Download Answers to End-of-Chapter Questions – Brooker et al ARIS site

Answers to End-of-Chapter Questions – Brooker et al ARIS site
Chapter 31
Test Yourself Questions
1. What feature must be present in order for a plant to produce wood?
a.
b.
c.
d.
e.
a type of conducting system in which vascular bundles occur in a ring around pith
a eustele
a vascular cambium
all of the above
none of the above
Answer: d. In order to produce wood, a plant must have a ring-shaped vascular system (known as a
eustele) and a vascular cambium.
2. What is the correct order of evolution for these critical adaptations?
a.
b.
c.
d.
e.
embryos, vascular tissue, wood, seeds, flowers
vascular tissue, embryos, wood, flowers, seeds
vascular tissue, wood, seeds, embryos, flowers
wood, seeds, embryos, flowers, vascular tissue
seeds, vascular tissue, wood, embryos, flowers
Answer: a. The correct order of evolution of key plant adaptations is: embryos, vascular tissue, wood,
seeds, and flowers.
3. How long have gymnosperms been important members of plant communities?
a.
b.
c.
d.
e.
10,000 years, since the dawn of agriculture
100,000 years
300,000 years
65 million years, since the K/T event
300 million years, during the Coal Age
Answer: c. Gymnosperms have been important components of plant communities for the past 300 million
years.
4. What similar features do gnetophytes and angiosperms possess that differ from other modern seed
plants?
a. Gnetophytes and angiosperms both produce flagellate sperm.
b. Gnetophytes and angiosperms both produce flowers.
c. Gnetophytes and angiosperms both produce tracheids, but not vessels, in their vascular
tissues.
d. Gnetophytes and angiosperms both produce fruits.
e. None of the above.
Answer: e. Gnetophytes and angiosperms are similar in lacking archegonia (female gametangia) and in
producing vessels. By contrast, other modern seed plants produce archegonia and lack vessels.
5. Which part of a flower receives pollen from the wind or a pollinating animal?
a. perianth
b.
c.
d.
e.
stigma
filament
peduncle
ovary
Answer: b. The stigma of the pistil is a receptive surface for pollen.
6. The primary function of a fruit is to:
a.
b.
c.
d.
e.
provide food for the developing seed.
provide food for the developing seedling.
disperse pollen.
disperse seeds.
none of the above.
Answer: d. The primary function of a fruit is to disperse seeds by means of wind, water, or animals.
7. What are some ways in which flowers have diversified?
a.
b.
c.
d.
e.
color
symmetry
fusion of organs
aggregation into inflorescences
all of the above
Answer: e. Flowers have diversified by changing color and symmetry, by fusing organs in various ways, and
by grouping flowers to form inflorescences.
8. Flowers of the genus Fuchsia produce deep pink to red flowers that dangle from plants, produce nectar
in floral tubes, and have no scent. Based on these features, which animal is most likely to be a coevolved
pollinator?
a.
b.
c.
d.
e.
bee
bat
hummingbird
butterfly
moth
Answer: c. Among the pollinators listed, hummingbirds are most likely to have coevolved with the plant
genus Fuchsia.
9. Which type of plant secondary metabolite is best known for antioxidant properties of human foods such
as blueberries, tea, and grape juice?
a.
b.
c.
d.
e.
alkaloids
cannabinoids
carotenoids
phenolics
terpenoids
Answer: d. Among the secondary metabolites listed, phenolics, particularly the forms known as flavonoids,
are best known for their antioxidant properties.
10. What features of domesticated grain crops might differ from those of wild ancestors?
a. the degree to which ears shatter, allowing for seed dispersal
b.
c.
d.
e.
grain size
the number of grains per ear
the softness and edibility of grains
all of the above
Answer: e. Domesticated grain crop plants differ from wild relatives (which model wild ancestors of
domesticated crops) in ear shattering, grain size, grains per ear, and grain softness and edibility.
Conceptual Questions
1. Explain why humans should not consume food products made from cycads.
Answer: Cycads typically produce toxins that protect against herbivory. At least some cycads harbor
cyanobacterial symbionts that are known to produce an unusual amino acid (BMAA) that is associated with
dementia in humans.
2. Explain why fruits such as apples, strawberries, and cherries are attractive and harmless food for
humans.
Answer: Apple, strawberry, and cherry plants coevolved with animals that use the fleshy, sweet portion of
the fruits as food, and excrete the seeds, thereby dispersing them. Humans have sensory systems similar
to those of the target animals and are likewise are attracted by the same colors, odors, and tastes.
3. Is a sunflower really a flower?
Answer: No, a sunflower is an inflorescence, a group of flowers.
Experimental Questions
1. Why did the investigators in the Feature Investigation 31.23 obtain nearly a hundred Cannabis fruit
samples from around the world?
Answer: They wanted to increase their chances of finding as many species as possible.
2. Why did Hillig and Mahlberg grow plants in a greenhouse before conducting the cannabinoid analysis?
Answer: They wanted to reduce possible impact of environmental variation on the ratio of cannabinoids
produced.
3. Why did Hillig and Mahlberg collect samples from the leaves growing nearest the flowers.
Answer: Although cannabinoids are produced in glandular hairs that cover the plant surface, these
compounds are most abundant on leaves near the flowers. Collecting such leaves reduces the chances
that compounds might be missed by the analysis.
Collaborative Questions
1. Where in the world would you have to travel to find wild plants representing all of the gymnosperm phyla,
including the three types of gnetophytes?
Answer: You would have to travel to the tropics or subtropics to find wild cycads and Gnetum, to China to
find Ginkgo closest to the wild condition, to desert regions of North America to find wild Ephedra, to deserts
of Namibia in southwestern Africa to find Welwitschia mirabilis. You should be able to locate diverse wild
conifers in temperate and northern forests around the world.
2. How would you go about trying to solve what Darwin called “an abominable mystery,” the identity of the
seed plant group that was ancestral to the flowering plants?
Answer: You could sequence as many genes as possible, perhaps even whole genomes, from diverse
living gymnosperms and compare them to the genes or genomes of early-diverging flowering plants. But
even this mighty effort might not help very much if angiosperms’ closest seed plant relatives are extinct.
You could organize a major fossil hunting effort with collaborators from around the world who sample rocks
about 150 million years old or older. The group could look for previously unknown phyla of seed plants
and/or carefully compare known fossils of appropriate age for clues to the origin of flowering plants.