Exam 26: Phylogeny and the Tree of Life

The most important feature that permits a gene to act as a molecular clock is ________.

Which of the following statements about horizontal gene transfer is accurate?

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 this phylogenetic tree, depicting the origins of life and the three domains. Horizontal lines indicate instances of gene or genome transfer. A possible phylogenetic tree for the three domains of life. -If the early history of life on Earth is accurately depicted by the figure, then which statement is most in agreement with the hypothesis proposed by this tree?

- Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2 in the figure?

Refer to the figure. Which of the following forms a monophyletic group?

The relative lengths of the frog and mouse branches in the phylogenetic tree above indicate that

Based on cladistics, which eukaryotic kingdom is polyphyletic and, therefore, unacceptable?

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.) - By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?

Which of the following statements is accurate, at least according to our present knowledge?

Which of the following statements is accurate with regard to a phylogeny, as represented by a phylogenetic tree?

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

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up

A phylogenetic tree is shown for the three domains of life (Eukarya, Archaea, and Bacteria). The tree branches in two directions from the first point, labelled Common ancestor of all life. One branch leads in the direction of Eukarya and Archaea, and the other branch leads to Bacteria. The branch leading to Eukarya and Archaea divide, one branch leading to each domain. The branch leading to Eukarya divides into four branches. One leads to Euglenozoans, and the other three lead to branching points. The first leads to Forams in one direction, and another branching point in the other that leads to Diatoms and Ciliates. The second branching point leads to Red algae in one direction, and a branching point that leads to green algae and land plants in the other direction. The third branching point leads to amoebas in one direction, and a branching point that leads to fungi and animals in the other direction. Land plants, Fungi and Animals are all highlighted. Examine the figure. If you were a graduate student trying to develop a thesis project that would resolve polytomies, which of the following groups would you study?

-Which tree depicts the closest relationship between zygomycetes and chytrids?

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

Molecular clocks are more reliable when ________.

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?

If additional DNA sequence evidence shows that yeast genes for synthesising proteins are more similar to protein-synthesising genes in bacteria than those in archaea, a modern systematist would ________.