Chapters 13 and 16

Question 1

Coevolution in predator-prey interactions can not lead to

Answer 1

Ecological character displacement

Question 2

You are in an area famous for the presence for cuckoo birds, and you notice a mother bird kicking eggs out of its nest. What is the most likely explanation?

Answer 2

The bird has recognized an attempt at brood parasitism and is removing the threat

Question 3

The Red Queen hypothesis is often used to explain

Answer 3

Coevolution in parasite-host interactions

Question 4

What behavior is most likely to disrupt the mutualistic interaction as described?

Answer 4

When parasites are scarce, mutualistic cleaner wrasse will cheat and instead bite the scales off of larger fish at a cleaning station

Question 5

Interactions between which species are not likely to lead to coevolution?

Answer 5

The finches Geospiza fuliginosa and G. fortis

Question 6

Refer to the figure. The organisms shown here are all “archosaurs.” The first six are “dinosaurs,” but Crocodiles are not. The node that represents the most recent common ancestor of all archosaurs is _______, and the node that represents the most recent common ancestor of all dinosaurs is

Answer 6

D; C

Question 7

Refer to the graph. The data in the graph suggest that

Answer 7

Different types of data are most informative at different timescales

Question 8

You examine long sequences from four genes in three closely related species, species A, B, and C. Genes 1–3 all suggest A and B are each other’s closest relative, but gene 4 suggests that A and C are. Assuming that the “true” phylogeny is that A and B are sister species, which explanation is least likely to account for the different relationship shown by the fourth sequence?

Answer 8

The sequence similarity of the fourth gene between A and C is a result of homoplasy

Question 9

Which complication to phylogenetic inference is most likely to be widespread in a group of species that have undergone an evolutionary radiation?

Answer 9

Incomplete lineage sorting

Question 10

Mammals, like humans and apes, have five digits on their fore and hind limbs. Modern horses have one. How might you reconstruct the ancestral state of mammal toe number?

Answer 10

Either Investigate the number of toes for mammals and use parsimony to deduce the ancestral state, or Investigate the number of toes for an outgroup that is closely related to mammals, for example reptiles or amphibians

Question 11

The figure shows relationships among major groups of vertebrates. According to the data in the figure,

Answer 11

Mammals are monophyletic for both phylogenies

Question 12

Historically, humans were placed into the taxonomic family Hominidae, and the great apes (orangutan, gorilla, bonobo, and chimpanzee) were placed into Pongidae. Modern taxonomists now place humans, along with the other great apes, into a single family, Hominidae. Use the phylogeny in the figure to identify the fact that led to this revision

Answer 12

Chimps and bonobos are more closely related to humans than they are to the other great apes

Question 13

Refer to the figure showing a phylogenetic tree of some snakes and lizards. According to the figure, which statement is true?

Answer 13

If we created a new taxon consisting of the venomous SNAKES (shown in figure as group V), it would be paraphyletic

Question 14

Stickleback fish found in lakes rapidly evolve a low armor plate morphology when compared to marine populations. Analysis of the gene responsible shows that populations with low plating form one clade and marine populations form another. However, gene trees formed with other genes show that the low plating phenotype probably evolved independently multiple times. How have scientists resolved these contradictory gene trees?

Answer 14

A single origin of the low plating gene in the oceanic population that remained at a low frequency until lakes were colonized. Then the gene independently became fixed in each

Question 15

Refer to the figure. Imagine you have a phylogeny that you are sure is correct that includes five species. You examine a gene sequence and discover that species A and E differ by 100 base pairs, species B and E differ by 101 base pairs, species C and E differ by 180 base pairs, and species D and E differ by 183 base pairs. What would you say is the most likely pattern of evolutionary rates among these species?

Answer 15

Rates of evolution increased for species C and D after they diverged from their common ancestor with species B

Question 16

How might phylogenetic analyses of predators and prey, or of parasites and hosts, help determine whether or not there has been an evolutionary arms race?

Answer 16

Assuming that the predator-prey interaction is coevolving, phylogenetic analyses would show similar branch lengths and similar patterns around the same time for both predator and prey species. Branch lengths and patterns indicate the possible divergences in the reciprocal, adaptive construction and cospeciation of the predator and prey species in order to continue the evolutionary arms race. Perhaps through the synchronized branching of the species and it’s closest relatives would provide clues to a coevolutionary interaction such that the predator and prey are evolving simultaneously to one another in order to maintain its species’ survival. Additionally, if either or both species of the predator and prey branch had come to an abrupt end, this would suggest that there could have been an evolutionary arms race that occurred, but the involved specie(s) were unable to overcome its counterpart or environment thereby leading to extinction.

Question 17

Suppose that, among related host species that carry related symbionts, the relationship is mutualistic in some pairs and parasitic in others. How would you determine (a) which relationship is mutualistic and which is parasitic, (b) what the direction of evolutionary change has been, and (c) whether the change from one to the other kind of interaction has been a result of evolutionary change in the symbiont, in the host, or both?

Answer 17

a) Mutualistic relationships should show the host and symbiont to have interactions that mutually benefit both species. Parasitic relationships should show either one of the host and symbiont species to dominate over the counterpart species in the interaction. That one species benefits at the expense of the other.
b) The direction of evolutionary change could be determined by comparing the host and symbiont with/without the presence of its interacting counterpart relative to the time it takes for the symbiotic interaction to occur and diverge through cospeciation. This can be inferred with a phylogenetic tree.
c) Interaction change from evolutionary change in either the host, symbiont, or both can be determined by comparing the phylogenies of the host and symbiont to determine the primary specie(s) undergoing evolutionary change. This can be further analyzed with the difference in lifetime fitness of the two species in the both the mutualistic and parasitic interaction forms.