Biol122 Quiz 3
Which of the following statements is always TRUE about sister taxa on a phylogenetic tree?
Sister taxa always share a most recent common ancestor that is not shared with any other taxon on the phylogeny.
Why might a phylogeny based only on molecular data show a different pattern of relationships than a phylogeny of the same taxa that is based only on morphological traits? (Select all that apply.)
Some highly conserved genetic sequences can result in unrelated species appearing closely related in a molecular phylogeny, and not reflect the same pattern as the morphologic phylogeny. Gene sequence changes may not result in morphological changes.
When visiting Hawaii on vacation, a tourist notices that there are many different species of birds that look similar to one another, but are distinct in their ecology and in the morphology (beak size and shape) that helps make them successful in different habitats on the island. The tourist supposes they are closely related and result from an adaptive radiation. Which of the following statements would provide the STRONGEST evidence they are the result of an adaptive radiation?
The phylogeny of the birds shows a single common ancestor for the group.
The remarkable fossil of the "fishapod," Tiktaalik, which lived about 375 million years ago, is a beautiful example of an intermediate form, having the attributes of both fish (scales, fins) and tetrapods (a flat head, mobile neck). The presence of Tiktaalik and other fossils of other organisms that lived around the same time shows clear evidence that tetrapods were derived from fish, implying, that the grouping "fish" is paraphyletic. Imagine now that there was no fossil record. Would it still be possible to determine whether or not "fish" is paraphyletic?
Yes, because a phylogeny can be constructed using morphological and molecular characters of modern fish and tetrapods.
According to the phylogenetic tree shown in Figure 1.16, the primate MOST closely related to humans is the:
chimpanzee
Seals and penguins both have streamlined body forms that allow them to move through water efficiently. This similarity in body shape is MOST likely the result of:
convergent evolution
A population of rodents, called population A, lived together in harmony on a large landmass until one group of the population dispersed to a nearby island. Two million years later, the island population is split into two smaller, equal-sized populations when a river formed across the middle of the island. Now two new species have evolved on the island, A1 and A2. They have replaced the population from which they were derived. Which represents the phylogeny of the populations discussed in this scenario?
diagram K
What types of data can be used to construct phylogenies such as the one below?
molecular data, fossil evidence, and anatomical, physiological, and developmental studies of extant species
Which phylogenetic group includes all descendants of a common ancestor and only the descendants of that ancestor?
monophyletic
The specific types of homologies used to develop phylogenies are shared derived characters or:
synapomorphies
Examine the following table of characters in four different species of flower. Based on the matrix, which tree represents the MOST parsimonious explanation of relatedness among these species?
phylogeny 2
The same intron was sequenced from five different taxa (taxa A-E) whose evolutionary relationships are disputed. The data matrix given shows six variable sites (1-6, left column) in the DNA sequences obtained from each of the five species. Taxon A serves as the outgroup for this analysis.
phylogeny II