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A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea.
She is the first fly to arrive on this island and the only fly to arrive in this way.
Thousands of years later, her numerous offspring occupy the island, but none of them
resembles her. There are, instead, several species, each of which eats only a certain type
of food. None of the species can fly and their balancing organs (halteres) are now used
in courtship displays. The male members of each species bear modified halteres that are
unique in appearance to their species. Females bear vestigial halteres. The ranges of all
of the daughter species overlap.
Which of these fly organs, as they exist in the description above, best illustrates an
exaptation?
A) vestigial halteres
B) halteres
C) mouthparts
D) eggs
A cell is considered to be differentiated when it _____.
A) replicates by the process of mitosis
B) loses connections to the surrounding cells
C) produces proteins specific to a particular cell type
D) appears to be different from the surrounding cells
Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the
offspring to self-pollinate to produce an F2 generation. The results were as follows:
6022 yellow and 2001 green (8023 total). The allele for green seeds has what
relationship to the allele for yellow seeds?
A) dominant
B) incomplete dominant
C) recessive
D) codominant
Tetrodotoxin blocks voltage-gated sodium channels and ouabain blocks
sodium-potassium pumps. If you added both tetrodotoxin and ouabain to a solution
containing neural tissue, what responses would you expect?
A) immediate loss of resting potential
B) immediate loss of action potential with gradual loss of resting potential
C) slow decrease of resting potential and action potential amplitudes
D) No effect; the substances counteract each other.
The solutions in the two arms of this U-tube are separated by a membrane that is
permeable to water and glucose but not to sucrose. Side A is half-filled with a solution
of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose.
Initially, the liquid levels on both sides are equal.
Refer t o the figure. Initially, in terms of tonicity, the solution in side A with respect to
the solution in side B is _____.
A) hypotonic
B) isotonic
C) saturated
D) hypertonic
Which of the following statements is true about buffer solutions?
A) They maintain a constant pH when bases are added to them but not when acids are
added to them.
B) They maintain a constant pH when acids are added to them but not when bases are
added to them.
C) They fluctuate in pH when either acids or bases are added to them.
D) They maintain a relatively constant pH when either acids or bases are added to them.
If a lung were to be found in a mollusc, where would it be located?
A) mantle cavity
B) incurrent siphon
C) visceral mass
D) excurrent siphon
Among the following choices, the most concentrated urine is excreted by _____.
A) frogs
B) kangaroo rats
C) humans
D) freshwater bass
Which of the following would prevent allergic attacks?
A) blocking the attachment of the IgE antibodies to the mast cells
B) blocking the antigenic determinants of the IgM antibodies
C) reducing the number of helper T cells in the body
D) reducing the number of cytotoxic cells
When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the
extinction of species _____.
A) occurs, but that there is no evolution
B) and the evolution of species both occur
C) and the evolution of species do not occur
D) does not occur, but evolution does occur
Comb jellies may not be the most familiar animal to you, but they are critical in the
food chain because they make up a significant portion of the planktonic biomass. Their
feeding strategy is predatory and involves adhesives or mucus on their tentacles or other
body parts. What feeding tactic do these animals use?
A) suspension feeder
B) fluid feeder
C) deposit feeder
D) food-mass feeder
Which extant chordates are postulated to be most like the earliest chordates in
appearance?
A) lancelets
B) adult tunicates
C) amphibians
D) chondrichthyans
Conifers and pines both have needlelike leaves, with the adaptive advantage of _____.
A) increased surface area, increasing photosynthesis
B) increased surface area, increasing gas exchange
C) decreased surface area, reducing gas exchange
D) decreased surface area, reducing water loss
The chloroplasts of land plants are thought to have been derived according to which
evolutionary sequence?
A) cyanobacteria → green algae → land plants
B) cyanobacteria → green algae → fungi → land plants
C) red algae → brown algae → green algae → land plants
D) cyanobacteria → red algae → green algae → land plants
Genomic imprinting is generally due to the addition of methyl (-CH3) groups to C
nucleotides and chemical histone changes to silence a given gene. If this depends on the
sex of the parent who transmits the gene, which of the following must be true?
A) Genes required for early development stages must not be imprinted.
B) Methylation of this kind must occur more in males than in females.
C) Methylation must be reversible in ovarian and testicular cells.
D) The imprints are transmitted only to gamete-producing cells.
Refer to the figure. If the carbon atom of each of the incoming CO2 molecules is
labeled with a radioactive isotope of carbon, which organic molecules will be
radioactively labeled after one cycle?
A) C only
B) B, C, D, and E
C) C, D, and E only
D) B and C only
Which of the following statements best summarizes the acid-growth hypothesis in an
actively growing shoot?
A) Auxin stimulates proton pumps in the plasma membrane and tonoplast.
B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and
makes the walls more flexible.
C) Auxins and gibberellins together act as a lubricant to help stretch cellulose
microfibrils.
D) Auxins activate aquaporins that increase turgor pressure in the cells.
If you are hiking through the desert for several days, one would pack which of the
following to ensure proper hydration?
A) a drink with a combination of water and electrolytes
B) caffeinated beverages
C) bottled water kept at room temperature
D) bottled water that had been frozen to ensure that it would be as cold as possible
Which of the following conditions is the most likely indicator of a population in an
extinction vortex?
A) The species in question is found only in small, stable pockets of its former range.
B) The effective population size of the species falls below 1000.
C) Genetic measurements indicate a loss of genetic variation over time.
D) The population is connected only by corridors.
The smallest cell structure that would most likely be visible with a standard (not
super-resolution) research-grade light microscope is a _____.
A) mitochondrion
B) microtubule
C) ribosome
D) microfilament
A small number of birds arrive on an island from a neighboring larger island. This small
population begins to adapt to the new food plants available on the island, and their
beaks begin to change. About twice a year, one or two more birds from the neighboring
island arrive. These new arrivals _____.
A) speed up the process of speciation
B) tend to promote adaptation to the new food plants
C) tend to retard adaptation to the new food plants
D) represent a colonizing event
Magnesium has an atomic number of 12. What is the most stable charge for a
magnesium ion?
A) a +1 charge
B) a +2 charge
C) a -1 charge
D) a -2 charge
Fragments of DNA have been extracted from the remnants of extinct woolly
mammoths, amplified, and sequenced. These can now be used to _____.
A) introduce certain mammoth traits into relatives, such as elephants
B) clone live woolly mammoths
C) appreciate the reasons why mammoths went extinct
D) better understand the evolutionary relationships among members of related taxa
CD4 and CD8 are _____.
A) proteins secreted by antigen-presenting cells
B) receptors present on the surface of natural killer cells
C) molecules present on the surface of T cells where they interact with major
histocompatability (MHC) molecules
D) molecules on the surface of antigen-presenting cells where they enhance B cell
activity
Which kind of metabolic poison would most directly interfere with glycolysis?
A) an agent that reacts with oxygen and depletes its concentration in the cell
B) an agent that binds to pyruvate and inactivates it
C) an agent that closely mimics the structure of glucose but is not metabolized
D) an agent that reacts with NADH and oxidizes it to NAD+
Based on the idea that fungi have pores between their cell walls, which allow cytoplasm
to move from one end of the mycelium to the other, which of the following hypotheses
is the most plausible?
A) If a single mycorrhizal fungus formed symbiotic associations with more than one
tree, carbon could travel from one plant to another.
B) Parasitic fungi steal nutrients from their hosts.
C) Predatory fungi capture their prey by encircling them with hyphae, and the flowing
of the cytoplasm through the pores helps the hyphae to move around the prey.
D) Fungi function as part of the global carbon cycle not only by converting carbon from
one form to another, but by physically moving it from one location to another.
Hair cells in the vertebrate ear are responsible for transducing sound pressure waves.
Ion channels in the hair cell membrane open when _____.
A) a chemical ligand binds to the ion channel
B) light is absorbed by a molecule in the membrane
C) the cell membrane reaches a threshold voltage
D) the membrane is distorted mechanically
You are given four test tubes, each containing an unknown protist, and your task is to
read the following description and match these four protists to the correct test tube.
When light, especially red and blue light, is shone on the tubes, oxygen bubbles
accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates
the presence of a chemical that is toxic to fish and humans. Chemical analysis of test
tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of
organisms in test tubes 1, 3, and 4 reveals the presence of permanent,
membrane-bounded sacs just under the plasma membrane. Microscopic analysis of
organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic
analysis of the contents in test tube 4 reveals the presence of one large nucleus and one
small nucleus in each organism.
Test tube 4 contains _____.
A) Paramecium
B) Pfiesteria (dinoflagellate)
C) Entamoeba
D) Plasmodium
Abstract:
Increased radiative forcing is an inevitable part of global climate change, yet little is
known of its potential effects on the energy fluxes in natural ecosystems. To simulate
the conditions of global warming, we exposed peat monoliths (depth, 0.6 cm; surface
area, 2.1 m2) from a bog and fen in northern Minnesota, USA, to three infrared (IR)
loading (ambient, +45, and +90 W m-2) and three water table (-16, -20, and -29 cm in
bog and -1, -10 and -18 cm in fen) treatments, each replicated in three mesocosm plots.
Net radiation (Rn) and soil energy fluxes at the top, bottom, and sides of the mesocosms
were measured in 1999, five years after the treatments had begun. Soil heat flux (G)
increased proportionately with IR loading, comprising about 3%-8% of Rn. In the fen,
the effect of IR loading on G was modulated by water table depth, whereas in the bog, it
was not. Energy dissipation from the mesocosms occurred mainly via vertical exchange
with air, as well as the deeper soil layers through the bottom of the mesocosms, whereas
lateral fluxes were 10- to 20-fold smaller and independent of IR loading and water table
depth. The exchange with deeper soil layers was sensitive to water table depth, in
contrast to G, which responded primarily to IR loading. The qualitative responses in the
bog and fen were similar, but the fen displayed wider seasonal variations and greater
extremes in soil energy fluxes. The differences of G in the bog and fen are attributed to
differences in the reflectance in the long waveband as a function of vegetation type,
whereas the differences in soil heat storage may also depend on different soil properties
and different water table depth at comparable treatments. These data suggest that the
ecosystem-dependent controls over soil energy fluxes may provide an important
constraint on biotic response to climate change.
Copyright 2004 Springer-Verlag (A. Noormets et al. 2004. The effects of infrared
loading and water table on soil energy fluxes in northern peatlands. Ecosystems
7:573-582.)
The Noormets et al. study (2004) shows that there was an ecosystem-specific control
over soil energy fluxes, and this constrained the biotic response to climate change. How
do you think radiative heat would affect the water table in a wetland versus a temperate
forest?
A) The wetland would likely absorb less heat than the temperate forest and, therefore,
not significantly change water table depth.
B) The wetland would likely absorb more heat than the temperate forest and
significantly change water table depth.
C) The temperate forest would likely absorb more heat than the wetland and
significantly change water table depth.
D) Both areas would absorb similar amounts of radiative heat and, therefore, affect the
water table equally.
Ionotropic receptors found at synapses are operated via _____.
A) ligand-gated ion channels
B) electrical synapses
C) inhibitory, but not excitatory, synapses
D) excitatory, but not inhibitory, synapses
Which of the following statements is a correct distinction between autotrophs and
heterotrophs?
A) Cellular respiration is unique to heterotrophs.
B) Only heterotrophs have mitochondria.
C) Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and
other nutrients that are inorganic.
D) Only heterotrophs require oxygen.
A population of squirrels on an island has a carrying capacity of 350 individuals. If the
maximum rate of increase is 1.0 per individual per year and the population size is 275,
determine the population growth rate (Round to the nearest whole number).
A) 59 squirrels per year
B) -34 squirrels per year
C) 75 squirrels per year
D) 15 squirrels per year
Refer to the following graph of an action potential to answer the question(s) below.
The cell is not hyperpolarized; however, repolarization is in progress, as the sodium
channels are closing or closed, and many potassium channels have opened at label
_____.
A) B
B) C
C) D
D) E
What is the main force by which most of the water within xylem vessels moves toward
the top of a tree?
A) active transport of ions into the stele
B) evaporation of water through stoma
C) the force of root pressure
D) osmosis in the root
The following experiment is used for the corresponding question(s).
A researcher discovered a species of moth that lays its eggs on oak trees. Eggs are laid
at two distinct times of the year: early in spring when the oak trees are flowering and in
midsummer when flowering is past. Caterpillars from eggs that hatch in spring feed on
oak flowers and look like oak flowers. But caterpillars that hatch in summer feed on
oak leaves and look like oak twigs.
How does the same population of moths produce such different-looking caterpillars on
the same trees? To answer this question, the biologist caught many female moths from
the same population and collected their eggs. He put at least one egg from each female
into eight identical cups. The eggs hatched, and at least two larvae from each female
were maintained in one of the four temperature and light conditions listed below.
In each of the four environments, one of the caterpillars was fed oak flowers, the other
oak leaves. Thus, there were a total of eight treatment groups (4 environments x2 diets).
Refer to the accompanying figure. Recall that eggs from the same female were exposed
to each of the eight treatments used. This aspect of the experimental design tested
which of the following hypotheses?
A) The longer day lengths of summer trigger the development of twig-like caterpillars.
B) Differences in air pressure, due to elevation, trigger the development of different
types of caterpillars.
C) Differences in diet trigger the development of different types of caterpillars.
D) The differences are genetic. A female will either produce all flowerlike caterpillars
or all twig-like caterpillars.
