. None of these concepts fully explain the evolution of antler-like structures in unrelated organisms.

Question 8

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

Accepted Answer

The most likely reason the lily was given is for use as an outgroup. An outgroup is a taxon that is closely related to the study group but not a part of it. It is used as a reference point to determine the evolutionary relationships within the group being studied. In this case, the lily is likely a closely related taxon to the orchids but not a part of the orchid group, providing a reference point for identifying shared derived characters (synapomorphies) and homoplasies in the orchids.

Question 9

Which of the following is an example of homoplasy?

Accepted Answer

Homoplasy refers to a trait that is similar in two species due to convergent evolution, not common ancestry. Cell walls in plants and fungi are an example of homoplasy because they evolved independently in these two lineages.

Question 10

Use the following table to answer the question(s) below. 
-What conclusion is apparent from the data in the accompanying table?

Accepted Answer

The table shows that there is a significant increase in the number of Hox genes in vertebrates compared to invertebrates, but this increase cannot be solely attributed to the three duplications of the ancestral vertebrate Hox cluster.

Question 11

Both ancestral birds and ancestral mammals shared a common ancestor that was a terrestrial vertebrate. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?

Accepted Answer

The bones in the forelimbs of penguins and seals share homology, meaning they have a similar evolutionary origin, but the flippers of penguins and seals represent homoplasy, meaning they have similar functions but evolved independently.

Question 12

Given that phylogenies are based on shared derived characteristics, which of the following traits is useful in generating a phylogeny of species W, X, Y, and Z?

Accepted Answer

The answer of Given that phylogenies are based on shared...

Question 13

Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following would suggest that the relationship more likely represents homology instead of convergent evolution?

Accepted Answer

The fact that the two species share many proteins in common and have almost identical nucleotide sequences suggests a shared evolutionary history and genetic relationship, supporting the idea of homology rather than convergent evolution. The other options are not necessarily indicators of homology or convergent evolution.

Question 14

What must be TRUE of any organ described as vestigial?

Accepted Answer

A vestigial organ is a feature that was useful in an ancestor but has lost its original function in a current organism. Therefore, it must have been homologous (share common ancestry) with the feature in the ancestor. Homoplasy refers to a feature that has evolved independently in different lineages and is not due to common ancestry, so it does not necessarily have to be present in a vestigial organ.

Question 15

Ichthyosaurs, now extinct, were aquatic reptiles with dorsal fins and tails, similar to those of fish. Their most recent ancestors were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are ________.

Accepted Answer

The dorsal fins and tails of ichthyosaurs and fish are adaptations to a common environment (aquatic) and are examples of convergent evolution, as they evolved independently in different lineages. They are not homologous structures, as they did not evolve from a common ancestor that also had these structures.

Question 16

All things being equal, which of these is the most parsimonious explanation for the change in the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in the table above?

Accepted Answer

Occam's Razor or the principle of parsimony suggests that the simplest explanation, with the fewest assumptions, is often the most likely. In this case, option C suggests a single duplication event of the entire seven-gene cluster, which is a simpler explanation compared to the other options. Option A suggests seven independent duplications, option B suggests two duplications followed by loss and option D suggests multiple duplications of different clusters. Hence, option C is the most parsimonious explanation.

Question 17

Two competing hypotheses to account for the increase in the number of Hox genes from the last common ancestor of bilaterians to the last common ancestor of insects and vertebrates are: (1) a single duplication of the entire four-gene cluster, followed by the loss of one gene, and (2) three independent duplications of individual Hox genes. To prefer the first hypothesis on the basis of parsimony requires the assumption that ________.

Accepted Answer

The first hypothesis is preferred on the basis of parsimony because it assumes a single duplication of the entire four-gene cluster followed by loss of one gene, which is simpler than the second hypothesis that assumes three independent duplications of individual Hox genes. However, this assumption requires the belief that the duplication of a cluster of four Hox genes is equally likely to the duplication of a single Hox gene.

Question 18

Which of the following would be useful in creating a phylogenetic tree of a vertebrate taxon?
I. morphological data from fossil species
II. genetic sequences from living species
III. behavioral data from living species

Accepted Answer

Phylogenetic trees can be constructed using a variety of data types, including morphological data from fossil species to understand evolutionary relationships and physical changes over time, genetic sequences from living species to analyze genetic similarities and differences, and behavioral data from living species to infer evolutionary traits and relationships. All these data types contribute valuable information for constructing a comprehensive phylogenetic tree.

Question 19

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees?

Accepted Answer

The principle of parsimony assumes that the simplest explanation that fits the data is most likely correct. In the case of constructing phylogenetic trees, this means that similar characteristics among different species are more likely due to common ancestry than to convergent evolution (where different species evolve similar traits independently). Thus, the principle of parsimony can help researchers identify the most likely evolutionary relationships among different species. The other answer choices are either incorrect (A, C) or incomplete (D).

Question 20

In the accompanying phylogenetic trees, numbers represent species and the same species are shown in both trees. Which two species are represented as sister species in Tree 2 but are not shown as sister species in Tree 1?

Accepted Answer

The answer of  In the accompanying phylogenetic trees, numbers...

Quiz 25: Phylogenies and the History of Life