Ch. 30-33 Flashcards


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1

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

Orchid bees are to Brazil nut trees as ________ are to pine trees.

A) breezes

B) rain droplets

C) seed-eating birds

D) squirrels

A) breezes

2

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

The large white part of a Brazil nut that people eat serves which of the following functions in nature?

A) It attracts harpy eagles and encourages them to nest in the tree.

B) It provides energy and nutrition to a germinating seedling.

C) It serves as protection for the embryo from agoutis looking for food.

D) It provides a water source for the developing embryo.

B) It provides energy and nutrition to a germinating seedling.

3

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

Predict the most likely outcome to the population of Brazil nut trees if a disease decimated the agouti population.

A) The population of large Brazil nut trees would remain constant for a while, but the population of new seedlings would likely increase in the long run.

B) The population of large Brazil nut trees would decline immediately, and the population of new seedlings would likely decrease in the future.

C) The population of large Brazil nut trees would remain constant for a while, but the population of new seedlings would likely decrease in the long run.

D) Both the population of large Brazil nut trees and new seedlings would increase in the long run.

C) The population of large Brazil nut trees would remain constant for a while, but the population of new seedlings would likely decrease in the long run.

4

Many mammals have skins and mucous membranes that are sensitive to phenolic secretions of plants like poison oak (Rhus). These secondary compounds are primarily adaptations that ________.

A) favor pollination

B) foster seed dispersal

C) decrease competition

D) inhibit herbivory

D) inhibit herbivory

5

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to 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?

A) poor sporophyte viability

B) failure to produce fertile ovules

C) failure to produce pollen

D) pollination failure

D) pollination failure

6

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

The agouti is most directly involved with the Brazil nut tree's dispersal of ________.

A) female gametophytes

B) sporophyte embryos

C) sporophyte megaspores

D) female gametes

B) sporophyte embryos

7

Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to 250 flowers. In certain populations in the Arizona mountains, however, the flowers range from red to pink to white. In early summer, most (but not all) of the flowers were red. Six to eight weeks later, the same individual plants were still present; the flowers ranged from pink to white, and few red flowers were present. The major pollinators early in the season were two species of hummingbirds active during the day; they emigrated to lower elevations, and the major pollinator later in the season was a hawk moth (a type of moth). The hawk moth was most active at sunset and later, and it preferred light pink to white flowers after dark. When hummingbirds were present, more red flowers than white flowers produced fruit. When only hawk moths were present, more white flowers produced fruit. (K. N. Paige and T. G. Whitham. 1985. Individual and population shifts in flower color by scarlet gilia: A mechanism for pollinator tracking. Science 227:315-17).

What is the significance of measuring fruit production?

A) It is a measure of pollination success.

B) It is a measure of seed dispersal success.

C) It is easier than counting flowers.

D) It is an indication of predation on the seeds of the plants.

A) It is a measure of pollination success.

8

Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to 250 flowers. In certain populations in the Arizona mountains, however, the flowers range from red to pink to white. In early summer, most (but not all) of the flowers were red. Six to eight weeks later, the same individual plants were still present; the flowers ranged from pink to white, and few red flowers were present. The major pollinators early in the season were two species of hummingbirds active during the day; they emigrated to lower elevations, and the major pollinator later in the season was a hawk moth (a type of moth). The hawk moth was most active at sunset and later, and it preferred light pink to white flowers after dark. When hummingbirds were present, more red flowers than white flowers produced fruit. When only hawk moths were present, more white flowers produced fruit (K. N. Paige and T. G. Whitham. 1985. Individual and population shifts in flower color by scarlet gilia: A mechanism for pollinator tracking. Science 227:315-17).

Late in the season, when only hawk moths were present, researchers painted the red flowers white. What would you expect?

A) Unpainted red flowers would produce more fruits than white flowers would.

B) Red flowers painted white would produce more fruits than red flowers would.

C) Red and white flowers would produce the same numbers of fruits.

D) Unpainted red flowers would produce the same number of fruits as the white flowers.

B) Red flowers painted white would produce more fruits than red flowers would.

9

Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to 250 flowers. In certain populations in the Arizona mountains, however, the flowers range from red to pink to white. In early summer, most (but not all) of the flowers were red. Six to eight weeks later, the same individual plants were still present; the flowers ranged from pink to white, and few red flowers were present. The major pollinators early in the season were two species of hummingbirds active during the day; they emigrated to lower elevations, and the major pollinator later in the season was a hawk moth (a type of moth). The hawk moth was most active at sunset and later, and it preferred light pink to white flowers after dark. When hummingbirds were present, more red flowers than white flowers produced fruit. When only hawk moths were present, more white flowers produced fruit (K. N. Paige and T. G. Whitham. 1985. Individual and population shifts in flower color by scarlet gilia: A mechanism for pollinator tracking. Science 227:315-17).

Some plants continued to produce only dark (red) flowers whereas others produced lighter colored flowers later in the season. Which plants do you expect produced more fruit over the entire season?

A) those that changed their color to a lighter shade

B) those that stayed dark

C) the same numbers of fruit on both

D) the plants whose flowers were always light colored

A) those that changed their color to a lighter shade

10

Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to 250 flowers. In certain populations in the Arizona mountains, however, the flowers range from red to pink to white. In early summer, most (but not all) of the flowers were red. Six to eight weeks later, the same individual plants were still present; the flowers ranged from pink to white, and few red flowers were present. The major pollinators early in the season were two species of hummingbirds active during the day; they emigrated to lower elevations, and the major pollinator later in the season was a hawk moth (a type of moth). The hawk moth was most active at sunset and later, and it preferred light pink to white flowers after dark. When hummingbirds were present, more red flowers than white flowers produced fruit. When only hawk moths were present, more white flowers produced fruit (K. N. Paige and T. G. Whitham. 1985. Individual and population shifts in flower color by scarlet gilia: A mechanism for pollinator tracking. Science 227:315-17).

Which of the following proposed controls would be most appropriate for the experiment when, late in the season, scientists painted some of the red flowers white?

A) Some red flowers should be painted pink

B) Some red and light colored flowers should be covered to prevent pollinator access.

C) Plants with light and dark colored flowers should be fertilized.

D) A necessary control would be to put red paint on some of the red flowers in order to control for the effects of paint.

D) A necessary control would be to put red paint on some of the red flowers in order to control for the effects of paint.

11

Immature seed cones of conifers are usually green before pollination, and flowers of grasses are inconspicuously colored. What does this indicate about their pollination?

A) They probably self-fertilize and do not need pollen carried from one plant to another.

B) Their pollinating insects are probably color blind.

C) They are probably wind pollinated.

D) They probably attract pollinators using strong fragrances.

C) They are probably wind pollinated.

12

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 a tube cell nucleus?

A) 8

B) 16

C) 24

D) 32

A) 8

13

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 endosperm nucleus?

A) 8

B) 16

C) 24

D) 32

C) 24

14

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 a generative cell nucleus?

A) 8

B) 16

C) 24

D) 32

A) 8

15

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 the nucleus of an egg within the embryo sac prior to fertilization?

A) 8

B) 16

C) 24

D) 32

A) 8

16

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 after fertilization?

A) 8

B) 16

C) 24

D) 32

B) 16

17

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 a megasporangium nucleus?

A) 8

B) 16

C) 24

D) 32

B) 16

18

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

Animals that consume Brazil nuts derive nutrition mostly from tissue whose nuclei have how many chromosomes?

A) 17

B) 34

C) 51

D) 68

C) 51

19

Which of the following sex and generation combinations directly produces the fruit of angiosperms?

A) male gametophyte

B) female gametophyte

C) male sporophyte

D) female sporophyte

D) female sporophyte

20

Which of the following is a characteristic of all angiosperms?

A) double internal fertilization

B) free-living gametophytes

C) carpels that contain microsporangia

D) ovules that are not contained within ovaries

A) double internal fertilization

21

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?

A) The seed coat, upon its complete digestion, should provide vitamins or nutrients to animals.

B) The exterior of the seed coat should have barbs or hooks, and the seed coat should contain secondary compounds that irritate the lining of the animal's mouth.

C) The seed coat should contain secondary compounds that irritate the lining of the animal's mouth, and the seed coat should be able to withstand high acidity.

D) The seed coat should be able to withstand high acidity, and the seed coat should be resistant to the animal's digestive enzymes.

D) The seed coat should be able to withstand high acidity, and the seed coat should be resistant to the animal's digestive enzymes.

22

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?

A) binary fission

B) mitosis

C) meiosis

D) meiosis without subsequent cytokinesis

B) mitosis

23

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 likely accurate?

A) The flowers that gave rise to such pods were not pollinated, and fruit can develop even if all ovules within have not been fertilized.

B) Pollen tubes did not enter all of the ovules in such pods, and the ovules that failed to develop into seeds were derived from sterile floral parts.

C) Pollen tubes did not enter all of the ovules in such pods, and fruit can develop even if all ovules within have not been fertilized.

D) There was apparently not enough endosperm to distribute to all of the ovules in such pods, and fruit can develop even if all ovules within have not been fertilized.

C) Pollen tubes did not enter all of the ovules in such pods, and fruit can develop even if all ovules within have not been fertilized.

24

Arrange the following structures from largest to smallest, assuming that they belong to two generations of the same angiosperm.

A) carpel, embryo sac, ovule, ovary, egg

B) embryo sac, carpel, egg, ovary, ovule

C) embryo sac, ovary, carpel, ovule, egg

D) carpel, ovary, ovule, embryo sac, egg

D) carpel, ovary, ovule, embryo sac, egg

25

Mistletoe is a plant that lives on trees and gains nutrition from them (that is, it is a parasite). The fruit of the mistletoe is a one-seeded berry and is consumed by birds. In members of the genus Viscum, the outside of the seed is viscous (sticky), which permits the seed to adhere to surfaces such as the branches of host plants or the beaks of birds. What should be expected of the fruit if the viscosity of Viscum seeds is primarily an adaptation for dispersal rather than an adaptation for infecting host plant tissues? The fruit ________.

A) is drab in color

B) is colored so as to provide it with camouflage

C) is nutritious to the dispersing organisms

D) secretes enzymes that can digest bark

C) is nutritious to the dispersing organisms

26

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 from the 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?

A) They have exposed ovules.

B) They have flagellated sperm.

C) They are pollinated by animals.

D) They have flagellated sperm, and they are pollinated by animals.

C) They are pollinated by animals.

27

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 from the 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 the ________.

A) extent to which their overall activities affect cycad reproduction

B) extent to which the beetles are affected by the neurotoxins

C) extent to which the beetles damage the cycad flowers

D) distance the beetles must travel between cycad microsporophylls and cycad megasporophylls

A) extent to which their overall activities affect cycad reproduction

28

If one were to propose a new taxon of plants that included all the plants that are pollinated by animals, but excluded all plants that are not pollinated by animals, then this new taxon would be ________.

A) monophyletic

B) paraphyletic

C) polyphyletic

D) identical in composition to the phylum Anthophyta

C) polyphyletic

29

Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female's body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.

The yolk of an animal egg has what type of analog in angiosperms?

A) endosperm

B) carpels

C) fruit

D) seed coat

A) endosperm

30

Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female's body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.

The shell of a fertilized animal egg has what type of analog in angiosperms?

A) endosperm

B) carpels

C) fruit

D) seed coat

D) seed coat

31

Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female's body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.

The internal fertilization that occurs prior to shell deposition has what type of analog in angiosperms?

A) endosperm proliferation

B) growth of pollen tube and delivery of sperm nuclei

C) fusion of carpels into a fruit

D) seed coat hardening

B) growth of pollen tube and delivery of sperm nuclei

32

Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female's body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.

The laying of eggs has what type of analog in angiosperms?

A) endosperm breakdown

B) fusion of carpels into a fruit

C) fruit dispersal

D) seed coat hardening

C) fruit dispersal

33

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to 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?

A) pollination, pollen tube emerges from pollen grain, pollen tube enters micropyle, double fertilization

B) pollination, pollen tube enters micropyle, pollen tube emerges from pollen grain, double fertilization

C) pollen tube emerges from pollen grain, pollination, pollen tube enters micropyle, double fertilization

D) pollen tube enters micropyle, pollen tube emerges from pollen grain, pollination, double fertilization

A) pollination, pollen tube emerges from pollen grain, pollen tube enters micropyle, double fertilization

34

Stamens, sepals, petals, carpels, and pinecone scales are all ________.

A) female reproductive parts

B) capable of photosynthesis

C) modified leaves

D) found on flowers

C) modified leaves

35

Compared to animal-pollinated plants, wind-pollinated angiosperms ________.

A) produce fewer seeds because winds disperse seeds in a targeted manner

B) produce more seeds because winds disperse seeds greater distances

C) produce much less pollen because winds disperse pollen in a highly targeted manner

D) produce much more pollen because winds disperse pollen randomly

D) produce much more pollen because winds disperse pollen randomly

36

Archaefructus, an early fossil angiosperm, was herbaceous and probably aquatic. Other seed plant fossils were woody and terrestrial. What should scientists conclude?

A) The earliest angiosperms were herbaceous and aquatic.

B) The earliest angiosperms were woody and terrestrial.

C) Other data must be considered in order to make a valid conclusion.

D) We cannot know the real history of angiosperms.

C) Other data must be considered in order to make a valid conclusion.

37

Imagine that you wanted to know if speciation is more rapid in plant groups pollinated by bees or hummingbirds. To do this, you identified 20 genera of angiosperms that contained species pollinated by both types of animals. There were substantially more species in the groups that were pollinated by bees. What conclusions can you draw from your data?

A) Hummingbirds promoted speciation more than did bees.

B) Hummingbirds promoted speciation less than did bees.

C) Each genus should be split into two new genera.

D) The rates of speciation were similar in groups pollinated by hummingbirds and bees.

B) Hummingbirds promoted speciation less than did bees.

38
card image

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

Ecologists often build models to depict the relationships between organisms. In such models, an arrow is used to link two organisms in a relationship. The arrowhead is next to the organism that is affected. If the effect is positive, the arrow is labeled with (+), and if negative, then the label is (-). Which of the following models best illustrates the direct relationships of the Brazil nut tree and the other organisms associated with it?

card image
39
card image

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, a source of high-quality lumber, and 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 then enter and allow the remaining seeds to germinate.

Ecologists often build models to depict the relationships between organisms. In such models, an arrow is used to link two organisms in a relationship. The arrowhead is next to the organism that is affected. If the effect is positive, the arrow is labeled with (+), and if negative, then the label is (-). Capuchin monkeys have been known to use rocks to smash open the fruits of Brazil nut trees. On the rare occasions when this has been observed, the monkeys consume all of the Brazil nuts. Thus, which of the following correctly depicts the direct relationship between capuchin monkeys and Brazil nut trees?

card image
40

In the United States and Canada, bats use one of two strategies to survive winter. They either migrate south, or they hibernate. Recently, those that hibernate seem to have come under attack by a fungus, Geomyces destructans (Gd), an attack that is occurring from Missouri to New England, Canada, and even the state of Washington. Many infected bats have a delicate, white filamentous mat on their muzzles, which is referred to as white-nose syndrome (WNS). The fungus invades the bat tissues, causes discomfort, and awakens the bat from its hibernation. The bat fidgets and wastes calories, using up its stored fat. The bat then behaves abnormally, leaving its cave during daytime in winter to search for food. Their food, primarily insects, is scarce during the winter, and the bats ultimately starve to death. Since 2006, it is estimated that over six million bats have perished from WNS.

The Gd mat on the fur of the bats should be expected to consist of ________.

A) hyphae

B) haustoria

C) yeasts

D) basidia

A) hyphae

41

What do fungi and arthropods have in common?

A) The haploid state is dominant in both groups.

B) Both groups are predominantly autotrophs that produce their own food.

C) Both groups use chitin for support.

D) Both groups have cell walls.

C) Both groups use chitin for support.

42

Fungi have an extremely high surface-to-volume ratio. What is the advantage of this characteristic to an organism that gets most of its nutrition through absorption?

A) The high ratio allows for more material to be acquired from the surroundings and transported through the cell membrane.

B) The lower volume prevents the cells from drying out too quickly, which can interfere with absorption.

C) This high ratio creates more room inside the cells for additional organelles involved in absorption.

D) This high ratio means that fungi have a thick, fleshy structure that allows the fungi to store more of the food it absorbs.

A) The high ratio allows for more material to be acquired from the surroundings and transported through the cell membrane.

43

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).

Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A

Which of the following results would support Simard et al.'s (1997) hypothesis that fungi can move carbon from one plant to another? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.]

A) Carbon-14 is found in the birch seedling's tissues and carbon-13 in the Douglas fir.

B) Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.

C) Either carbon-13 or carbon-14 is found in the fungal tissues.

D) Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

B) Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.

44

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).

Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A

Based on the idea that fungi have pores between their cell walls that 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.

A) If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon could travel from one plant to another.

45

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Based on the graphs in the figure, which of the following plant species is most likely not to form mycorrhizal associations?

A) Carex flacca (graph a)

B) Lotus corniculatus (graph b)

C) Sanguisorba officinalis (graph c)

D) Centaurium erythrea (graph d)

A) Carex flacca (graph a)

46

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Examine the effect of AMF species on Sanguisorba officinalis. Which of the following conclusions can be correctly drawn from the data?

A) Growth is best with AMF species D.

B) Growth is best with AMF species A.

C) Growth is best with a mixture of AMF species.

D) AMF presence had no effect on officinalis growth.

B) Growth is best with AMF species A.

47

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Examine all four graphs and choose the plant species that grows best with a combination of AMF species.

A) Carex flacca (graph a)

B) Lotus corniculatus (graph b)

C) Sanguisorba officinalis (graph c)

D) Centaurium erythrea (graph d)

B) Lotus corniculatus (graph b)

48

If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed?

A) flowering plants

B) protists

C) prokaryotes

D) grasses

C) prokaryotes

49

When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?

A) fungal haustoria

B) fungal enzymes

C) increased oxygen levels

D) larger bacterial populations

B) fungal enzymes

50

A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the fungal movement, as described here?

A) karyogamy

B) mycelial flagella

C) breezes distributing spores

D) cytoplasmic streaming in hyphae

D) cytoplasmic streaming in hyphae

51

When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the ________.

A) fungicide might also kill the native yeasts residing on the surfaces of the grapes

B) lichens growing on the vines' branches are not harmed

C) fungicide might also kill mycorrhizae

D) sheeting is transparent so that photosynthesis can continue

C) fungicide might also kill mycorrhizae

52

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to ________.

A) the ability to form haustoria and parasitize other organisms

B) the potential to inhabit almost all terrestrial habitats

C) the increased probability of contact between different mating types

D) an extensive surface area well suited for invasive growth and absorptive nutrition

D) an extensive surface area well suited for invasive growth and absorptive nutrition

53

Some fungal species live in plants and can kill herbivores that feed on the plant. What type of relationship does this fungus have with its host?

A) parasitic

B) mutualistic

C) commensal

D) predatory

B) mutualistic

54

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).

Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A

Referring to Simard et al. (1997), what is the result that would most strongly refute their hypothesis? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.]

A) No movement: Carbon-14 is found in the birch seedling's tissues and carbon-13 in the Douglas fir.

B) Reciprocal exchange: Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.

C) Either carbon-13 or carbon-14 is found in the fungal tissues.

D) Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

D) Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

55

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).

Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A

Referring to Simard et al. (1997), which design element is the control in this experiment and why?

A) the bags over the seedlings to contain the different types of carbon dioxide

B) the fact that all the seedlings are different species

C) the cedar seedling, because it is not bagged

D) the cedar seedling, because it does not form ectomycorrhizal connections with the tested fungus

D) the cedar seedling, because it does not form ectomycorrhizal connections with the tested fungus

56

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).

Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Simard et al. (1997) further hypothesized that if reciprocal transfer did occur, it would be a source-sink relationship driven by photosynthetic rates. That is, if one seedling is in full sun and the other in deep shade, there will be a net movement of carbon from the seedling in full sun to the one in deep shade. If a shade were placed over the birch seedlings and the cedar, and the Douglas fir was left in full sun, what result could Simard and colleagues expect?

A) More 13C would be found in the birch than 14C in the Douglas fir.

B) The amounts of 13C and 14C would be equal in the Douglas fir and in the birch.

C) The most 13C would be found in the cedar.

D) The most 14C would be found in the cedar.

A) More 13C would be found in the birch than 14C in the Douglas fir.

57

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Based on the van der Heijden et al. (1998) graphs in the figure, which of the following is the best description of the data supporting the idea that a plant species did not form mycorrhizae with a fungus? Its biomass is greatest when ________.

A) no AMF are present

B) AMF species A is present

C) AMF species B is present

D) AMF species C is present

A) no AMF are present

58

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

In graph b in the figure, which of the following best explains the data given about Lotus corniculatus?

A) This plant grows best when AMF taxa A or C is present.

B) Lotus corniculatus does not form mycorrhizal associations.

C) Mycorrhizal fungi parasitize the plant's roots when they are present, reducing its growth.

D) This plant forms multiple AMF associations, growing best with increased fungal diversity.

D) This plant forms multiple AMF associations, growing best with increased fungal diversity.

59

Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

What is the major difference between Bromus erectus (graph f) and the other plant species (graphs a-d) included in the study?

A) Bromus erectus grows best with a diversity of fungal partners.

B) Bromus erectus is unaffected by AMF diversity.

C) Bromus erectus does not form mycorrhizal associations.

D) Bromus erectus produces very little biomass regardless of AMF.

B) Bromus erectus is unaffected by AMF diversity.

60

Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

What is the most likely explanation for the observation that total biomass (graph e) does not vary with AMF diversity?

A) Plant growth is unaffected by fungal diversity.

B) Most of the plants in this system do not form mycorrhizal associations.

C) Bromus erectus is the dominant plant species.

D) Lotus corniculatus is a rare species.

C) Bromus erectus is the dominant plant species.

61

Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.

On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

Based on graphs e and f, which is the most well-supported prediction for the effect on total plant biomass if AMF diversity were increased to eight species?

A) No effect is predicted, because the dominant species is unaffected by AMF diversity.

B) Total biomass for eight species would double in comparison to that for four species.

C) Rare species would produce more biomass compared to the case when fewer AMF are present.

D) No effect is predicted, because the dominant species is non-mycorrhizal.

A) No effect is predicted, because the dominant species is unaffected by AMF diversity.

62

Some companies advertise and sell mycorrhizae to home gardeners and commercial farms, claiming that the presence of mycorrhizae improves plant growth and survival. If the company conducted experiments on plants with and without mycorrhizae, which of the following measurements would support their claim?

A) smaller apple size in plants with mycorrhizae than in plants without mycorrhizae

B) increased production of corn ears in plants with mycorrhizae than in plants without mycorrhizae

C) increased need for fertilizer in plants with mycorrhizae than in plants without mycorrhizae

D) increased mortality in plants with mycorrhizae than in plants without mycorrhizae

B) increased production of corn ears in plants with mycorrhizae than in plants without mycorrhizae

63

Some nematode worms suck plant juices from the roots of plants and are economically important agricultural pests. Some fungi are usually decomposers of plant material, but some trap and kill nematodes at times. Arthrobotrys traps and kills nematodes, especially when they lack nitrogen sources. These two facts suggest that farmers could find Arthrobotrys an important tool in combating nematode infestations. Which of the following research questions would make a good starting point for developing such a defense against plant-sucking nematodes?

A) Does nitrogen fertilization of crops affect the likelihood that Arthrobotrys will trap and kill nematodes?

B) Do nitrogen-fixing bacteria provide nitrogen to the fungi?

C) What is the evolutionarily oldest method of trapping nematodes?

D) What mechanisms do nematodes have that could allow them to escape from Arthrobotrys?

A) Does nitrogen fertilization of crops affect the likelihood that Arthrobotrys will trap and kill nematodes?

64

Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

A) Hyphae are 100 to 1,000 times larger than plant roots.

B) Hyphae have a smaller surface area-to-volume ratio than do the hairs on a plant root.

C) Mycelia are able to grow in the direction of food.

D) Fungi secrete extracellular enzymes that can break down large molecules.

D) Fungi secrete extracellular enzymes that can break down large molecules.

65

Fossil fungi date back to the origin and early evolution of plants. What combination of environmental and morphological change is similar in the evolution of both fungi and plants?

A) presence of "coal forests" and change in mode of nutrition

B) periods of drought and presence of filamentous body shape

C) predominance in swamps and presence of cellulose in cell walls

D) colonization of land and loss of flagellated cells

D) colonization of land and loss of flagellated cells

66

The multicellular condition of animals and fungi seems to have arisen ________.

A) due to common ancestry

B) by convergent evolution

C) by inheritance of acquired traits

D) by serial endosymbioses

B) by convergent evolution

67

Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?

A) the absence of chitin within the cell wall

B) coenocytic hyphae

C) flagellated spores

D) parasitic lifestyle

C) flagellated spores

68

Chitin is a long-chain polymer derived from glucose. It strengthens cell walls of fungi and the outer covering (exoskeleton) of arthropods (including crabs, shrimps, and insects). The presence of chitin in these groups is likely due to ________.

A) secondary endoparasitism

B) horizontal gene transfer

C) paraphyletic evolution

D) convergent evolution

D) convergent evolution

69

Early fungi probably formed mutualistic associations with early plants, providing nutrients to the plant and receiving energy-containing compounds. Evidence that plants' ability to form a mutualistic association with fungi is due to ancient genes includes which of the following occurrences?

A) presence of genes in the earliest fungi that showed an ability to digest cellulose and lignin

B) presence of genes for chitin in the oldest flowering plants and oldest fungi

C) fossils that show hyphae wrapped around seeds

D) restoration of the ability to form mycorrhizae with fungi by a flowering plant after biologists transferred a gene from a liverwort to the flowering plant

D) restoration of the ability to form mycorrhizae with fungi by a flowering plant after biologists transferred a gene from a liverwort to the flowering plant

70

A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes are absolutely conserved, which of the following would be the best choice on which to base the phylogeny?

A) genes involved in chitin synthesis

B) collagen genes

C) genes involved in directing segmentation development

D) genes involved in eye-lens synthesis

B) collagen genes

71

Which of the following is (are) unique to animals?

A) the structural carbohydrate, chitin

B) nervous system signal conduction and muscular movement

C) heterotrophy

D) flagellated gametes

B) nervous system signal conduction and muscular movement

72

The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following is most directly involved in the evolution of these variations in metamorphosis?

A) artificial selection of sexually immature forms of insects

B) changes in the homeobox genes controlling early development

C) the evolution of meiosis

D) the origin of a brain

B) changes in the homeobox genes controlling early development

73

As you are on the way to Tahiti for a vacation, your plane crash lands on a previously undiscovered island. You soon find that the island is teeming with unfamiliar organisms, and you, as a student of biology, decide to survey them (with the aid of the Insta-Lab Portable Laboratory you brought along in your suitcase). You select four organisms and observe them in detail, making the notations found in the figure.

Which organism would you classify as an animal?

A) organism A

B) organism B

C) organism C

D) organism D

C) organism C

74

As you are on the way to Tahiti for a vacation, your plane crash lands on a previously undiscovered island. You soon find that the island is teeming with unfamiliar organisms, and you, as a student of biology, decide to survey them (with the aid of the Insta-Lab Portable Laboratory you brought along in your suitcase). You select four organisms and observe them in detail, making the notations found in the figure.

In which of the organisms listed would you search for photosynthetic genes?

A) organism A

B) organism B

C) organism C

D) organism D

B) organism B

75

As you are on the way to Tahiti for a vacation, your plane crash lands on a previously undiscovered island. You soon find that the island is teeming with unfamiliar organisms, and you, as a student of biology, decide to survey them (with the aid of the Insta-Lab Portable Laboratory you brought along in your suitcase). You select four organisms and observe them in detail, making the notations found in the figure.

In which of the organisms listed would you search for collagen?

A) organism A

B) organism B

C) organism C

D) organism D

C) organism C

76

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by ________.

A) preying on animals

B) ingesting materials

C) consuming living, rather than dead, prey

D) using enzymes to digest their food

B) ingesting materials

77

Trichoplax adhaerens is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 µm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage.

Which of the following T. adhaerens traits is different from all other known animals?

A) adhaerens is multicellular.

B) adhaerens lacks muscle and nerve cells.

C) adhaerens has cilia.

D) adhaerens lacks cell walls.

B) adhaerens lacks muscle and nerve cells.

78

What do animals ranging from corals to monkeys have in common?

A) a mouth and an anus

B) number of embryonic tissue layers

C) some type of body symmetry

D) presence of Hox genes

D) presence of Hox genes

79

In individual insects of some species, whole chromosomes that carry larval genes are eliminated from the genomes of somatic cells at the time of metamorphosis. A consequence of this occurrence is that ________.

A) we could not clone a larva from the somatic cells of such an adult insect

B) such species must reproduce only asexually

C) the descendants of these adults do not include a larval stage

D) metamorphosis can no longer occur among the descendants of such adults

A) we could not clone a larva from the somatic cells of such an adult insect

80

Which tissue type or organ is not correctly matched with its germ layer tissue?

A) nervous—mesoderm

B) muscular—mesoderm

C) stomach—endoderm

D) skin—ectoderm

A) nervous—mesoderm

81

While looking at some seawater through your microscope, you spot the egg of an unknown animal. Which of the following tests could you use to determine whether the developing organism is a protostome or a deuterostome? See whether the embryo ________.

A) develops germ layers

B) exhibits spiral cleavage or radial cleavage

C) develops a blastopore

D) develops an archenteron

B) exhibits spiral cleavage or radial cleavage

82

In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome?

A) There is evidence of cephalization.

B) The animal is triploblastic.

C) The animal is clearly bilaterally symmetrical.

D) You see a mouth, but not an anus.

D) You see a mouth, but not an anus.

83

Which of the following is a feature of the "tube-within-a-tube" body plan in most animal phyla?

A) The outer tube consists of a hard exoskeleton.

B) The outer tube consists of digestive organs.

C) The mouth and anus form the ends of the inner tube.

D) The two "tubes" are separated by tissue that comes from embryonic endoderm.

C) The mouth and anus form the ends of the inner tube.

84

If you think of the earthworm body plan as a drinking straw within a pipe, where would you expect to find most of the tissues that developed from endoderm?

A) lining the straw

B) lining the space between the pipe and the straw

C) forming the outside of the pipe

D) forming the outside of the straw

A) lining the straw

85

Among protostomes, which morphological trait has shown the most variation?

A) type of symmetry (bilateral versus radial versus none)

B) type of body cavity (coelom versus pseudocoelom versus no coelom)

C) number of embryonic tissue types (diploblasty versus triploblasty)

D) type of development (protostome versus deuterostome)

B) type of body cavity (coelom versus pseudocoelom versus no coelom)

86

What do all deuterostomes have in common?

A) Adults are bilaterally symmetrical.

B) Embryos have pharyngeal pouches that may or may not form gill slits.

C) All have a spinal column.

D) The pore (blastopore) formed during gastrulation becomes the anus.

D) The pore (blastopore) formed during gastrulation becomes the anus.

87

Soon after the coelom begins to form, a researcher injects a dye into the coelom of a deuterostome embryo. Initially, the dye should be able to flow directly into the ________.

A) blastopore

B) blastocoel

C) archenteron

D) pseudocoelom

C) archenteron

88

You have before you a living organism, which you examine carefully. Which of the following should convince you that the organism is acoelomate?

A) It is triploblastic.

B) It has bilateral symmetry.

C) It possesses sensory structures at its anterior end.

D) Muscular activity of its digestive system distorts the body wall.

D) Muscular activity of its digestive system distorts the body wall.

89

One small animal phylum (Placozoa) contains only two species, Trichoplax adhaerens (T. adhaerens) and T. reptans. T. adhaerens is the only species seen in over a century. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed. Embryos up to, but not past, the 64-cell (blastula) stage have been observed.

On the basis of information in the paragraph, which of these should be able to be observed in T. adhaerens?

A) a coelom

B) the process of gastrulation

C) eggs

D) a radially symmetric larval form

C) eggs

90

What was an early selective advantage of a coelom in animals? A coelom ________.

A) contributed to a hydrostatic skeleton, allowing greater range of motion

B) was a more efficient digestive system

C) allowed cephalization and the formation of a cerebral ganglion

D) allowed asexual and sexual reproduction

A) contributed to a hydrostatic skeleton, allowing greater range of motion

91

The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups—Lophotrochozoa and Ecdysozoa. What does this finding suggest?

A) These two subgroups have a common ancestor that was a deuterostome.

B) The protostomes are a polyphyletic group.

C) Division of these two groups occurred after the protostome developmental sequence appeared.

D) The lophotrochozoans are monophyletic.

C) Division of these two groups occurred after the protostome developmental sequence appeared.

92

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise 1 hemisphere of the embryo seem to be rotated 45° and to lie in the grooves between larger, underlying cells. This embryo may potentially develop into a(n) ________.

A) turtle

B) earthworm

C) sea star

D) sea urchin

B) earthworm

93

Which of these statements, if accurate, would support the claim that the ancestral cnidarians had bilateral symmetry?

A) Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects.

B) Cnidarians have fewer Hox genes than bilaterians.

C) All cnidarians are acoelomate.

D) The presence of collar cells.

A) Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects.

94

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise 1 hemisphere of the embryo seem to be rotated 45° and to lie in the grooves between larger, underlying cells. If we were to separate these eight cells and attempt to culture them individually, then what is most likely to happen?

A) All eight cells will die immediately.

B) Each cell may continue development, but only into a nonviable embryo that lacks many parts.

C) Each cell may develop into a full-sized, normal embryo.

D) Each cell may develop into a smaller-than-average, but otherwise normal, embryo.

B) Each cell may continue development, but only into a nonviable embryo that lacks many parts.

95

An organism that exhibits a head with sensory equipment and a brain probably also ________.

A) is bilaterally symmetrical

B) has a coelom

C) is segmented

D) is diploblastic

A) is bilaterally symmetrical

96

Suppose a researcher for a pest-control company developed a chemical that inhibited the development of an embryonic mosquito's endodermal cells. Which of the following would be a likely mechanism by which this pesticide works?

A) The mosquito would develop a weakened exoskeleton that would make it vulnerable to trauma.

B) The mosquito would have trouble digesting food, due to impaired gut function.

C) The mosquito would have trouble with respiration and circulation, due to impaired muscle function.

D) The mosquito wouldn't be affected at all.

B) The mosquito would have trouble digesting food, due to impaired gut function.

97

Nudibranchs, a type of predatory sea slug, can have various protuberances (that is, extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plumules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips.

If nudibranch rhinophores are located at the anterior ends of these sea slugs, then they contribute to the sea slugs' ________.

A) segmentation

B) lack of torsion

C) development of a head

D) identity as lophotrochozoans

C) development of a head

98

Trichoplax adhaerens is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage.

adhaerens' body symmetry seems to be most like that of ________.

A) most sponges

B) cnidarians

C) worms

D) tetrapods

A) most sponges

99

The most ancient branch point in animal phylogeny is the characteristic of having ________.

A) radial or bilateral symmetry

B) diploblastic or triploblastic embryos

C) true tissues or no tissues

D) a body cavity or no body cavity

C) true tissues or no tissues

100

When a scientist describes the "body plan" of a phylum, he or she is implying that ________.

A) organisms direct their own evolution in order to maximize their success

B) animals evolve according to a pre-ordained plan

C) the body shapes we see now have been more successful than others in the past

D) mutations have arisen that allow only some shapes to be produced

C) the body shapes we see now have been more successful than others in the past

101

Which of the following statements comparing symmetry in sessile and swimming animals is most probable?

A) Radial symmetry is more advantageous for active swimming than is bilateral symmetry.

B) Radial symmetry occurs most frequently in animals that catch their prey by rapid swimming.

C) Bilateral symmetry allowed animals to evolve nerves.

D) Bilaterally symmetric animals can be streamlined for swimming, but radially symmetric animals cannot.

D) Bilaterally symmetric animals can be streamlined for swimming, but radially symmetric animals cannot.

102

The primary difference between a coelom and a pseudocoelom is ________.

A) their developmental origin

B) the manner in which they cushion the internal organs

C) a coelom arises in the ectoderm, and a pseudocoelom arises in the endoderm

D) a coelom occurs in triploblastic animals, and a pseudocoelom occurs in diploblastic animals

A) their developmental origin

103

Nine-banded armadillos give birth to four offspring at a time. An amazing fact about these offspring is that they are genetically identical to each other. This fact suggests ________.

A) the young undergo metamorphosis

B) the embryo undergoes radial and indeterminate cleavage

C) the first cell division of the fertilized egg is perpendicular to the vertical axis of the egg

D) the species is pseudocoelomate

B) the embryo undergoes radial and indeterminate cleavage

104

One should expect to find cilia associated with the feeding apparatus of ________.

A) annelids

B) coral animals

C) tapeworms

D) sponges

D) sponges

105

Sponges ________.

A) have larvae that are motile and move via the motion of cilia

B) are the simplest diploblastic animals

C) have a nerve net but not a central nervous system

D) have feeding cells called dinoflagellates

A) have larvae that are motile and move via the motion of cilia

106

Which of the following is most likely to be aquatic?

A) filter feeder

B) mass feeder

C) deposit feeder

D) fluid feeder

A) filter feeder

107

Which of the following can be found in the mesohyl of a sponge?

A) amoebocytes and choanocytes

B) spicules and choanocytes

C) amoebocytes and spicules

D) amoebocytes and polyps

C) amoebocytes and spicules

108
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Which of the following factors, when used to label the horizontal axis of the graph, would account most directly for the shape of the plot?

A) rate of cribrostatin synthesis (molecules/unit time)

B) number of pores per sponge

C) number of spicules per sponge

D) number of choanocytes per sponge

D) number of choanocytes per sponge

109

Healthy corals are brightly colored because they ________.

A) secrete colorful pigments to attract mates

B) host symbionts with colorful photosynthetic pigments

C) build their skeletons from colorful minerals

D) secrete colorful pigments to protect themselves from ultraviolet light

B) host symbionts with colorful photosynthetic pigments

110

In terms of food capture, which sponge cell is most similar to the cnidocyte of a cnidarian?

A) amoebocyte

B) choanocyte

C) epidermal cell

D) pore cell

B) choanocyte

111

The crown-of-thorns sea star, Acanthaster planci, preys on the flesh of live coral. If coral animals are attacked by these sea stars, then what actually provides nutrition to the sea star, and which chemical (besides the toxin within their nematocysts) do the corals rely on for protection?

A) medusae; silica

B) exoskeleton; calcium carbonate

C) polyps; calcium carbonate

D) polyps; silica

C) polyps; calcium carbonate

112

An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates—a parrot fish and a clown fish. She arranged for daily feedings of copepods and feeder fish.

One day, Tommy, a student in an undersupervised class of 40 fifth graders, got the urge to pet Nemo (the clown fish), who was swimming among the waving petals of a pretty underwater "flower" that had a big hole in the midst of the petals. Tommy giggled upon finding that these petals felt sticky. A few hours later, Tommy was in the nurse's office with nausea and cramps. Microscopic examination of his fingers would probably have revealed the presence of ________.

A) teeth marks

B) spines

C) spicules

D) nematocysts

D) nematocysts

113

An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates—a parrot fish and a clown fish. She arranged for daily feedings of copepods and feeder fish.

The teacher and class were especially saddened when the colonial hydrozoan died. They had watched it carefully, and the unfortunate creature never even got to produce offspring by budding. Yet, everyone was elated when one of the students noticed a small colonial hydrozoan growing in a part of the tank far from the location of the original colony. The teacher was apparently unaware that these hydrozoans exhibit ________.

A) spontaneous generation

B) abiogenesis

C) alternation of generations

D) a medusa stage

D) a medusa stage

114

The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines, unlike those of most other sea stars, contain a potent toxin. If it were discovered that crown-of-thorns sea stars do not make this toxin themselves, then the most likely alternative would be that this toxin is ________.

A) derived from the nematocysts of its prey

B) absorbed from the surrounding seawater

C) an endotoxin of cellulose-digesting bacteria that inhabit the sea star's digestive glands

D) injected into individual thorns by mutualistic corals which live on the aboral surfaces of these sea stars

A) derived from the nematocysts of its prey

115
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An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates—a parrot fish and a clown fish. She arranged for daily feedings of copepods and feeder fish.

Normally, the clown fish readily swims among the tentacles of the sea anemones; the parrot fish avoids them. One hypothesis for the clown fish's apparent immunity is that they slowly build a tolerance to the sea anemone's toxin. A second hypothesis is that a chemical in the mucus that coats the clown fish prevents the nematocysts from being triggered. Which of the following graphs supports the second, but not the first, of these hypotheses?

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116
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An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates—a parrot fish and a clown fish. She arranged for daily feedings of copepods and feeder fish.

Normally, the clown fish readily swims among the tentacles of the sea anemones; the parrot fish avoids them. One hypothesis for the clown fish's apparent immunity is that they slowly build a tolerance to the sea anemone's toxin. A second hypothesis is that a chemical in the mucus that coats the clown fish prevents the nematocysts from being triggered. Which of the following graphs supports the first, but not the second, of these hypotheses?

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