Ch. 38 Mastering bio
What adaptations should one expect of the seed coats of angiosperm species whose seeds are dispersed by frugivorous (fruit-eating) animals, as opposed to angiosperm species whose seeds are dispersed by other means? 1. The exterior of the seed coat should have barbs or hooks. 2. The seed coat should contain secondary compounds that irritate the lining of the animal's mouth. 3. The seed coat should be able to withstand low pHs. 4. The seed coat, upon its complete digestion, should provide vitamins or nutrients to animals. 5. The seed coat should be resistant to the animals' digestive enzymes.
3 and 5
In a typical angiosperm, what is the sequence of structures encountered by the tip of a growing pollen tube on its way to the egg? 1. micropyle 2. style 3. ovary 4. stigma 1 → 3 → 4 → 2 4 →? 2 → 3 → 1 3 → 2 → 4 → 1 4 → 3 → 2 → 1
4 →? 2 → 3 → 1
Arrange the following structures from largest to smallest, assuming that they belong to two generations of the same angiosperm. 1. ovary 2. ovule 3. egg 4. carpel 5. embryo sac 5, 1, 4, 2, 3 4, 2, 1, 5, 3 5, 4, 3, 1, 2 4, 1, 2, 5, 3
4, 1, 2, 5, 3
Use the following information to answer the question(s) below. 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 tall, 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. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal 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 now enter. The uneaten seeds may subsequently germinate. If a female orchid bee has just left a Brazil nut tree with nectar in her stomach, and if she visits another flower on a different Brazil nut tree, what is the sequence in which the following events should occur? 1. double fertilization 2. pollen tube emerges from pollen grain 3. pollen tube enters micropyle 4. pollination
4, 2, 3, 1
f an ovary contains 50 ovules, what is the minimum number of pollen grains that must land to form 50 mature seeds? 100 50 500 25
50
Suppose that 100 pollen grains land on a stigma, and 50 mature seeds are formed in the fruit. What does this indicate about the pollination process and success? 50% success: 100 pollen grains grew to 50 ovules, and double fertilization occurred. 50% success: 50 sperm fertilized 50 eggs, and 50 sperm fused with 100 polar nuclei. 50% success: evidently, only 50 sperm pollinated 50 anthers. 50% success: 50 sperm fertilized 50 eggs, and 50 sperm fused with 50 polar nuclei.
50% success: 50 sperm fertilized 50 eggs, and 50 sperm fused with 100 polar nuclei.
Use the following information to answer the question(s) below. 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 tall, 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. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal 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 now enter. The uneaten seeds may subsequently germinate. Animals that consume Brazil nuts derive nutrition mostly from tissue whose nuclei have how many chromosomes?
51
Among plants known as legumes (beans, peas, alfalfa, clover, for example) the seeds are contained in a fruit that is itself called a legume, better known as a pod. Upon opening such pods, it is commonly observed that some ovules have become mature seeds, whereas other ovules have not. Thus, which of the following statements is (are) true? 1. The flowers that gave rise to such pods were not pollinated. 2. Pollen tubes did not enter all of the ovules in such pods. 3. There was apparently not enough endosperm to distribute to all of the ovules in such pods. 4. The ovules that failed to develop into seeds were derived from sterile floral parts. 5. Fruit can develop, even if all ovules within have not been fertilized.
2 and 5
Which of the following is a potential advantage of introducing apomixis into hybrid crop species? They would benefit from positive mutations in their DNA. All of the desirable traits of the cultivar would be passed on to offspring. Cultivars would be better able to cope with a rapidly changing environment. They would have a larger potential genome than inbred crops.
All of the desirable traits of the cultivar would be passed on to offspring.
What is typically the result of double fertilization in angiosperms? Both a diploid embryo and triploid endosperm are formed. Two embryos develop in every seed. The endosperm develops into a diploid nutrient tissue. A triploid zygote is formed.
Both a diploid embryo and triploid endosperm are formed.
Which of the following is a scientific concern related to creating genetically modified crops? Genetically modified crops cannot survive without the addition of great amounts of fertilizer to the soil. The monetary costs of growing genetically modified plants are significantly greater than traditional breeding techniques. Genetically modified plants are less stable and may revert back to parental genotypes. Herbicide resistance may spread to weedy species.
Herbicide resistance may spread to weedy species.
Which of these activities is part of the development of crop plants from wild relatives? I) people planting seeds of the plants with the characteristic wanted II) people making observations of desired plant characteristics III) people eating products from only the plants with desired characteristics IV) people developing several varieties of crops from a wild relative I and II I, III, and IV I, II, and IV I and IV
I, II, and IV
Which of the following occur during the formation of an embryo from a zygote in angiosperms? I) The root and shoot systems emerge from the seed. II) Basal cells form a connection between the parent plant and the developing embryo. III) Meiosis produces a mass of cells that become the young embryo. IV) Cells differentiate to form the basic plant tissue types. V) The early root-shoot axis is formed. II, III, IV, and V II, IV, and V I, II, and III III, IV, and V
II, IV, and V
Which of the following is a true statement about asexual reproduction in plants? Cloning, although achieved in animals, has not been demonstrated in plants. Reproduction of plants by cloning may be either sexual or asexual. Making cuttings of ornamental plants is a form of fragmentation. Clones of plants do not occur naturally.
Making cuttings of ornamental plants is a form of fragmentation.
A researcher has developed two stains for use with seed plants. One stains sporophyte tissue blue; the other stains gametophyte tissue red. If the researcher exposes pollen grains to both stains, and then rinses away the excess stain, what should occur? The pollen grains will have red interiors and blue exteriors. The pollen grains will have blue interiors and red exteriors. The pollen grains will be pure blue. The pollen grains will be pure red.
The pollen grains will have red interiors and blue exteriors.
Cottonwood, aspen, and willow trees have beige flowers, with no petals, that appear before the tree's leaves are out in the spring; and they are dioecious. What does this indicate about these trees? Their pollen is dispersed by wind. Early emerging insects are probably the pollinators. The trees are self-pollinating. Their insect pollinators are specialists.
Their pollen is dispersed by wind.
Which of these events occurs first in seed germination? Water is taken up. Mitochondria multiply and provide energy for growth processes. Oxygen is produced and proteins are synthesized. Cell division occurs in the embryo and growth starts.
Water is taken up
The black dots that cover strawberries are actually individual fruits. The fleshy and tasty portion of a strawberry derives from the receptacle of a flower with many separate carpels. Therefore, a strawberry is _____. both a multiple fruit and an aggregate fruit both an aggregate fruit and an accessory fruit a simple fruit with many seeds both a multiple fruit and an accessory fruit
both an aggregate fruit and an accessory fruit
Use the following information to answer the question(s) below. 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 tall, 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. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal 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 now enter. The uneaten seeds may subsequently germinate. Orchid bees are to Brazil nut trees as ________ are to pine trees. breezes seed-eating birds squirrels rain droplets
breezes
"Golden Rice" _____. is resistant to various herbicides, making it practical to weed rice fields with those herbicides includes bacterial genes that produce a toxin that reduces damage from insect pests contains daffodil genes that increase vitamin A content produces larger, golden grains that increase crop yields
contains daffodil genes that increase vitamin A content
While looking at a flower in your garden, you notice that it has carpels with very long styles, and stamens with very short filaments. This plant is most likely to reproduce by _____. selfing cross-pollination asexual reproduction
cross-pollination
Which of the following types of plants are incapable of self-pollination? insect-pollinated wind-pollinated dioecious monoecious
dioecious
Unripe fruits protect seeds from predation and early germination. What is the major function of ripe fruits? attracting pollinators dispersing seed keeping the seed hydrated before germination releasing nutrients to seeds
dispersing seed
In which of the following pairs are the two terms equivalent? embryo sac - female gametophyte microspore - pollen grain seed - zygote ovule - egg
embryo sac - female gametophyte
Angiosperms are the most successful terrestrial plants. Which of the following features is unique to them and helps account for their success? fruits enclosing seeds dominant gametophytes wind pollination sperm cells without flagella
fruits enclosing seeds
Regardless of where in the world a vineyard is located, for the winery to produce a Burgundy, it must use varietal grapes that originated in Burgundy, France. The most effective way for a new California grower to plant a vineyard to produce Burgundy is to _____. graft varietal Burgundy grape scions onto native (Californian) root stocks transplant varietal Burgundy plants from France plant seeds obtained from French varietal Burgundy grapes acquire a tissue culture of varietal Burgundy grapes from France
graft varietal Burgundy grape scions onto native (Californian) root stocks
A summer occupation in the Corn Belt states is de-tasseling the corn: removing unwanted male flowers so that female flowers on the same plant are pollinated by the desired pollen for the hybrid corn. What does this tell you about corn? The flowers are _____. imperfect and the plant is dioecious perfect and the plant is dioecious perfect and the plant is monoecious imperfect and the plant is monoecious
imperfect and the plant is monoecious
Which of the following could be considered an evolutionary advantage of asexual reproduction in plants? increased agricultural productivity in a rapidly changing environment. increased ability to adapt to a change in the environment. increased success of progeny in a stable environment. maintenance and expansion of a large genome.
increased success of progeny in a stable environment.
The generative cell of male angiosperm gametophytes is haploid. This cell divides to produce two haploid sperm cells. What type of cell division does the generative cell undergo to produce these sperm cells? meiosis without subsequent cytokinesis mitosis without subsequent cytokinesis mitosis meiosis
mitosis
Plants produce more seeds when they reproduce asexually than sexually. Yet most plants reproduce sexually in nature. What is the probable explanation for the prevalence of sexual reproduction? Sexual reproduction _____.
mixes up alleles contributing to variation in a species
Double fertilization means that _____. every sperm has two nuclei the egg of the embryo sac is diploid flowers must be pollinated twice to yield fruits and seeds one sperm is needed to fertilize the egg, and a second sperm is needed to fertilize the polar nuclei
one sperm is needed to fertilize the egg, and a second sperm is needed to fertilize the polar nuclei
Which of the following flower parts develops into the pulp of a fleshy fruit? ovule style ovary stigma
ovary
Which of the following flower parts develops into a seed? ovary stamen ovule carpel
ovule
Use the following information to answer the question(s) below. 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 tall, 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. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal 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 now enter. The uneaten seeds may subsequently germinate. 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?
pollination failure
The vast number and variety of flower species is probably related to various kinds of _____. seed dispersal agents climatic conditions pollinators herbivores
pollinators
Pollen from a plant with the S1S2 genotype is recognized and allowed to germinate on the stigma of the same plant with the S1S2 genotype. According to the S-system hypothesis, this indicates that the plant is _____. self-incompatible and can self-pollinate. self-incompatible and must cross-pollinate. self-compatible and must cross-pollinate. self-compatible and can self-pollinate.
self-compatible and can self-pollinate.
Which of the following is the correct order of floral organs from the outside to the inside of a complete flower? Which of the following is the correct order of floral organs from the outside to the inside of a complete flower? sepals → petals → stamens → carpels sepals → stamens → petals → carpels spores → gametes → zygote → embryo petals → sepals → stamens → carpels
sepals → petals → stamens → carpels
Before plowing a field, a farmer thought the bare field looked weed-free. Three days after plowing and turning over the soil, he was amazed to see thousands of tiny seedlings. What is the most likely reason for the mass germination of seeds? large seeds that needed soil disturbance to germinate small seeds that need light to germinate large seeds that needed exposure to higher levels of oxygen to germinate small seeds that were scarified by exposure to plow
small seeds that need light to germinate
Use the following information to answer the question(s) below. 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 tall, 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. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal 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 now enter. The uneaten seeds may subsequently germinate. The agouti is most directly involved with the Brazil nut tree's dispersal of _____. female gametophytes sporophyte embryos sporophyte megaspores male gametophytes
sporophyte embryos
hich of the following would be the most problematic for the natural environment in the development of genetically engineered crops? the creation of transgenic crops with apomictic seeds the introduction of male sterility into crops the creation of transgenic crops that hybridize more easily the creation of crops with flowers that develop normally, but fail to open
the creation of transgenic crops that hybridize more easily
Which of these is a major trend in land plant evolution? the trend toward a sporophyte-dominated life cycle the trend toward larger gametophytes the trend toward a gametophyte-dominated life cycle the trend toward smaller size
the trend toward a sporophyte-dominated life cycle
Fruit ripening represents an example of positive feedback. Which one of the following statements accurately justifies why the process of fruit ripening involves positive feedback? Once seeds have reached maturity, chemical signals block enzymatic steps that normally convert sugars into starches and sugars accumulate from photosynthetic activity within the fruit. Once seeds have reached maturity, chemical signals increase enzymatic activity in fruit to convert sugars into starches, thicken pulp, and maintain color in the fruit. Chemical signals shut down enzymatic activity within the fruit, which results in breakdown of starches into sugars, softening of pulp, and color change of fruit. Chemical signals initiate a process that triggers enzymatic activity, which involves converting starches into sugars, softening of pulp, and color change of fruit.
Chemical signals initiate a process that triggers enzymatic activity, which involves converting starches into sugars, softening of pulp, and color change of fruit.
Many flowering plants coevolve with specific pollinators. The Madagascar orchid has a 12-inch floral tube and is a reliable nectar source for the hawkmoth, which has a correspondingly long proboscis (tongue). Which statement most accurately describes how coevolution might have occurred for the hawkmoth and Madagascar orchid shown here? The hawkmoths that expended the most effort to reach the nectar would be the most fit, and pass the longer tongue phenotype to their offspring. It is most likely that mutations that resulted in both the length of the orchid floral tube and the length of the hawkmoth tongue occurred abruptly and simultaneously. Hawkmoths whose tongue was just long enough to obtain nectar, but not able to pick up pollen would become the most fit in the population. Natural selection would favor orchids with nectar tubes just long enough to for an insect with pollen to make contact. Hawkmoths whose tongue could reach the deep tubes would be more fit.
Natural selection would favor orchids with nectar tubes just long enough to for an insect with pollen to make contact. Hawkmoths whose tongue could reach the deep tubes would be more fit.
Which of the following statements regarding flowering plants is correct? The gametophyte is the dominant generation. Female gametophytes develop from megaspores within the anthers. Pollination is the delivery of pollen to the stigma of a carpel. The food-storing endosperm is derived from the cell that contains one polar nucleus and two sperm nuclei.
Pollination is the delivery of pollen to the stigma of a carpel.
The egg of a plant has a haploid chromosome number of 12 (n = 12). What is true about the number of chromosomes in the cells of other tissues of this plant? The endosperm has 36 chromosomes. The leaves and stems have 12 chromosomes. The sperm has 6 chromosomes. The zygote has 12 chromosomes.
The endosperm has 36 chromosomes.
It is estimated that animal-pollinated or insect-pollinated plants produce 1000 pollen grains for each ovule; wind-pollinated plants produce 1,000,000 pollen grains for each ovule. What does that indicate about pollination systems? Wind-pollinated plants rarely produce seeds. Wind pollination is costlier to the plant than animal-assisted pollination. Wind pollination is more efficient than animal-assisted pollination. Wind pollination is less efficient than animal-assisted pollination.
Wind pollination is less efficient than animal-assisted pollination.
Retaining the zygote on the living gametophyte of land plants _____. protects the zygote from herbivores evolved concurrently with pollen allows it to be nourished by the parent plant helps in dispersal of the zygote
allows it to be nourished by the parent plant
Over human history, which process has been most important in improving the features of plants that have long been used by humans as staple foods? pesticide and herbicide application genetic engineering sexual selection artificial selection
artificial selection