Exam 26: Phylogeny and the Tree of Life

The following questions refer to the hypothetical patterns of taxonomic hierarchy shown in Figure 26.2. -If the eukaryotic condition arose, independently, several different times during evolutionary history, and if ancestors of these different lineages are extant and are classified in the domain Eukarya, then the domain Eukarya would be

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

The following questions refer to the table below, which compares the % sequence homology of four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is that closest to the promoter). The data reported for Species A were obtained by comparing DNA from one member of species A to another member of Species A. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { \%/ Sequence Homology }$ Species Intron I Exon I Intron VI Exon V A 100\% 100\% 100\% 100\% B 98\% 99\% 82\% 96\% C 98\% 99\% 89\% 96\% 99\% 99\% 92\% 97\% 98\% 99\% 80\% 94\% -Which of these four gene parts should allow the construction of the most accurate phylogenetic tree, assuming that this is the only part of the gene that has acted as a reliable molecular clock?

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

Darwin analogized the effects of evolution as the above-ground portion of a many-branched tree, with extant species being the tips of the twigs. The common ancestor of two species is most analogous to which anatomical tree part?

The following questions refer to the information below. A researcher compared the nucleotide sequences of a homologous gene from five different species of mammals with the homologous human gene. The sequence homology between each species' version of the gene and the human gene is presented as a percentage of similarity. Species Percentage Chimpanzee 99.7 Orangutan 98.6 Baboon 97.2 Rhesus Monkey 96.9 Rabbit 93.7 -Nucleic acid sequences that undergo few changes over the course of evolutionary time are said to be conserved. Conserved sequences of nucleic acids

A large proportion of archaeans are "extremophiles," so called because they inhabit extreme environments with high acidity and/or high temperature. Such environments are thought to have been much more common on the primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago. Which of these is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged?

Use Figure 26.1 to answer the following questions. Figure 26.1 -A common ancestor for both species C and E could be at position number

The following questions refer to the table below, which compares the % sequence homology of four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is that closest to the promoter). The data reported for Species A were obtained by comparing DNA from one member of species A to another member of Species A. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { \%/ Sequence Homology }$ Species Intron I Exon I Intron VI Exon V A 100\% 100\% 100\% 100\% B 98\% 99\% 82\% 96\% C 98\% 99\% 89\% 96\% 99\% 99\% 92\% 97\% 98\% 99\% 80\% 94\% -Which of these is the best explanation for Intron I's relatively high sequence homology among these five species?

Which curve in the graph below best depicts the way that mutation rate varies over time in a gene that can serve as a reliable molecular clock?

In a comparison of birds with mammals, having four appendages is

The following questions refer to the table below, which compares the % sequence homology of four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is that closest to the promoter). The data reported for Species A were obtained by comparing DNA from one member of species A to another member of Species A. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { \%/ Sequence Homology }$ Species Intron I Exon I Intron VI Exon V A 100\% 100\% 100\% 100\% B 98\% 99\% 82\% 96\% C 98\% 99\% 89\% 96\% 99\% 99\% 92\% 97\% 98\% 99\% 80\% 94\% -Which eukaryotic kingdom is polyphyletic and therefore not acceptable, based on cladistics?

The HIV genome's reliably high rate of change permits it to serve as a molecular clock. Which of these features is most responsible for this genome's high rate of change?

The following questions refer to this phylogenetic tree, depicting the origins of life and of the three domains. Horizontal lines indicate instances of gene or genome transfer. -If the early history of life on Earth is accurately depicted by this phylogenetic tree, then which statement is least in agreement with the hypothesis proposed by this tree?

The following questions refer to the table below, which compares the % sequence homology of four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is that closest to the promoter). The data reported for Species A were obtained by comparing DNA from one member of species A to another member of Species A. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { \%/ Sequence Homology }$ Species Intron I Exon I Intron VI Exon V A 100\% 100\% 100\% 100\% B 98\% 99\% 82\% 96\% C 98\% 99\% 89\% 96\% 99\% 99\% 92\% 97\% 98\% 99\% 80\% 94\% -Which of these is the best explanation for the relatively low level of sequence homology observed in Intron VI?

A phylogenetic tree that is "rooted" is one

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

The following questions refer to the table below, which compares the % sequence homology of four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is that closest to the promoter). The data reported for Species A were obtained by comparing DNA from one member of species A to another member of Species A. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { \%/ Sequence Homology }$ Species Intron I Exon I Intron VI Exon V A 100\% 100\% 100\% 100\% B 98\% 99\% 82\% 96\% C 98\% 99\% 89\% 96\% 99\% 99\% 92\% 97\% 98\% 99\% 80\% 94\% -Which is an obsolete kingdom that includes prokaryotic organisms?

Which of these illustrates the correct representation of the binomial scientific name for the African lion?

Based on this tree, which of the following statements is not correct?