Exam 26: Phylogeny and the Tree of Life

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?

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

Use Figure 26.1 to answer the following questions. Figure 26.1 -Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2 in Figure 26.1?

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

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

For a proponent of PhyloCode classification, what is true of the reptile clade if birds are not included in it?

What important criterion was used in the late 1960s to distinguish between the three multicellular eukaryotic kingdoms of the five-kingdom classification system?

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

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

From Figure 26.5, which other event occurred closest in time to the divergence of gorillas from the lineage that led to humans and chimps?

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change. -Taxonomically, what should be done with the birds?

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

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

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

Figure 26.3. Morphologically, species A is very similar to four other species, B-E. Yet the nucleotide sequence deep within an intron in a gene shared by all five of these eukaryotic species is quite different in species A compared to that of the other four species when we study the nucleotides present at each position. -If the sequence of species A in Figure 26.3 differs from that of the other four species due to simple misalignment, then what should the computer software find when it compares the sequence of species A to those of the other four species?

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage. -Placing whales and hippos in the same clade means

Which of the following items does not necessarily exist in a simple linear relationship with the number of gene-duplication events when placed as the label on the vertical axis of the following graph?

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 of these processes can be included among those responsible for the horizontal components of Figure 26.4?

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 -Based on the tabular data, and assuming that time advances vertically, which cladogram (a type of phylogenetic tree)is the most likely depiction of the evolutionary relationships among these five species?

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change. -Traditional zoologists have long agreed that birds evolved from dinosaurs. What keeps such zoologists from agreeing that birds, like dinosaurs, should be considered reptiles?