Exam 20: Phylogeny

A shared ancestral character is

How does a molecular clock measure time?

Figure 20.2 -Assuming chimpanzees 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

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

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?

What evidence allowed biologists to conclude that classification of the tree of life required a three-domain system?

Sister taxa

Which of these would, if it (they) had acted upon a gene, prevent this gene from acting as a reliable molecular clock?

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

The next question(s) refer to Table 20.1, 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 (for example, 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 the DNA of another member of species A. Table 20.1 -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?

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom?

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

You discover a fossil with feathers on forelimbs, short hind limbs, and teeth. You conclude that this organism appears early on a phylogenetic tree for which group of organisms?

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

To apply parsimony to constructing a phylogenetic tree,

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

Neutral theory proposes that

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

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