Exam 20: Phylogeny

Figure 20.2 - Figure 20.3 In Figure 20.3, phylogeny branch lengths represent genetic changes. Which organism on the tree has undergone the most genetic changes since divergence from common ancestor?

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

A phylogenetic tree shows that birds and crocodiles share many features. A hypothesis based on this tree predicts that these features are present in a common ancestor. Which of these predicted traits is supported by fossil evidence?

According to the principle of maximum parsimony,

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

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

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

What evidence suggests that limbless bodies are the result of convergent evolution of snakes and lizards?

How does phylogeny differ from systematics?

In addition to naming species, Linnaeus also grouped species into a hierarchy of increasingly inclusive categories. The largest category that would include closely related species is

Please use the following information to answer the question(s) below. 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 20.5). Figure 20.5 -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?

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

A potential source of confusion in constructing a phylogeny tree is similarity between organisms that is due to

A polytomy on a phylogenetic tree represents

The relative lengths of the frog and mouse branches in the phylogenetic tree in the figure given below indicate that Figure 20.7

Please use the following information to answer the question(s) below. 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 20.5). Figure 20.5 -What can be properly inferred from Figure 20.5?

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

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 -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?

Please use the following information to answer the question(s) below. 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 20.5). Figure 20.5 -It was once thought that cetaceans had evolved from an extinct group of mammals called the mesonychids. If, in the future, it is determined that some organisms currently classified as cetaceans did actually evolve from mesonychids, whereas other cetaceans evolved from artiodactyl stock, then what will be true of the order Cetacea?

Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in