Exam 26: Phylogeny and the Tree of Life

Which kind of DNA should provide the best molecular clock for determining the evolutionary relatedness of several species whose common ancestor became extinct billions of years ago?

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

Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient proteobacterium and an ancient cyanobacterium?

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

In a comparison of birds and mammals, having four limbs is

The best classification system is that which most closely

Which of these can be properly inferred from the phylogeny in Figure 26.5?

Species that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their

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

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology?

A) that these organisms are phenotypically more similar to each other than to any others shown on the trees in Figure 26.2. B) that their morphological similarities are probably homoplasies. C) that they had a common ancestor. D) that all three of the responses are correct. E) that two of the responses are correct. Answer: C -One morphological feature of modern cetaceans is a vestigial pelvic girdle. If it is determined that cetacean lineage diverged from the artiodactyls' lineage after the divergence of pigs and other artiodactyla, then what should be true of the vestigial pelvic girdle of cetaceans?

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 ________.

A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or 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 the following is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged?

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. Figure 26.4. A possible phylogenetic tree for the three domains of life. -Which portion of Figure 26.4 may ultimately be better depicted as a "ring"?

To apply parsimony to constructing a phylogenetic tree,

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. Figure 26.4. A possible phylogenetic tree for the three domains of life. -If the early history of life on Earth is accurately depicted by Figure 26.4, then which statement is least in agreement with the hypothesis proposed by this tree?

Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade and placing them in a different clade has the effect of making the phylogenetic tree of the great apes

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

When it acts upon a gene, which of the following processes consequently makes that gene an accurate molecular clock?

The next questions refer to the following table, which compares the % sequence homology of four different parts (two introns and two 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 the one 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. % Sequence Homology -Which of the following is the best explanation for the high degree of sequence homology observed in Exon I among these five species?