BIO 105: Exam 2

Based upon the figure below, the phylogenetic tree _____. 1 - depicts uncertainty about whether the bryophytes or the vascular plants evolved first 2 - depicts an evolutionary hypothesis 3 - includes polytomies 4 - shows that members of the phylum Pterophyta are the closest living relatives to the seed plants 5 - indicates that seeds are a shared ancestral character of all vascular plants

2 and 3

Which of these habitats is likely to harbor the most recently diverged species?

A1

The Panama Canal was completed in 1914, and its depth is about fifty feet. After 1914, snapping shrimp species from which habitats should be most likely to form hybrids as the result of the canal?

A1 and B1

In which habitat should one find snapping shrimp most closely related to shrimp that live in habitat A4?

B4

Which tree depicts the animals as the basal taxon?

Both B and C

If organisms A, B, and C belong to the same class but to different orders and if organisms C, D, and E 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?

D and E

Refer to the figure above. Which of the following forms a monophyletic group?

E, F and G

Which tree depicts the closest relationship between ascomycetes and microsporidians?

I

Which of the following would be useful in creating a phylogenetic tree of a taxon? I) morphological data from fossil species II) genetic sequences from living species III) behavioral data from living species

I, II, and III

By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?

It is part of a monophyletic group that also includes G. intestinalis

A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or temperature. Such environments are thought to have been much more common on the primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago. Which of the following is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged?

On a phylogenetic tree whose branch lengths are proportional to the amount of genetic change, the branches of the extremophiles should be shorter than the non-extremophilic archaeans.

According to the phylogenetic tree in the figure above, G. intestinalis(refer the selection area) constitutes a _____ group

Paraphyletic

Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with _____.

Phylogenies

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information?

Postzygotic isolation exists between the two frog species.

Based on this tree, which statement is correct?

Salamanders are as closely related to the goats as humans.

Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?

Their winter habitat has no bearing on their degree of reproductive isolation.

Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

They have been geographically isolated from each other for a longer time.

Given that phylogenies are based on shared derived characteristics, which of the following traits is useful in generating a phylogeny of species W, X, Y, and Z?

Trait 2

Applying the principle of parsimony to the trait "ability to fly," which of the two phylogenetic trees below is better?

Tree 1

In a comparison of birds and mammals, having four limbs is _____.

a shared ancestral character

The largest unit within which gene flow can readily occur is _____.

a species

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of _____.

allopatric speciation

According to the biological species concept, for speciation to occur, _____.

at least one gene, affecting at least one phenotypic trait, which can result in reproductive isolation, must change

Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact?

behavioral reproductive isolating mechanism

In hybrid zones where reinforcement is occurring, we should see a decline in ________.

gene flow between distinct gene pools

If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be _____.

homoplasy

A crucial photosynthetic gene of the cyanobacterium that gave rise to the chromatophore is called psaE. This gene is present in the nuclear genome of the cercozoan, but is not in the genome of the chromatophore. This is evidence of _____.

horizontal gene transfer from bacterium to eukaryotes

We know the streamlined bodies shown in the figure above are examples of homoplasy. If the following groups also had streamlined bodies, which of the groupings would give the most support to this body type being homologous?

lizards, pterosaurs, dinosaurs, birds, synapsids, monotremes, marsupials, rodents, and primates

You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?

morphological

The peppered moth provides a well-known example of natural selection. The light-colored form of the moth was predominant in England before the Industrial Revolution. In the mid-nineteenth century, a dark-colored form appeared. The difference is produced by a dominant allele of one gene. By about 1900, approximately 90% of the moths around industrial areas were dark colored, whereas light-colored moths were still abundant elsewhere. Apparently, birds could readily find the light moths against the soot-darkened background in industrial areas and, therefore, were eating more light moths. Recently, use of cleaner fuels has greatly reduced soot in the landscape, and the dark-colored moths have been disappearing. Should the two forms of moths be considered separate species?

no

Assuming chimps and gorillas are humans' closest relatives, i) removing humans from the great ape clade and placing them in a different clade and ii) excluding their most common ancestor would have the combined effect of making the phylogenetic tree of the great apes _____.

polyphyletic

Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

polyphyletic taxa and paraphyletic taxa

Two species of tree frogs that live sympatrically in the northeastern United States differ in ploidy: Hyla chrysoscelis is diploid, and Hyla versicolor is tetraploid. The frogs are identical in appearance, but their mating calls, which females use to find mates, differ. Which difference most likely evolved first?

polyploidy

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). If the molecular data best reflect the evolutionary history of these two groups, then the morphological similarities of these two species is most likely due to _____.

possession of analogous (convergent) traits

The best classification system is that which most closely _____.

reflects evolutionary history

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?

sympatric speciation; habitat differentiation

About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. (N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629-32.) Refer to the paragraph about the formation of the Isthmus of Panama. The sister populations on opposite sides of the isthmus are true species under which species concept?

the morphological species, biological species, and phylogenetic species concepts

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

to serve as an outgroup