Use the following information to answer the question(s) below.
In 1983 a population of dark-eyed junco birds became established on the campus of the
University of California, San Diego (UCSD), which is located many miles from the
junco’s normal habitat in the mixed-coniferous temperate forests in the mountains.
Juncos have white outer tail feathers that the males display during aggressive
interactions and during courtship displays. Males with more white in their tail are more
likely to win aggressive interactions, and females prefer to mate with males with more
white in their tails. Females have less white in their tails than do males, and display it
less often. (Pamela J. Yeh. 2004. Rapid evolution of a sexually selected trait following
population establishment in a novel habitat. Evolution 58[1]:166-74.)
Refer to the paragraph on dark-eyed junco birds. The UCSD campus male junco
population tails are about 36% white, whereas the tails of males from nearby mountain
populations are about 40-45% white. The founding stock of UCSD birds was likely
from the nearby mountain populations because some of those birds overwinter on the
UCSD campus each year. Population sizes on the UCSD campus have been reasonably
large, and there are significant habitat differences between the UCSD campus and the
mountain coniferous forests; UCSD campus has a more open environment (making
birds more visible) and a lower junco density (decreasing intraspecific competition)
than that in the mountain forests. Given this information, which of the following
evolutionary mechanisms do you think is most likely responsible for the difference
between the UCSD and mountain populations?
A) natural selection
B) genetic drift
C) gene flow
D) mutation
What is the primary function of stems?
A) Facilitation of gas exchange
B) Water absorption and movement
C) Maximization of photosynthesis by leaves
D) Reproduction
The sea slug Pteraeolidia ianthina (P. ianthina) can harbor living dinoflagellates
(photosynthetic protists) in its skin. These endosymbiotic dinoflagellates reproduce
quickly enough to maintain their populations. Low populations do not affect the sea
slugs very much, but high populations (> 5 x 105 cells/mg of sea slug protein) can
promote sea slug survival.
Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates.
If the dinoflagellate-containing sea slug P. ianthina preys on coral animals, then it
would be LEAST surprising to find that _____.
A) P. ianthina has no tolerance to the toxin in the nematocysts of its prey
B) P. ianthina can locate its coral prey by chemicals released into the water by corals
C) the coral prey harbor dinoflagellates in their tissues
D) the coral prey transform themselves into medusas to flee from approaching P.
ianthina
What does the graph in the figure above tell you about the definition of a keystone
species?
A) A keystone species has little interaction with other species in an environment.
B) Removing a keystone species from the community drastically reduces diversity.
C) Adding a keystone species to the community will make it more diverse.
D) Removing a keystone species from the community will eventually allow for the
invasion of a new species.
Choose a pair that correctly associates the mechanism for osmoregulation or nitrogen
removal with the appropriate animal.
A) metanephridium flatworm
B) Malpighian tubule frog
C) flame bulb snake
D) exchange across the body surface marine invertebrate
Which feature seen in chytrids supports the hypothesis that they diverged earliest in
fungal evolution?
A) the absence of chitin within the cell wall
B) coenocytic hyphae
C) flagellated spores
D) parasitic lifestyle
Which of the following sequences is most likely to be cut by a restriction enzyme?
A) AATTCT
TTAAGA
B) AATATT
TTATAA
C) AAAATT
TTTTAA
D) ACTACT
TGATGA
Compared with a smaller cell, a larger cell of the same shape has _____.
A) less surface area
B) less surface area per unit of volume
C) a smaller average distance between its mitochondria and the external source of
oxygen
D) a smaller cytoplasm-to-nucleus ratio
Homeotic genes contain a homeobox sequence that is highly conserved among very
diverse species. The homeobox is the code for that domain of a protein that binds to
DNA in a regulatory developmental process. Therefore, you would expect that _____.
A) homeotic genes are selectively expressed as an organism develops
B) homeoboxes cannot be expressed in nonhomeotic genes
C) homeotic genes in apes and humans are very different
D) all organisms must have homeotic genes
The R-group, or side chain, of the amino acid serine is -CH2-OH. The R-group, or side
chain, of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find
these amino acids in a globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular
protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular
protein.
C) Serine and leucine would both be in the interior of the globular protein.
D) Serine and leucine would both be on the exterior of the globular protein.
A woman who has blood type A positive has a daughter who is type O positive and a
son who is type B negative. Rh positive is a trait that shows simple dominance over Rh
negative. Which of the following is a possible phenotype for the father?
A) A negative
B) O negative
C) B positive
D) AB negative
Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what
characteristic, leading to which phenomenon?
A) mass extinctions, leading to bottleneck effect
B) major evolutionary innovations, leading to rafting to nearby continents
C) a variety of empty ecological niches, leading to adaptive radiation
D) adaptive radiation, leading to founder effect
Which of the following is characteristic of a steroid hormone action?
A) protein phosphorylation
B) cell-surface receptor binding
C) internal receptor binding
D) second messenger activation
A certain kind of snail can have a right-handed direction of shell coiling (DD or Dd) or
left-handed coiling (dd). However, if direction of coiling is due to a protein deposited
by the mother in the egg cytoplasm, then a Dd egg-producing snail and a dd
sperm-producing snail will have offspring of which genotype(s) and phenotype(s)?
A) 1/2 Dd:1/2 dd; all right-coiling
B) all Dd; all right-coiling
C) 1/2 Dd:1/2 dd; half right-coiling and half left-coiling
D) all Dd; half right-coiling and half left-coiling
Giardia intestinalis can cause disease in several different mammalian species, including
humans. Giardia organisms (G. intestinalis) that infect humans are similar
morphologically to those that infect other mammals; thus they have been considered a
single species. However, G. intestinalis has been divided into different subgroups based
on their host and a few other characteristics.
In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups
actually constitute different species. The following phylogenetic tree was constructed
from the sequence comparison of rRNA from several subgroups of G. intestinalis and a
few other morphologically distinct species of Giardia. The researchers concluded that
the subgroups of Giardia are sufficiently different from one another genetically that
they could be considered different species. (T. Monis et al. 1999. Molecular systematics
of the parasitic protozoan Giardia intestinalis. Mol. Biol. Evol. 16[9]:1135-44.)
By examining the phylogenetic tree diagrammed in the figure above, what conclusion
can you draw about the species G. microti?
A) It evolved before G. intestinalis.
B) It is more closely related to G. muris than to G. intestinalis.
C) It should not be labeled a species distinct from G. intestinalis.
D) It is part of a monophyletic group that also includes G. intestinalis.
A hypothetical bacterium swims among human intestinal contents until it finds a
suitable location on the intestinal lining. It adheres to the intestinal lining using a
feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal
matter from a human in whose intestine this bacterium lives can spread the bacterium,
even after being mixed with water and boiled. The bacterium is not susceptible to the
penicillin family of antibiotics. It contains no plasmids and relatively little
peptidoglycan.
What should be true of the cell wall of this bacterium?
A) Its innermost layer is composed of a phospholipid bilayer.
B) After it has been subjected to Gram staining, the cell should remain purple.
C) It has an outer membrane of lipopolysaccharide.
D) It is mostly composed of a complex, cross-linked polysaccharide.
Plasmogamy can directly result in which of the following?
1. cells with a single haploid nucleus
2. heterokaryotic cells
3. dikaryotic cells
4. cells with two diploid nuclei
A) 1 or 3
B) 2 or 3
C) 2 or 4
D) 3 or 4
Based on the figure above, showing fetal (A) and adult (B) oxygen-hemoglobin
saturation curves, which of the following conclusions is true?
A) The mother binds oxygen with greater affinity than the fetus.
B) Adult saturation occurs at lower partial pressures of oxygen than fetal saturation
does.
C) At 50 percent saturation, fetal blood will have a higher affinity for oxygen than adult
blood will.
D) As the partial pressure of oxygen increases, adult hemoglobin approaches saturation
faster than fetal hemoglobin does.
If you were using cladistics to build a phylogenetic tree of cats, which of the following
would be the best outgroup?
A) lion
B) domestic cat
C) wolf
D) leopard
Dll is a gene known to direct limb development in the fruit fly. Researchers studying
this gene have found that it is also expressed in developing appendages in animals from
many other phyla, supporting the hypothesis that all animal appendages may be
homologous. However, suppose researchers looking at Dll activity had instead found
the results shown in the figure above. These results suggest instead that _____.
A) Dll is not actually involved in appendage development
B) appendages evolved separately in protostomes and deuterostomes
C) appendages coevolved with segmentation
D) all animal appendages are homologous
If the experimental population of E. coli lacks an F factor or F plasmid, and if
bacteriophages are excluded from the bacterial cultures, then beneficial mutations might
be transmitted horizontally to other E. coli cells via _____.
A) sex pili
B) transduction
C) conjugation
D) transformation
Once researchers identified DNA as the unit of inheritance, they asked how information
was transferred from the DNA in the nucleus to the site of protein synthesis in the
cytoplasm. What is the mechanism of information transfer in eukarotes?
A) DNA from a single gene is replicated and transferred to the cytoplasm, where it
serves as a template for protein synthesis.
B) Messenger RNA is transcribed from a single gene and transfers information from the
DNA in the nucleus to the cytoplasm, where protein synthesis takes place.
C) Proteins transfer information from the nucleus to the ribosome, where protein
synthesis takes place.
D) Transfer RNA takes information from DNA directly to a ribosome, where protein
synthesis takes place.
One of the fundamental processes by which memories are stored and learning takes
place _____.
A) is related to changes in the degree of myelination of axons
B) results in an increase in the diameter of axons
C) results in a shift from aerobic to anaerobic respiration in neurons
D) involves two types of glutamate receptors
Which pair of terms most accurately describes life history traits for a stable population
of wolves?
A) semelparous; r-selected
B) semelparous; K-selected
C) iteroparous; r-selected
D) iteroparous; K-selected
We should care about loss in biodiversity in other species because of _____.
I) potential loss of medicines and other products yet undiscovered from threatened
species
II) potential loss of genes, some of which may code for proteins useful to humans
III) the risk to global ecological stability
A) only I
B) only II
C) only II and III
D) I, II, and III
Why do histones bind tightly to DNA?
A) Histones are positively charged, and DNA is negatively charged.
B) Histones are negatively charged, and DNA is positively charged.
C) Both histones and DNA are strongly hydrophobic.
D) Histones are covalently linked to the DNA.
The partial negative charge in a molecule of water occurs because _____.
A) the oxygen atom donates an electron to each of the hydrogen atoms
B) the electrons shared between the oxygen and hydrogen atoms spend more time
around the oxygen atom nucleus than around the hydrogen atom nucleus
C) the oxygen atom has two pairs of electrons in its valence shell that are not
neutralized by hydrogen atoms
D) one of the hydrogen atoms donates an electron to the oxygen atom
The mitosome of Giardia has no DNA within it. If it did contain DNA, then what
predictions should we be able to make about its DNA?
1. It is linear.
2. It is circular.
3. It has many introns.
4. It has few introns.
5. It is not associated with histone proteins.
6. It is complexed with histone proteins.
A) 1, 3, and 5
B) 1, 4, and 5
C) 2, 3, and 6
D) 2, 4, and 5
Some botanists argue that the entire plant should be considered as a single unit rather
than a composite of many individual cells. Which of the following cellular structures
best supports this view?
A) cell wall
B) cell membrane
C) vacuole
D) plasmodesmata
CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can
do this because they _____.
A) fix CO2 into organic acids during the night
B) fix CO2 into sugars in the bundle-sheath cells
C) fix CO2 into pyruvate in the mesophyll cells
D) use photosystem I and photosystem II at night
The restriction enzymes of bacteria protect the bacteria from successful attack by
bacteriophages, whose genomes can be degraded by the restriction enzymes. The
bacterial genomes are not vulnerable to these restriction enzymes because bacterial
DNA is methylated. This situation selects for bacteriophages whose genomes are also
methylated. As new strains of resistant bacteriophages become more prevalent, this in
turn selects for bacteria whose genomes are not methylated and whose restriction
enzymes instead degrade methylated DNA. The outcome of the conflict between
bacteria and bacteriophage at any point in time results from _____.
A) frequency-dependent selection
B) evolutionary imbalance
C) heterozygote advantage
D) neutral variation