Question 1

Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

Accepted Answer

A one-base substitution (also called a point mutation) involves only one nucleotide base being changed, whereas the other options involve the insertion or deletion of multiple nucleotides. Therefore, a one-base substitution would least require the realignment of homologous regions of a gene that is common to several related species.

Question 2

A researcher wants to determine the genetic relatedness of several breeds of dog (Canis lupus familiaris). The researcher should compare homologous sequences of this type of biochemical-________-which can be described as ________.

Accepted Answer

To determine genetic relatedness, the researcher should compare homologous sequences of nucleic acids, such as DNA or RNA, which can be variable among different breeds and thus poorly conserved. Comparing conserved sequences would not reveal differences that could be used to identify genetic relatedness. Comparing non-homologous sequences, such as lipids or fatty acids, would not provide information about genetic relatedness. Although proteins are also variable among different breeds, comparing them may not be as informative as comparing nucleic acids, since changes in the DNA sequence can ultimately affect the protein sequence. Comparing homologous sequences of amino acids is also an option, but since this usually implies comparing protein sequences, the explanation still applies.

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 independently in multiple groups of reptiles, suggesting it is not the result of a shared ancestor or adaptation to a specific habitat. It is unlikely that individual lizards adapting to a fossorial lifestyle during their lifetimes would result in the widespread occurrence of leglessness in certain groups of reptiles.

Question 4

When using a cladistic approach to systematics, which of the following is considered most important for classification?

Accepted Answer

Shared derived characters, also known as synapomorphies, are considered the most important for classification in a cladistic approach. These are traits that are shared by a group of organisms and their common ancestor but not found in more distantly related organisms. This allows for the creation of monophyletic groups, which have a common ancestor and all its descendants. Shared primitive characters (A) are traits found in both the organism being studied and its ancestors, but not in more closely related groups. Analogous primitive characters (B) are traits that are similar due to convergent evolution, but do not indicate a close evolutionary relationship. The number of homoplasies (D) is a consideration, but shared derived characters are still more important for classification. Overall phenotypic similarity (E) can be useful, but it does not necessarily indicate evolutionary relatedness.

Question 5

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

Accepted Answer

Bones in the bat wing and bones in the human forelimb are the best examples of homologous structures because they have the same basic bone structure despite their different functions. Both originated from a common ancestor that had similar bone structures in its forelimbs.

Question 6

If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F 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 F are in the same order and thus would be expected to have a higher degree of structural homology than organisms in different orders. Therefore, choice E, which pairs organisms D and F, would be expected to show the greatest degree of structural homology.

Question 7

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

Homoplasy refers to a similarity in the structure or genetic sequence of different species that is due to convergent evolution rather than to descent from a common ancestor. In the scenario described, the surprising similarity between human rRNA and that of an archaean cell, more so than between humans and mice, would likely be due to convergent evolution (homoplasy), rather than direct common ancestry. This is because archaea and humans are very distantly related on the evolutionary tree, with mice being much closer relatives to humans.

Question 8

Which individual would make the worst systematist? One who is uncomfortable with the

Accepted Answer

The answer of Which individual would make the worst systematist?...

Question 9

Which of the following is true of all horizontally oriented phylogenetic trees, where time advances to the right?

Accepted Answer

In horizontally oriented phylogenetic trees, time advances to the right, meaning that the common ancestor represented by the rightmost branch point is the most recent one. All other ancestors, represented at branch points to the left, existed further back in time.

Question 10

The various taxonomic levels (namely, genera, classes, etc.)of the hierarchical classification system differ from each other on the basis of

Accepted Answer

The taxonomic levels differ from each other based on their inclusiveness, meaning how many different types of organisms are included within each level. For example, a genus is less inclusive than a family, which is less inclusive than an order, and so on.

A, C, and D are not correct because they do not accurately describe how taxonomic levels are differentiated from one another.

Question 11

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with

Accepted Answer

Linnaeus' belief in fixed species would conflict with the concept of phylogenies, which suggest evolution and changes in species over time based on their ancestral relationships.

Answer: D
 Linnaeus' fixed species concept would not allow for the idea of nested, ever-more inclusive categories of organisms, as it implies that there is a continuum of change and evolution over time.

Answer: E
 Linnaeus' belief in fixed species would conflict with the hierarchical classification scheme, which is based on evolutionary relationships and suggests that organisms have changed over time and been influenced by their environment.

Question 12

The best classification system is that which most closely

Accepted Answer

The best classification system is one that reflects evolutionary history, as this allows for a better understanding of the relationships and ancestry between different groups of organisms. Morphology-based classification systems can be misleading, as organisms with different appearances can have similar DNA and evolutionary histories, while Linnaean taxonomic practices are arbitrary and based on subjective criteria. The separation of prokaryotes and eukaryotes is also not sufficient for a comprehensive classification system.

Question 13

Cladograms (a type of phylogenetic tree)constructed from evidence from molecular systematics are based on similarities in

Accepted Answer

Cladograms constructed from evidence from molecular systematics are based on similarities in mutations to homologous genes. Molecular systematics is a method of analyzing genetic material - particularly DNA and RNA sequences - to determine evolutionary relationships between organisms. Therefore, similarities in mutations to homologous genes provide the best evidence for constructing a cladogram that reflects these evolutionary relationships.

Question 14

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

Accepted Answer

Homoplasy refers to the occurrence of similar features in different lineages of organisms that are the result of convergent evolution, parallel evolution, or evolutionary reversal. The legless condition in various lineages of lizards is an example of convergent evolution, where similar adaptations evolve independently in different lineages.

Question 15

Concerning growth in genome size over evolutionary time, which of these is least associated with the others?

Accepted Answer

Orthologous genes are genes in different species that evolved from a common ancestral gene by speciation. Genome size does not necessarily increase due to the presence or absence of orthologous genes. Gene duplications, paralogous genes, and gene families are all associated with an increase in genome size, as they result in the duplication and/or diversification of genes within a genome.

Question 16

Which of the following is (are)problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

Accepted Answer

Polyphyletic and paraphyletic taxa are problematic for constructing accurate phylogenies because they do not represent natural groups derived from a common ancestor. Polyphyletic groups consist of species with similar characteristics but different ancestors, while paraphyletic groups include some, but not all, descendants of a common ancestor. Monophyletic taxa, which include an ancestor and all its descendants, are ideal for reflecting evolutionary history.

Question 17

Some molecular data place the giant panda in the bear family (Ursidae)but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to

Accepted Answer

The morphological similarities between the giant panda and the lesser panda, despite their placement in different families based on molecular data, suggest that these similarities are due to analogous structures. Analogous structures arise from convergent evolution, where unrelated species develop similar traits independently, often due to similar environmental pressures or ecological roles, rather than from a common ancestor.

Question 18

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then what can be properly said of hair?

Accepted Answer

If cynodonts are reclassified as mammals, then hair would be considered a shared derived character of mammals, as it would have originated in a common ancestor of mammals, including cynodonts.

Question 19

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 best described as homoplasies, which means they are similar structures that evolved independently in the two lineages after their divergence from a common ancestor with a three-chambered heart. This is not due to direct inheritance from a common ancestor with a four-chambered heart (which would be shared ancestry), but rather convergent evolution where similar environmental pressures led to the development of similar structures.

Question 20

The importance of computers and of computer software to modern cladistics is most closely linked to advances in

Accepted Answer

Modern cladistics heavily relies on molecular genetics, which can produce vast amounts of data that require computational analysis. Computers and computer software are essential in analyzing these data and constructing phylogenetic trees.

Quiz 26: Phylogeny and the Tree of Life

Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

A researcher wants to determine the genetic relatedness of several breeds of dog (Canis lupus familiaris) . The researcher should compare homologous sequences of this type of biochemical--which can be described as .

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

When using a cladistic approach to systematics, which of the following is considered most important for classification?

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

If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F 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?

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 individual would make the worst systematist? One who is uncomfortable with the

Which of the following is true of all horizontally oriented phylogenetic trees, where time advances to the right?

The various taxonomic levels (namely, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with

The best classification system is that which most closely

Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in

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

Concerning growth in genome size over evolutionary time, which of these is least associated with the others?

Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae) . Consequently, the morphological similarities of these two species are probably due to

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then what can be properly said of hair?

The importance of computers and of computer software to modern cladistics is most closely linked to advances in

Quiz 26: Phylogeny and the Tree of Life

Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

A researcher wants to determine the genetic relatedness of several breeds of dog (Canis lupus familiaris) . The researcher should compare homologous sequences of this type of biochemical-________-which can be described as ________.

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

When using a cladistic approach to systematics, which of the following is considered most important for classification?

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

If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F 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?

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 individual would make the worst systematist? One who is uncomfortable with the

Which of the following is true of all horizontally oriented phylogenetic trees, where time advances to the right?

The various taxonomic levels (namely, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with

The best classification system is that which most closely

Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in

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

Concerning growth in genome size over evolutionary time, which of these is least associated with the others?

Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae) . Consequently, the morphological similarities of these two species are probably due to

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then what can be properly said of hair?

The importance of computers and of computer software to modern cladistics is most closely linked to advances in

A researcher wants to determine the genetic relatedness of several breeds of dog (Canis lupus familiaris) . The researcher should compare homologous sequences of this type of biochemical--which can be described as .