Land Plants

The development of the __________ prevents plants from drying out and protects them from microbes.

Which of the following statements about algae and plants is true?

Which of the following homologies is/are shared by land plants and their closest living algal relatives?

In moving to land, which of the following challenges did plants have to overcome?

Plants undergo alternation of generations in which __________.

Gametangia are __________.

In charophytes, __________ protect(s) zygotes from desiccation.

Which is a key difference between alternation of generations in plants and sexual reproduction in nonplant organisms?

Which term is most nearly synonymous with land plants?

A major division in plant systematics is based on whether a particular species has __________.

What structures allow plants to readily take up carbon dioxide from the atmosphere?

Heterosporous plants produce __________.

Ferns and mosses are limited mostly to moist environments because __________.

Three of the following are evidence that charophytes are the closest algal relatives of plants. Select the exception. a. similar sperm structure b. the presence of chloroplasts c. similarities in cell wall formation during cell division d. genetic similarities in chloroplasts

What important role does lignin play in vascular plants? a. It is the major component of the cuticle, which prevents plants from drying out. b. It forms the outer layer of pollen grains. c. It forms the tough, rigid cell walls of water-conducting cells. d. It nourishes the embryo in seed plants.

In this abbreviated diagram, identify the four major plant groups and the key terrestrial adaptation associated with each of the three major branch points.

What important role does lignin play in vascular plants? a. It is the major component of the cuticle, which prevents plants from drying out. b. It forms the outer layer of pollen grains. c. It forms the tough, rigid cell walls of water-conducting cells. d. It nourishes the embryo in seed plants.

Which of the following characteristics of plants is absent in their closest relatives, the charophyte algae? a. chlorophyll b b. cellulose in cell walls c. sexual reproduction d. alternation of multicellular generations

The appearance of cuticle and stomata correlated with what event in the evolution of green plants? a. the first upright growth forms b. the first woody tissues c. growth on land d. the evolution of the first water-conducting tissues

Identify the cloud seen in each photograph. Describe the life cycle events associated with each cloud.

The appearance of cuticle and stomata correlated with what event in the evolution of green plants? a. the first upright growth forms b. the first woody tissues c. growth on land d. the evolution of the first water-conducting tissues

In angiosperms, which of the following is correctly paired with its chromosome count? (A)microspore—n (B)zygote—n (C)egg—2n (D)megaspore—2n

In plants, which of the following are produced by meiosis? a. haploid gametes b. diploid gametes c. haploid spores d. diploid spores

What is a pollen grain? a. male gametophyte b. female gametophyte c. male sporophyte d. sperm

What is a pollen grain? a. male gametophyte b. female gametophyte c. male sporophyte d. sperm

Evaluate the following statements regarding seeds. Select True or False for each statement. T/F They contain an embryo. T/F They contain nutritive tissue for the embryo. T/F They consist entirely of diploid cells. T/F They are also referred to as spores.

Evaluate the following statements regarding seeds. Select True or False for each statement. T/F They contain an embryo. T/F They contain nutritive tissue for the embryo. T/F They consist entirely of diploid cells. T/F They are also referred to as spores.

What does it mean to say that a life cycle is gametophyte dominant versus sporophyte dominant?

What does it mean to say that a life cycle is gametophyte dominant versus sporophyte dominant?

Identify each of the following structures as haploid or diploid. a. sporophyte b. spore c. gametophyte d. zygote

EVOLUTION CONNECTION The history of life has been punctuated by several mass extinctions. For example, the impact of a meteorite may have wiped out most of the dinosaurs and many forms of marine life at the end of the Cretaceous period (see Concept 25.4). Fossils indicate that plants were less severely affected by this mass extinction. What adaptations may have enabled plants to withstand this disaster better than animals?

EVOLUTION CONNECTION DRAW IT Draw a phylogenetic tree that represents our current understanding of evolutionary relationships between a moss, a gymnosperm, a lycophyte, and a fern. Use a charophyte alga as the outgroup. (See Figure 26.5 to review phylogenetic trees.) Label each branch point of the phylogeny with at least one derived character unique to the clade descended from the common ancestor represented by the branch point.

The evolution of cuticle presented plants with a challenge that threatened their ability to live on land. Describe this challenge, and explain why stomata represent a solution. Compare and contrast stomata with the pores found in liverworts.

The evolution of cuticle presented plants with a challenge that threatened their ability to live on land. Describe this challenge, and explain why stomata represent a solution. Compare and contrast stomata with the pores found in liverworts.

Which example below is a clade of nonvascular plants?

When you see a green, "leafy" moss, you are looking at the __________.

Rhizoids __________.

Which of the following produces eggs and sperm?

The gametophyte generation of a moss __________.

Fertilization in moss occurs when sperm swim from a(n) __________ and down the neck of a(n) __________.

How are gametes produced by bryophytes?

In mosses, haploid __________ directly produce buds that grow into gametophores.

Which structure of a bryophyte sporophyte is specialized for gradual spore discharge?

In which bryophyte structure specifically does a zygote develop into an embryo?

Sphagnum is a __________ that forms extensive deposits of partially decayed organic material.

The gametophyte stage of the plant life cycle is most conspicuous in __________.

Suppose an efficient conducting system evolved in a moss that could transport water and other materials as high as a tall tree. Which of the following statements about “trees” of such a species would not be true? a. Spore dispersal distances would probably increase. b. Females could produce only one archegonium. c. Unless its body parts were strengthened, such a “tree” would probably flop over. d. Individuals would probably compete more effectively for access to light.

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Researchers hypothesized that small animals called springtails (a type of arthropod) facilitate sperm transfer in mosses. To test this hypothesis, the researchers grew patches of male and female mosses at varying distances from each other and in the presence or absence of springtails. They later checked to see how many sporophytes were found in each female patch (as an indicator that fertilization had occurred). Their results are shown in the graph here (** means P<0.01, * means P>0.05. What conclusions can be drawn about the role of the springtails during the reproductive cycle of the mosses?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Researchers hypothesized that small animals called springtails (a type of arthropod) facilitate sperm transfer in mosses. To test this hypothesis, the researchers grew patches of male and female mosses at varying distances from each other and in the presence or absence of springtails. They later checked to see how many sporophytes were found in each female patch (as an indicator that fertilization had occurred). Their results are shown in the graph here (** means P<0.01, * means P>0.05. What conclusions can be drawn about the role of the springtails during the reproductive cycle of the mosses?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. What structure do moss sperm use for motility, and how does that reflect the evolution of land plants from green algae?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. What structure do moss sperm use for motility, and how does that reflect the evolution of land plants from green algae?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Beyond the results presented here, what other evidence would be useful when drawing conclusions about the role of springtails in moss reproduction?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Beyond the results presented here, what other evidence would be useful when drawing conclusions about the role of springtails in moss reproduction?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. A friend in your biology study group claims that eggs in mosses are fertilized by spores. What is wrong with that statement?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. A friend in your biology study group claims that eggs in mosses are fertilized by spores. What is wrong with that statement?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Besides springtails, are there other ways moss sperm may be transferred from male to female gametophytes?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Besides springtails, are there other ways moss sperm may be transferred from male to female gametophytes?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Animals are responsible for pollinating many flowering plants. Did animal-mediated fertilization originate with flowering plants, or was this mode of sperm dispersal likely in place before the origin of flowering plants? Explain.

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more. Animals are responsible for pollinating many flowering plants. Did animal-mediated fertilization originate with flowering plants, or was this mode of sperm dispersal likely in place before the origin of flowering plants? Explain.

In the life cycle of a fern, the multicellular male gametangium (the sex organ that produces sperm cells) is called a(n) __________.

To examine meiosis in ferns, you would study __________.

In the life cycle of ferns, the multicellular female gametangium (the sex organ that contains an egg) is a(n) __________.

The "dots" on the underside of a fern frond are spore cases; therefore, what is true of the plant to which the frond belongs?

Where would you find a fern gametophyte?

Fern gametophytes are __________.

In sporophyte ferns, the leaves are __________.

What is the evolutionary significance of megaphylls?

Vascular tissues of plants include __________.

The first large forests formed in the Carboniferous period. The decrease in CO₂ levels by all of these plants caused __________.

Microphylls are found in which plant group? a. lycophytes b. liverworts c. ferns d. hornworts

Soils, water, and the atmosphere are major components of the abiotic (nonliving) environment. Describe how green plants affect the abiotic environment in ways that are advantageous to humans.

Soils, water, and the atmosphere are major components of the abiotic (nonliving) environment. Describe how green plants affect the abiotic environment in ways that are advantageous to humans.

Which of the following adaptations is common to all seed plants?

Which one of the following is true of seed plants but not true of seedless plants?

The closest seedless relatives of seed plants produce one kind of spore that gives rise to a bisexual gametophyte. What does this suggest about the ancestors of seed plants?

The eggs of seed plants are fertilized within ovules, and the ovules then develop into __________.

The cells within pollen grains are __________ and together comprise the __________.

Besides the plant tissue that humans ingest, which angiosperm tissue is most directly important for human survival?

Six major crops˜wheat, rice, maize, potatoes, cassava, and sweet potatoes˜contribute disproportionately to human diets. What percentage of all the calories consumed by humans is supplied by these crops?

Which of the listed examples is evidence provided by living gymnosperms of an evolutionary transition between seedless and seed plants?

Which of the following best states the advantages that seeds have over spores?

Which gymnosperm phylum is characterized by large cones and fern-like leaves and thrived during the Mesozoic?

Dietary supplements and decongestants containing ephedrine have recently become more strongly regulated in the United States. Which phylum contains the plant from which ephedrine is extracted?

What global change occurring between the Carboniferous period and the Permian period likely contributed to the success of the gymnosperms?

What is located in the scalelike structures packed densely in pollen cones?

Each pollen grain of a gymnosperm contains a __________.

In ovulate cones, megasporocytes undergo __________ and produce __________ megaspores.

Which of the following lists of features characterizes eudicots?

In a typical conifer, how long does it take for fertilization to occur after pollination?

The diploid generation of the plant life cycle always __________.

Which types of angiosperms would most likely be wind-pollinated rather than animal-pollinated?

The vast majority of angiosperms with two cotyledons formerly classified as __________ are now classified as __________.

Like gymnosperms, many grasses and angiosperm trees are wind-pollinated. To conserve energy, these angiosperms do not produce complete flowers (complete flowers have all four of the basic parts). Which part would be unnecessary for wind-pollinated angiosperms?

The portion of a flower that receives the pollen is the __________.

In gymnosperms, the seed coat develops from the integument. In angiosperms, the seed coat develops from the __________.

During pollination, pollen grains are transferred from the __________ to the __________.

A pea pod is formed from __________. A pea inside the pod is formed from __________.

After fertilization, the __________ develops into a seed, and the __________ develops into a fruit.

Which of the following best describes the function of fruits?

A plant is said to be cross-pollinated if __________.

The triploid nucleus of the embryo sac develops into the __________.

The pollen tube releases two sperm cells into the embryo sac. The result of this is the __________.

Of the following, which is a difference in how reproduction occurs in gymnosperms compared to angiosperms?

Where in an angiosperm would you find a megasporangium? a. in the style of a flower b. enclosed in the stigma of a flower c. within an ovule contained within an ovary of a flower d. packed into pollen sacs within the anthers found on a stamen

Which of the following is a key feature of seed plants facilitating life on land? (A)homospory (B)pollen (C)reduced sporophytes (D)spores

Key features of seed plants facilitating life on land include three of the following four traits. Select the exception. a. homospory b. pollen c. reduced gametophytes d. seeds

With respect to angiosperms, which of the following is incorrectly paired with its chromosome count? a. egg—n b. megaspore—2n c. microspore—n d. zygote—2n

Angiosperms are different from all other plants because only they have a. a vascular system. b. flowers. c. seeds. d. a dominant sporophyte phase.

Which of the following is a characteristic that distinguishes gymnosperms and angiosperms from other plants? (A)alternation of generations (B)independent gametophytes (C)vascular tissue (D)ovules

Which of the following is not a characteristic that distinguishes gymnosperms and angiosperms from other plants? a. dependent gametophytes b. ovules c. pollen d. alternation of generations

Which of the following structures produce eggs and sperm? (Explain your answer.) a. fern sporophytes b. moss gametophytes c. the anthers of a flower d. moss sporangia

Gymnosperms and angiosperms have the following in common except a. seeds. b. pollen. c. ovaries. d. ovules.

The eggs of seed plants are fertilized within ovules, and the ovules then develop into a. seeds. b. spores. c. fruit. d. sporophytes.

The diploid sporophyte stage is dominant in the life cycles of all of the following except a pine tree. a rose bush. a fern. a moss.

DRAW IT Use the letters a–d to label where on the phylogenetic tree each of the following derived characters appears. a. flowers b. embryos c. seeds d. vascular tissue

Which of the following terms includes all the others? a. angiosperm b. gymnosperm c. vascular plant d. fern e. seed plant

Explain the difference between homosporous and heterosporous plants. Where are the microsporangium and megasporangium found in a tulip? What happens to the spores that are produced by these structures?

Explain the difference between homosporous and heterosporous plants. Where are the microsporangium and megasporangium found in a tulip? What happens to the spores that are produced by these structures?

Angiosperms such as grasses, oaks, and maples are wind pollinated. The ancestors of these subgroups were probably pollinated by insects, however. As an adaptive advantage, why might a species “revert” to wind pollination? (Hint: Think about the costs and benefits of being pollinated by insects versus wind.) Why is it logical to observe that wind-pollinated species usually grow in dense stands containing many individuals of the same species? Why is it logical to observe that in wind-pollinated deciduous trees, flowers form very early in spring—before leaves form?

Angiosperms such as grasses, oaks, and maples are wind pollinated. The ancestors of these subgroups were probably pollinated by insects, however. As an adaptive advantage, why might a species “revert” to wind pollination? (Hint: Think about the costs and benefits of being pollinated by insects versus wind.) Why is it logical to observe that wind-pollinated species usually grow in dense stands containing many individuals of the same species? Why is it logical to observe that in wind-pollinated deciduous trees, flowers form very early in spring—before leaves form?

You have been hired as a field assistant for a researcher interested in the evolution of flower characteristics in orchids. Design an experiment to determine whether color, size, shape, scent, or amount of nectar is the most important factor in attracting pollinators to a particular species. Assume that you can change any flower’s color with a dye and that you can remove petals or nectar stores, add particular scents, add nectar by injection, or switch parts among species by cutting and gluing.

Compare a seed plant with an alga in terms of adaptations for life on land versus life in the water.

You have been hired as a field assistant for a researcher interested in the evolution of flower characteristics in orchids. Design an experiment to determine whether color, size, shape, scent, or amount of nectar is the most important factor in attracting pollinators to a particular species. Assume that you can change any flower’s color with a dye and that you can remove petals or nectar stores, add particular scents, add nectar by injection, or switch parts among species by cutting and gluing.