Exam 21: Reconstructing and Using Phylogenies

Some species in a hypothetical family of beetles are winged, and others are wingless.Which would be most useful in determining whether having wings or being wingless was the ancestral trait?

From a survey of Martian life, three hypothetical species are found.These are nicknamed krons, furs, and pars.If krons and furs are sister species, the resulting phylogenetic tree will have 45 homoplasies.If krons and pars are sister species, the tree will have 52 homoplasies.Krons and pars have red body patches, whereas krons and furs have striped bodies.Based on the principles of parsimony, krons and _______ are sister species, _______ a synapomorphy.

Refer to the figure showing a single viral plaque that was split every 400 generations and grown in the presence of a mutagen. Based on this tree, which lineage should share the most synapomorphies with the E lineage?

Two species of flies share traits, such as head morphology and the shape of their genitalia, traits that other related species do not have.These shared characteristics are called

Humans and chimpanzees diverged about 6 million years ago.If 20 nucleotide substitutions have occurred between human and chimpanzee lineages in a sequence of mitochondrial DNA, and 30 have occurred between humans and gorillas, then, according to the molecular clock hypothesis, humans and gorillas separated _______ million years ago.

In studies involving the molecular clock,the fossil record

Consider five species of toads (A-E).Species A and B are sister species.Species C and D are also sister species.The clade containing species A and B is a sister to the clade containing species C and D.Which species groups would be a clade?

Which is not an advantage of fossil evidence in phylogenetic systematics?

Some species in a hypothetical family of plants are hermaphrodites, and others have flowers with separate sexes.What would be most useful in determining which condition was the derived one?

Suppose a particular amino acid variant in a protein appeared several times in the phylogeny of a group of yeasts.Species with the variant were often sister to species without the change.The species with the variant generally lived in conditions with higher concentrations of ethanol.What would be the most plausible explanation for this variant?

Tribolium castaneum is a beetle found in flour and other stored products.Tribolium is the name of the _______ to which this beetle belongs.This taxonomic category includes many species, and is the least inclusive standard taxonomic category.

The common ancestor of all of the species displayed in a phylogenetic tree lies at the _______ of the tree.

A trait that evolved by convergent evolution in more than one clade is

Which taxonomic category is the next largest after order?

The common ancestor of humans and chimpanzees lived about 7 million years ago.Based on a molecular clock, if a slowly evolving gene shows 3 percent divergence between humans and chimpanzees and 12 percent divergence between humans and gibbons, then humans and gibbons diverged from each other _______ years ago.

Species A and species B have long wings, whereas species C has short wings.Which piece of evidence would best support the hypothesis that long wings are a synapomorphy?

Refer to the figure. Which statement about the phylogenetic tree (shown) is true?

Refer to the phylogenetic tree below showing the phylogenetic relationships among eight species.Red dots indicate the appearance of derived traits. According to the phylogenetic tree, which synapomorphies unite the pigeon and the lizard?

The Apocynaceae is a (taxonomic unit) _______ of plants.

Stickleback fish evolve changes in body armor whenever they move from freshwater to marine settings (and vice versa).Such changes occur often and repeatedly and are due to changes at a few genes.Would the body armor changes be useful in constructing phylogenies of sticklebacks? Explain.