Exam 26: Phylogeny and the Tree of Life

If cetaceans are determined to have diverged from the lineage leading to the artiodactyls before the divergence of lineages leading to the modern artiodactyls (including hippos), then the cetaceans can be considered 1. a sister order to the order Artiodactyla. 2. an ingroup of the order Artiodactyla. 3. the common ancestor of the order Artiodactyla.

What is true of the phylogeny in the above figure? 1. It is rooted. 2. The gibbons and siamangs represent an outgroup of the great apes. 3. Chimps and humans are the closest extant sister taxa depicted here. 4. It is absolute, meaning free of error. 5. The last common ancestor of the great apes lived about 14 million years ago.

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. 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 the above figure?

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

Use the following information and figure to answer the questions 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 the figure below). This figure contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage. -If it turns out that the whale lineage diverged from the lineage leading to hippos after the divergence of the lineage leading to the pigs and other artiodactyls, and if the whales continue to be classified in the order Cetacea, then what becomes true of the taxon Cetartiodactyla?

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?

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

Neutral theory proposes that

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

Use the following figure to answer the questions below. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago. Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. -From the above figure, to which of the extant apes are orangutans most closely related?

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

Paralogous genes that have lost the function of coding for any functional gene product are known as "pseudogenes." Which of these is a valid prediction regarding the fate of pseudogenes over evolutionary time?

Members of which kingdom have cell walls and are all heterotrophic?

The next questions refer to the following table, which compares the percent 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?

Use this figure to answer the following questions. -If the above figure is an accurate depiction of relatedness, then which of the following should be correct? 1. The entire tree is based on maximum parsimony. 2. If all species depicted here make up a taxon, this taxon is monophyletic. 3. The last common ancestor of species B and C occurred more recently than the last common ancestor of species D and E. 4. Species A is the direct ancestor of both species B and species C. 5. The species present at position 3 is ancestral to C, D, and E.

The best classification system is that which most closely

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

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

Why is the Kingdom Monera no longer part of the modern classification system?

Use the following information to answer the questions below. 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. Bird anatomy has become highly modified as birds 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?