Question 1

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

Accepted Answer

The presence of antler-like structures in beetles, flies, and deer is unlikely to be due to shared ancestry, as these groups are evolutionarily distinct. It is also not an example of homology, as the antler-like structures evolved independently in each group. Parsimony is not relevant in this case. Therefore, the best explanation is convergent evolution, where similar adaptations evolve independently in different groups in response to similar selective pressures, in this case male-male competition.

Question 2

The importance of computers and of computer software to modern systematics s is most closely linked to advances in ________.

Accepted Answer

Computers and computer software have revolutionized systematics by allowing for the processing and analysis of vast amounts of molecular genetic data. This has led to significant advances in phylogenetic reconstruction and understanding of evolutionary relationships among species.

Question 3

The legless condition that is observed in several groups of extant reptiles is the result of ________.

Accepted Answer

The legless condition has arisen multiple times independently in extant reptiles, so it is not the result of a common ancestor or single adaptation. It is also not necessarily related to a particular lifestyle, as both arboreal and fossorial species can be legless. The leglessness may simply be a result of genetic mutations and natural selection in each independent lineage.

Question 4

Carolus Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with ________.

Accepted Answer

Linnaeus believed in the fixed nature of species and did not propose any evolutionary relationships among them. Phylogenies, on the other hand, depict the relationships and evolutionary history of organisms, which would contradict Linnaeus' belief.

Question 5

The following question refers to the following phylogenetic trees.

Which tree depicts the microsporidians as a sister group of the ascomycetes?

Accepted Answer

The answer of The following question refers to the following...

Question 6

The term convergent evolution is most applicable to which of the following features?

Accepted Answer

The legless condition found in various lineages of extant lizards is an example of convergent evolution. This is because the loss of limbs in these lizard lineages is not due to a shared ancestral trait, but instead arose independently in multiple lineages as an adaptation to similar environments.

Question 7

Based on this tree, which statement is correct?

Accepted Answer

The branching pattern indicates that the group containing lizards, goats, and humans is a clade, which means that they share a common ancestor more recently with each other than with any other group on the tree. Salamanders branch off earlier than this group, indicating they are a sister group to this clade, but not part of it. Therefore, option B is correct. Option A is incorrect because the human lineage is part of the clade with lizards and goats, so it is not a basal taxon. Option C is incorrect because salamanders are more distantly related to lizards than they are to humans. Option D is incorrect because goats and humans are part of the same clade, so they are more closely related to each other than to salamanders.

Question 8

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as ________.

Accepted Answer

The four-chambered hearts of birds and mammals are not due to shared ancestry, but rather have evolved independently. Therefore, they are not structural homologies or vestiges. They are best described as structural analogies, which are similar structures that have evolved independently in different lineages.

Question 9

The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical classification system differ from each other on the basis of ________.

Accepted Answer

The taxonomic levels of the hierarchical classification system differ on the basis of their inclusiveness, with each level including progressively more specific groups of organisms. Factors like distribution and genome size are not used to determine taxonomic classification, and morphological characters may not be applicable to all organisms.

Question 10

Imagine that a phylogeny was developed for a group of mammals based on bone structure. Which of the following statements would be a reasonable prediction about a phylogeny for the same group of species based on similarities and differences in the structure of a particular enzyme?

Accepted Answer

Bone structure and enzyme structure are different types of data sets and may not necessarily reflect the same evolutionary relationships. Therefore, it is unlikely that the same phylogeny would be predicted.

Question 11

The following question refers to the following phylogenetic trees.

Which tree depicts the closest relationship between zygomycetes and chytrids?

Accepted Answer

The answer of The following question refers to the following...

Question 12

If organisms A, B, and C belong to the same class but to different orders and if organisms C, D, and E belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology?

Accepted Answer

Organisms D and E belong to the same order and therefore are expected to have a higher degree of structural homology than organisms belonging to different orders (such as A and D, or B and D). The fact that organisms C, D, and E belong to the same order also suggests that they share certain structural characteristics.

Question 13

The following question refers to the following phylogenetic trees.

Which tree shows the greatest evolutionary distance between chytrids and ascomycetes?

Accepted Answer

The answer of The following question refers to the following...

Question 14

Use the following information to answer the question.
Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics.
In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species. (T. Monis, et al. 1999. Molecular systematics of the parasitic protozoan Giardia intestinalis. Mol. Biol. Evol. 16[9]:1135-44.)

According to the phylogenetic tree in the figure above, G. intestinalis constitutes a ________ group.

Accepted Answer

The answer of Use the following information to answer the...

Question 15

The following phylogeny shows six living species (a-f) and five ancestral (now extinct) species (#1-5). If the phylogeny had been developed on the basis of similarities in bone structure, which of the following predictions would you make in terms of the structure of a particular enzyme?

Accepted Answer

Since the phylogeny is based on similarities in bone structure, we can assume that species with closer ancestral relationships will share more similarities in their bone structure. Therefore, we can predict that the enzymes of species b and c are more similar to ancestor #4 (the common ancestor of b and c) than to ancestor #2 (the common ancestor of a, d, e, and f).

Question 16

The best classification system is that which most closely ________.

Accepted Answer

The most accurate and useful classification system is one that reflects evolutionary history, as it reflects the relationships and genetic similarities between organisms. Morphologies can be deceiving and do not always accurately depict evolutionary relationships, and traditional Linnaean taxonomic practices are outdated and not necessarily reflective of true relationships. Separating prokaryotes from eukaryotes is only one aspect of classification and does not provide a comprehensive classification system.

Question 17

If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be ________.

Accepted Answer

Convergent evolution is the process where organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. The similarity in rRNA sequences could be due to convergent evolution rather than direct common ancestry.

Question 18

Which of the following pairs are the best examples of homologous structures?

Accepted Answer

Homologous structures are those that have similar bones or structures that are derived from a common ancestor. The bones in the bat wing and the human forelimb have a similar bone structure, suggesting that they evolved from a common ancestor. On the other hand, the other options do not have a common ancestor that suggests homology (A and B), or are analogous rather than homologous (C).

Question 19

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). If the molecular data best reflect the evolutionary history of these two groups, then the morphological similarities of these two species is most likely due to ________.

Accepted Answer

Possession of analogous (convergent) traits. This is because the molecular data shows that the two species are not closely related, but they share similar morphological features. This is likely due to the evolutionary process of convergent evolution, where unrelated species evolve similarities due to similar selective pressures in their environments.

Question 20

In the 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 phylogenetic trees, numbers represent species,...

Quiz 26: Phylogeny and the Tree of Life

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

The importance of computers and of computer software to modern systematics s is most closely linked to advances in ________.

The legless condition that is observed in several groups of extant reptiles is the result of ________.

Carolus Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with ________.

The following question refers to the following phylogenetic trees. Which tree depicts the microsporidians as a sister group of the ascomycetes?

The term convergent evolution is most applicable to which of the following features?

Based on this tree, which statement is correct?

The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical classification system differ from each other on the basis of ________.

Imagine that a phylogeny was developed for a group of mammals based on bone structure. Which of the following statements would be a reasonable prediction about a phylogeny for the same group of species based on similarities and differences in the structure of a particular enzyme?

The following question refers to the following phylogenetic trees. Which tree depicts the closest relationship between zygomycetes and chytrids?

If organisms A, B, and C belong to the same class but to different orders and if organisms C, D, and E belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology?

The following question refers to the following phylogenetic trees. Which tree shows the greatest evolutionary distance between chytrids and ascomycetes?

The following phylogeny shows six living species (a-f) and five ancestral (now extinct) species (#1-5) . If the phylogeny had been developed on the basis of similarities in bone structure, which of the following predictions would you make in terms of the structure of a particular enzyme?

The best classification system is that which most closely ________.

If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be ________.

Which of the following pairs are the best examples of homologous structures?

In the 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?