13
45) If intelligent extraterrestrials visited Earth 475 million years ago, and then again 300 million years
ago (at the close of the Carboniferous period), what trends would they have noticed in Earth’s terrestrial
vegetation over this period?
1. a trend from dominant gametophytes to dominant sporophytes
2. a trend from sporangia borne on modified leaves (sporophylls) to sporangia borne on stalks (seta)
3. a trend from no true leaves, to microphylls, to megaphylls
4. a trend from soil-surface-hugging plants to “overtopping” plants
5. a trend toward increased lignification of conducting systems
A) 1 and 3
B) 3, 4, and 5
C) 1, 2, 4, and 5
D) 1, 3, 4, and 5
E) 2, 3, 4, and 5
46) If you were faced with the choice of eliminating all mutualistic symbioses involving plants and other
organisms (besides humans), with the goal being to preserve the most plant biomass, which of the
following would you save from elimination?
A) the dispersal of seeds in or on animals
B) the dispersal of male gametophytes by animals
C) plants harboring nitrogen-fixing bacteria
D) associations between soil fungi and roots or rhizoids
47) During glacial periods in the early evolution of land plants, which of the following would have been
a beneficial adaptation regarding the number of stomata per unit surface area, and what accounts for it?
A) increased numbers of stomata, to maximize absorption of increasing levels of atmospheric CO2
B) increased numbers of stomata, to maximize ability to absorb low levels of atmospheric CO2
C) decreased numbers of stomata, to retain CO2 produced by the chloroplasts
D) decreased numbers of stomata, to maximize absorption of low levels of atmospheric CO2
48) What is thought to be the correct sequence of the following events during the Carboniferous period?
1. vascular plants become more prevalent
2. megaphylls with large surface areas become more prevalent
3. atmospheric CO2 levels decline by a factor of five
4. global cooling occurs, leading to widespread glaciations
A) 1, 2 ,3, 4
B) 2, 1, 3, 4
C) 2, 1, 4, 3
D) 1, 2, 4, 3
E) 3, 4, 1, 2
The next question is based on the following description and Figure 29.1, which is the same as Figure
29.10 in the textbook.
Art Questions
Researchers tested nitrogen loss from soil where the moss Polytrichum was growing, and compared it to
soil from which Polytrichum had been removed. The data are presented below.
Figure 29.1
49) Loss of soil nitrogen via “gaseous emission” was found to be negligible. Rather, most loss of soil
nitrogen was due to water erosion of the soil. Which of these hypotheses is least likely to account for the
observed results?
A) If rhizoids had helped stabilize the soil, then less erosion and less loss of nitrogen would occur.
B) If protonemata had absorbed, and stored, nitrogen from the soil, then they would have reduced loss of
nitrogen by erosion.
C) If the overlying mat of gametophores had slowed the entry of water into the soil, then it would have
reduced water’s ability to erode the soil and carry away its nitrogen.
D) If sporophyte stomata had absorbed nitrogen from the soil, then they would have reduced loss of
nitrogen by erosion.
15
Refer to the following information to answer the next few questions.
Researchers decided to test the hypothesis that if the 2-m tall Polytrichum gametophyte-sporophyte
plants had acted as a physical buffer, then they would have reduced water’s ability to erode the soil and
carry away its nitrogen. They began with four equal-sized areas where Polytrichum mosses grew to a
height of 2 m above the soil surface. One of the four areas was not modified. In the second area, the
mosses were trimmed to a height of 1 m above the soil surface. In the third area, the mosses were
trimmed to a height of 0.5 m above the soil surface. In the fourth area, the mosses were trimmed all the
way to the ground, leaving only the rhizoids. Water, simulating rainfall, was then added in a controlled
fashion to all plots over the course of one year. Figure 29.2 presents four graphs that depict potential
results of this experiment.
Figure 29.2
50) Which graph of soil nitrogen loss over time in Figure 29.2 most strongly supports the hypothesis that
if the 2-m tall Polytrichum gametophyte-sporophyte plants had acted as a physical buffer, then they
would have reduced water’s ability to erode the soil and carry away its nitrogen?
A) A
B) B
C) C
D) D
16
51) If the actual results most closely resembled those in Figure 29.2(A), then a further question arising
from these data is: “Do the Polytrichum rhizoids have to be alive in order to reduce soil nitrogen loss, or
do dead rhizoids have the same effect?” Arrange the following steps in the correct sequence to test this
hypothesis.
1. Add metabolic poison to the soil of the experimental plot of mosses.
2. Apply water equally to the experimental and control plots.
3. Measure initial soil nitrogen contents of control and experimental plots.
4. Determine nitrogen loss from soil of control and experimental plots.
5. Establish two identical plots of Polytrichum mosses; one as a control, the other as the experimental
treatment.
A) 5 → 1 → 3 → 2 → 4
B) 5 → 2 → 3 → 1 → 4
C) 5 → 3 → 1 → 2 → 4
D) 4 → 5 → 1 → 3 → 2
E) 5 → 3 → 2 → 1 → 4
52) Which of these potential results of applying a metabolic poison to the rhizoids of Polytrichum
should interfere the least with the ability to draw valid conclusions from this experiment?
A) If, upon dying, the rhizoids leak nitrogenous compounds into the soil before final nitrogen content is
measured.
B) If, upon dying, decomposition of the rhizoids introduces nitrogenous compounds to the soil before
final nitrogen content is measured.
C) If the metabolic poison is hydrogen cyanide (HCN) or sodium azide (NaN3), and much of the poison
remains in the soil.
D) If the metabolic poison acts against the mitochondria of the rhizoid cells.
E) If the metabolic poison absorbs nitrogen and strongly adheres to soil particles, acting as a sort of glue.
53) Why should we expect the soil’s nitrogen not to be contained solely within the rhizoids of the
Polytrichum mosses?
A) Rhizoids are associated with fungi that inhibit mineral transfer from soil to rhizoids.
B) Rhizoids are not absorptive structures.
C) Rhizoids consist of single, tubular cells or of filaments of cells.
D) Rhizoids lack direct attachment to the moss sporophytes.
17
54) The 2-m height attainable by Polytrichum moss is at the upper end of the size range reached by
mosses. What accounts for the relative tallness of Polytrichum?
A) the cuticle that is found along the ridges of “leaves”
B) “leaves” that are more than one cell layer thick
C) high humidity of surrounding air which provides support against gravity
D) reduced size, mass, and persistence of the sporophytes which allows gametophores to grow taller
E) the presence of conducting tissues in the “stem”
Figure 29.3
55) What is true of the phylogenetic tree in Figure 29.3?
1. It depicts uncertainty about whether the bryophytes or the vascular plants evolved first.
2. It is hypothetical.
3. It includes polytomies.
4. It shows that ferns (phylum Pterophyta) are the closest living relatives to the seed plants.
5. It indicates that seeds are a shared ancestral character of all vascular plants.
A) 1 and 2
B) 2 and 3
C) 1, 2, and 3
D) 1, 2, and 4
E) 2, 3, and 5
56) The resolution of the relationships indicated by dashed lines in Figure 29.3 will most probably come
from
A) more whole-genome analyses of extant (living) species.
B) more-detailed analyses of the morphologies of extant species.
C) the discovery of more fossils of extinct taxa from the time of seed-plant origins.
D) more-detailed analyses of the life cycles of extant species.
E) more molecular analyses of the types and structures of photosynthetic pigments present in extant
species.
18
57) Which of the following should be most helpful in distinguishing the clades depicted on the tree in
Figure 29.3 from each other?
A) the types of conducting tissues that are present
B) the types of photosynthetic pigments that are present
C) the details of reproduction
D) the concentration of stomata present on leaves of the saprophyte generation
E) whether it is the sporophyte generation or the gametophyte generation that is dominant
Scenario Questions
The next few questions are based on the following description.
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.
58) This student has probably found a(n)
A) immature pine tree.
B) bryophyte sporophyte.
C) fern sporophyte.
D) horsetail gametophyte.
E) lycophyte sporophyte.
59) Besides oil, what other chemical should be detected in substantial amounts upon chemical analysis
of these small spheres?
A) sporopollenins
B) phenolics
C) waxes
D) lignins
E) terpenes
60) This organism probably belongs to the same phylum as the
A) ferns, horsetails, and whisk ferns.
B) club mosses, quillworts, and spike mosses.
C) mosses, hornworts, and liverworts.
D) conifers.
E) charophytes.
19
61) 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.
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.
62) What feature of both true mosses and ferns makes it most surprising that they can survive for many
generations in dry deserts?
A) flagellated sperm
B) lack of vascular tissues
C) lack of true roots
D) lack of cuticle
E) a gametophyte generation that is dominant
63) Which of the following features is most important in order for true mosses and ferns to survive and
reproduce in the desert?
A) that the sporophytes occupy only permanently shady, north-facing habitats
B) that the sporophytes hug the ground, growing no taller than a couple of inches
C) either that their gametophytes grow close together, or that they be hermaphroditic
D) that the sporophytes have highly lignified vascular tissues
20
64) Which of the following characteristics is (are) possessed in common by true mosses, ferns, and spike
mosses, and therefore becomes useless at helping to determine to which of these groups flower of stone
belongs?
1. a sporophyte generation that is dominant
2. true leaves and roots
3. flagellated sperm
4. strobili
5. alternation of generations
A) 5 only
B) 1 and 5
C) 2 and 3
D) 3 and 5
E) 2, 4, and 5
65) Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures.
Each cone-like structure emits spores of two different sizes. Based on this information, which of the
following can be properly inferred about flower of stone?
1. It is heterosporous.
2. It is a fern.
3. The cone-like structures are sori.
4. It is a lycophyte.
5. It has separate male and female gametophytes.
A) 1 and 5
B) 2 and 3
C) 1, 2, and 3
D) 1, 4, and 5
E) 1, 2, 3, and 5
66) Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures.
Each cone-like structure emits spores of two different sizes. Consequently, which of the following is the
closest living relative of flower of stone?
A) true moss
B) club moss
C) hornwort
D) liverwort
E) fern
67) Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures.
Each cone-like structure emits spores of two different sizes. Consequently, flower of stone should be
expected to possess which other characteristics?
1. a gametophyte generation that is dominant
2. lignified vascular tissues
3. microphylls
4. filamentous rhizoids, but not true roots
5. spores that are diploid when mature
A) 1 and 2
B) 1 and 5
C) 2 and 3
D) 2, 3, and 4
E) 3, 4, and 5
68) 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
22
End-of-Chapter Questions
The following questions are from the end-of–chapter “Test Your Understanding” section in Chapter 29
of the textbook.
69) Which of the following is not evidence that charophytes are the closest algal relatives of plants?
A) similar sperm structure
B) the presence of chloroplasts
C) similarities in cell wall formation during cell division
D) genetic similarities in chloroplasts
E) similarities in proteins that synthesize cellulose
70) 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) formation of a cell plate during cytokinesis
D) sexual reproduction
E) alternation of multicellular generations
71) In plants, which of the following are produced by meiosis?
A) haploid sporophytes
B) haploid gametes
C) diploid gametes
D) haploid spores
E) diploid spores
72) Microphylls are found in which plant group?
A) mosses
B) liverworts
C) lycophytes
D) ferns
E) hornworts
23
73) Which of the following is a land plant that has flagellated sperm and a sporophyte-dominated life
cycle?
A) fern
B) moss
C) liverwort
D) charophyte
E) hornwort
74) Suppose an efficient conducting system evolved in a moss that could transport water and other
materials as high as a tall tree. Which of the following statements about “trees” of such a species would
not be true?
A) Fertilization would probably be more difficult.
B) Spore dispersal distances would probably increase.
C) Females could produce only one archegonium.
D) Unless its body parts were strengthened, such a “tree” would probably flop over.
E) Individuals would probably compete more effectively for access to light.