Exam 26: Phylogeny and the Tree of Life

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?

Which eukaryotic kingdom is polyphyletic, and therefore unacceptable, based on cladistics?

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

Use Figure 26.1 to answer the following questions. Figure 26.1 -If Figure 26.1 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.

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. -The great apes comprise the family Hominidae, whereas the lesser apes comprise the family Hylobatidae. If the extant organisms on the far right side of Figure 26.5 comprise the next-most exclusive (i.e., specific)taxon, then they comprise different

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

What is true of the phylogeny in Figure 26.5? 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.

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?

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

Nucleic acid sequences that undergo few changes over the course of evolutionary time are said to be conserved. Conserved sequences of nucleic acids

A) that these organisms are phenotypically more similar to each other than to any others shown on the trees in Figure 26.2. B) that their morphological similarities are probably homoplasies. C) that they had a common ancestor. D) that all three of the responses are correct. E) that two of the responses are correct. Answer: C -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 order Artiodactyla?

Together, the lesser apes and great apes shared a common ancestor most recently with other members of their