A biology student hiking in a forest happens upon an erect, 15-cm-tall plant that bears microphylls and a strobilus at its tallest point. When disturbed, the cone emits a dense cloud of brownish dust. A pocket magnifying glass reveals the dust to be composed of tiny spheres with a high oil content.
This student has probably found a(n)
A) immature pine tree.
B) bryophyte sporophyte.
C) fern sporophyte.
D) horsetail gametophyte.
E) Lycophyte sporophyte
E
A biology student hiking in a forest happens upon an erect, 15-cm-tall plant that bears microphylls and a strobilus at its tallest point. When disturbed, the cone emits a dense cloud of brownish dust. A pocket magnifying glass reveals the dust to be composed of tiny spheres with a high oil content.
A dissection of the interior of this organism's stem should reveal
A) lignified vascular tissues.
B) cuticle.
C)
gametangia.
D) that it is composed of only a single, long
cell.
E) a relatively high proportion of dead, water-filled cells.
A
The cycads, a mostly tropical phylum of gymnosperms, evolved about
300 million years ago and were dominant forms during the Age of the
Dinosaurs. Though their sperm are flagellated, their ovules are
pollinated by beetles. These beetles get nutrition (they eat pollen)
and shelter from the microsporophylls. Upon visiting megasporophylls,
the beetles transfer pollen to the exposed ovules. In cycads, pollen
cones and seed cones are borne on different plants. Cycads synthesize
neurotoxins, especially in the seeds, that are effective against most
animals, including humans.
If the beetles survive
by consuming cycad pollen, then whether the beetles should be
considered mutualists with, or parasites of, the cycads depends
upon
A) the extent to which their overall activities
affect cycad reproduction.
B) the extent to which the beetles are
affected by the neurotoxins.
C) the extent to which the beetles
damage the cycad flowers.
D) the distance the beetles must travel
between cycad microsporophylls and cycad megasporophylls.
A
The Brazil nut tree, Bertholletia excels (n = 17), is native to
tropical rain forests of South America. It is a hardwood tree that can
grow to over 50 meters, is a source of high-quality lumber, and is a
favorite nesting site for harpy eagles. As the rainy season ends,
tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to
the forest floor. About $50 million worth of nuts are harvested each
year. Scientists have discovered that the pale yellow,
self-incompatible flowers of Brazil nut trees admit only female orchid
bees as pollinators.
People who attempted to plant Brazil
nuts in hopes of establishing plantations of Brazil nut trees played
roles most similar to those of
A) agoutis.
B) orchid
bees.
C) pollen tubes.
D) harpy eagles.
A
The Brazil nut tree, Bertholletia excels (n = 17), is native to
tropical rain forests of South America. It is a hardwood tree that can
grow to over 50 meters, is a source of high-quality lumber, and is a
favorite nesting site for harpy eagles. As the rainy season ends,
tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to
the forest floor. About $50 million worth of nuts are harvested each
year. Scientists have discovered that the pale yellow,
self-incompatible flowers of Brazil nut trees admit only female orchid
bees as pollinators.
Entrepreneurs attempted, but failed,
to harvest nuts from plantations grown in Southeast Asia. Attempts to
grow Brazil nut trees in South American plantations also failed. In
both cases, the trees grew vigorously, produced healthy flowers in
profusion, but set no fruit. Consequently, what is the likely
source of the problem?
A) poor sporophyte
viability
B) poor sporophyte fertility
C) failure to
produce fertile ovules
D) failure to produce pollen
E)
pollination failure
E
The Brazil nut tree, Bertholletia excels (n = 17), is native to
tropical rain forests of South America. It is a hardwood tree that can
grow to over 50 meters, is a source of high-quality lumber, and is a
favorite nesting site for harpy eagles. As the rainy season ends,
tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to
the forest floor. About $50 million worth of nuts are harvested each
year. Scientists have discovered that the pale yellow,
self-incompatible flowers of Brazil nut trees admit only female orchid
bees as pollinators.
The harpy eagle, Harpia harpyja, is
the largest, most powerful raptor in the Americas. It nests only in
trees taller than 25 meters. It is a "sloth specialist," but
will also take agouti. Thus, if these eagles capture too many
agoutis from a particular locale, they might contribute to their own
demise by
A) having too many offspring.
B) increasing habitat
loss.
C) decreasing atmospheric CO2.
D) increasing the
number of sloths.
B
For several decades now, amphibian species worldwide have been in
decline. A significant proportion of the decline seems to be due to
the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd).
Chytrid sporangia reside within the epidermal cells of infected
animals, animals that consequently show areas of sloughed skin. They
can also be lethargic, which is expressed through failure to hide and
failure to flee. The infection cycle typically takes four to five
days, at the end of which zoospores are released from sporangia into
the environment. In some amphibian species, mortality rates approach
100%; other species seem able to survive the infection.
Sexual reproduction has not been observed in Bd. A Bd
sporangium initially contains a single, haploid cell. Which of the
following processes must be involved in generating the multiple
zoospores eventually produced by each sporangium?
1. S phase
2. cytokinesis
3. mitosis
4.
meiosis
A) 1 and 2
B) 1 and 3
C) 2 and
3
D) 1, 2, and 3
E) 1, 2, and 4
D
The Brazil nut tree, Bertholletia excels (n = 17), is native to tropical rain forests of South America. It is a hardwood tree that can grow to over 50 meters, is a source of high-quality lumber, and is a favorite nesting site for harpy eagles. As the rainy season ends, tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to the forest floor. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow, self-incompatible flowers of Brazil nut trees admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animals with teeth strong enough to crack the hard wall of Brazil nut fruits. It typically eats some of the seeds, buries others, and leaves still others inside the fruit, which moisture can then enter. The uneaten seeds may subsequently germinate.
The agouti is most directly involved with the Brazil nut tree's dispersal of
A) male gametophytes.
B) female gametophytes.
C)
sporophyte embryos.
D) sporophyte megaspores.
E) female gametes.
C
Big Bend National Park in Texas is mostly Chihuahuan desert, where
rainfall averages about 10 inches per year. Yet, it is not uncommon
when hiking in this bone-dry desert to encounter mosses and ferns. One
such plant is called "flower of stone." It is not a
flowering plant, nor does it produce seeds. Under arid conditions, its
leaflike structures curl up. However, when it rains, it unfurls its
leaves, which form a bright green rosette on the desert floor.
Consequently, it is sometimes called the "resurrection
plant." At first glance, it could be a fern, a true moss, or a
spike moss.
In which combination of locations
would one who is searching for the gametophytes of flower of stone
have the best chance of finding them?
1.
moist soil
2. underground, nourished there by symbiotic
fungi
3. south- or west-facing slopes
4. permanently shady
places
5. far from any flower of stone sporophytes
A) 1 only
B) 1 and 2
C) 1, 2, and 4
D) 1, 2, and
5
E) 1, 3, 4, and 5
C
For several decades now, amphibian species worldwide have been in
decline. A significant proportion of the decline seems to be due to
the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd).
Chytrid sporangia reside within the epidermal cells of infected
animals, animals that consequently show areas of sloughed skin. They
can also be lethargic, which is expressed through failure to hide and
failure to flee. The infection cycle typically takes four to five
days, at the end of which zoospores are released from sporangia into
the environment. In some amphibian species, mortality rates approach
100%; other species seem able to survive the infection.
The fact that infection by Bd causes lethargy in many
infected amphibians can have what effect on efforts to accurately
census the numbers of dead or dying amphibians at a particular
time, in a particular habitat?
A) It can cause
underestimation, due to infected amphibians preferring to seek out
refuges relative to uninfected amphibians.
B) It can cause
underestimation, due to increased predation on, and removal of,
infected amphibians relative to uninfected amphibians.
C) It can
cause overestimation, because infected frogs should be more readily
observable to human census-takers than should uninfected
amphibians.
D) All three of the above statements are
plausible.
E) Two of the above statements are plausible.
E
Diploid nuclei of the ascomycete, Neurospora crassa, contain 14
chromosomes. A single diploid cell in an ascus will undergo one round
of meiosis, followed in each of the daughter cells by one round of
mitosis, producing a total of eight ascospores.
If a single, diploid G₂ nucleus in an ascus contains 400
nanograms (ng) of DNA, then a single ascospore nucleus of this
species should contain how much DNA (ng), carried on how many
chromosomes?
A) 100, carried on 7
chromosomes
B) 100, carried on 14 chromosomes
C) 200,
carried on 7 chromosomes
D) 200, carried on 14
chromosomes
E) 400, carried on 14 chromosomes
A
Diploid nuclei of the ascomycete, Neurospora crassa, contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores.
What is the ploidy of a single mature ascospore?
A) monoploid (/haploid)
B) diploid
C) triploid
D)
tetraploid
E) polyploid
A
The cycads, a mostly tropical phylum of gymnosperms, evolved about
300 million years ago and were dominant forms during the Age of the
Dinosaurs. Though their sperm are flagellated, their ovules are
pollinated by beetles. These beetles get nutrition (they eat pollen)
and shelter from the microsporophylls. Upon visiting megasporophylls,
the beetles transfer pollen to the exposed ovules. In cycads, pollen
cones and seed cones are borne on different plants. Cycads synthesize
neurotoxins, especially in the seeds, that are effective against most
animals, including humans.
Which feature of
cycads makes them similar to many angiosperms?
1. They have exposed ovules.
2. They have flagellated
sperm.
3. They are pollinated by animals.
A) 1
only
B) 2 only
C) 3 only
D) 2 and 3
E) 1, 2, and 3
C
For several decades now, amphibian species worldwide have been in
decline. A significant proportion of the decline seems to be due to
the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd).
Chytrid sporangia reside within the epidermal cells of infected
animals, animals that consequently show areas of sloughed skin. They
can also be lethargic, which is expressed through failure to hide and
failure to flee. The infection cycle typically takes four to five
days, at the end of which zoospores are released from sporangia into
the environment. In some amphibian species, mortality rates approach
100%; other species seem able to survive the infection.
When adult amphibian skin harbors populations of the
bacterium, Janthinobacterium lividum (Jl), chytrid infection seems
to be inhibited. Which of the following represents the best
experimental design for conclusively determining whether this
inhibition is real?
A) Inoculate uninfected amphibians with Jl, and determine whether
the amphibians continue to remain uninfected by chytrids.
B)
Inoculate infected amphibians with Jl, and determine whether the
amphibians recover from infection by chytrids.
C) Take infected
amphibians and assign them to two populations. Leave one population
alone; inoculate the other with Jl. Measure the rate at which
infection proceeds in both populations.
D) Take infected
amphibians and assign them to two populations. Inoculate one
population with a high dose of Jl; inoculate the other with a low dose
of Jl. Measure the survival frequency in both populations.
C
The Brazil nut tree, Bertholletia excels (n = 17), is native to
tropical rain forests of South America. It is a hardwood tree that can
grow to over 50 meters, is a source of high-quality lumber, and is a
favorite nesting site for harpy eagles. As the rainy season ends,
tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to
the forest floor. About $50 million worth of nuts are harvested each
year. Scientists have discovered that the pale yellow,
self-incompatible flowers of Brazil nut trees admit only female orchid
bees as pollinators.
The same bees that pollinate
the flowers of the Brazil nut trees pollinate orchids, which are
epiphytes (in other words, plants that grow on other plants);
however, orchids cannot grow on Brazil nut trees. These observations explain
A) the coevolution of Brazil nut trees and orchids.
B) why
Brazil nut trees do not set fruit in plantations.
C) why male
orchid bees do not pollinate Brazil nut tree flowers.
D) why male
orchid bees are smaller than female orchid bees.
E) the
importance of orchid and Brazil nut tree flowers for the production of
orchid bee honey.
B
The cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were dominant forms during the Age of the Dinosaurs. Though their sperm are flagellated, their ovules are pollinated by beetles. These beetles get nutrition (they eat pollen) and shelter from the microsporophylls. Upon visiting megasporophylls, the beetles transfer pollen to the exposed ovules. In cycads, pollen cones and seed cones are borne on different plants. Cycads synthesize neurotoxins, especially in the seeds, that are effective against most animals, including humans.
On the Pacific island of Guam, large herbivorous bats called "flying foxes" commonly feed on cycad seeds, a potent source of neurotoxins. The flying foxes do not visit male cones. Consequently, what should be true?
A) The flying foxes are attracted to cycad fruit, and eat the
enclosed seeds only by accident.
B) Flying foxes are highly
susceptible to the effects of the neurotoxins.
C) The flying
foxes assist the beetles as important pollinating agents of the
cycads.
D) Flying foxes can be dispersal agents of cycad seeds if
the seeds sometimes get swallowed whole (in other words, without
getting chewed).
D
The cycads, a mostly tropical phylum of gymnosperms, evolved about
300 million years ago and were dominant forms during the Age of the
Dinosaurs. Though their sperm are flagellated, their ovules are
pollinated by beetles. These beetles get nutrition (they eat pollen)
and shelter from the microsporophylls. Upon visiting megasporophylls,
the beetles transfer pollen to the exposed ovules. In cycads, pollen
cones and seed cones are borne on different plants. Cycads synthesize
neurotoxins, especially in the seeds, that are effective against most
animals, including humans.
61) Which feature of cycads distinguishes them from most other gymnosperms?
1. They have exposed ovules.
2. They have flagellated
sperm.
3. They are pollinated by animals.
A) 1 only
B) 2 only
C) 3 only
D) 2 and 3
E)
1, 2, and 3
D
For several decades now, amphibian species worldwide have been in
decline. A significant proportion of the decline seems to be due to
the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd).
Chytrid sporangia reside within the epidermal cells of infected
animals, animals that consequently show areas of sloughed skin. They
can also be lethargic, which is expressed through failure to hide and
failure to flee. The infection cycle typically takes four to five
days, at the end of which zoospores are released from sporangia into
the environment. In some amphibian species, mortality rates approach
100%; other species seem able to survive the infection.
A researcher took water in which a Jl population had been
thriving, filtered the water to remove all bacterial cells, and then
applied the water to the skins of adult amphibians to see if there
would subsequently be a reduced infection rate by Bd when frog skins
were inoculated with Bd. For which of the following hypotheses is
the procedure described a potential test?
A) the hypothesis that a toxin secreted by Jl cells kills Bd cells
when both are present together on frog skin
B) the hypothesis
that Jl cells infect and kill Bd cells when both are present together
on frog skin
C) the hypothesis that Jl outcompetes Bd when both
are present together on a frog's skin
D) the hypothesis that the
presence of Jl on frog skin causes a skin reaction that prevents
attachment by Bd cells
A
In onions (Allium), cells of the sporophyte have 16 chromosomes
within each nucleus. Match the number of chromosomes present in each
of the following onion tissues.
How many chromosomes should be in an embryo nucleus?
A) 4
B) 8
C) 16
D) 24
E) 32
C
All fungi are
A) symbiotic
B) heterotrophic
C) flagellated
D) decomposers
B
Which of the following characteristics of plants is absent in their closest relatives, the charophyte algae?
A) chlorophyll b
B) cellulose in cell walls
C) multicellularity
D) alternation of generations
D
Among the organisms listed here, which are thought to be the closest relatives of fungi?
A) slime molds
B) vascular plants
C) animals
D) mosses
C
The adaptive advantage associated with the filamentous nature of fungal mycelia is primary related to
A) the ability to parasitize other organisms
B) avoiding sexual reproduction until the environment changes
C) the potential to inhabit almost all terrestrial habitats
D) an extensive surface area well suited for invasive growth and absorptive nutrition
D