Bio Ch.26

Modern coal deposits formed from plants that were present during the Carboniferous period, approximately ______ years ago.

350 million

Plants started growing on land approximately _______ years ago.

450 million

What is a monilophyte?

A clade of seedless vascular plants that includes ferns and horsetails

Which part of the moss life cycle is paired with an incorrect description?

Archegonium: specialized organ on the gametophyte that produces spores

Which synapomorphies support stoneworts as the closest sister group of land plants?

Branching and apical growth

Which of the nonvascular plant clades has the highest number of extant species?

Bryophyta (mosses)

Which statement about plant life cycles is true?

Homosporous plants evolved before heterosporous plants.

Where on a fern plant would you look to find spores?

In clusters of sporangia in sori on the sporophyte leaf

Which set of clades correctly describes the nonvascular land plants?

Liverworts, mosses, and hornworts

Which living group was the earliest to evolutionarily diverge from all other living vascular plants?

Lycophytes (club mosses, spike mosses, and quillworts)

The hornworts are the sister taxon of which other land plant clade(s)?

Lycophytes, horsetails, ferns, and seed plants

True roots are a synapomorphy of which of the following groups of plants?

Lycophytes, monilophytes, seed plants

With this in mind, which description best summarizes the ancestor of plants?

Primary endosymbiosis by a unicellular eukaryote resulted in the engulfment of a photosynthetic bacterium that over time became the chloroplast.

Which of the following was not involved in soil formation on the early land masses?

Products of photosynthesis

Homosporous plants bear a single type of spore that gives rise to one type of gametophyte. Heterosporous plants produce two types of spores resulting in two distinct gametophytes—one male and one female. What is a plausible explanation for the evolution of separate male and female gametophytes in heterosporous plants?

Separating male and female gametophytes promotes outcrossing and results in greater genetic diversity of offspring.

Which is the correct order of development in a moss gametophyte?

Spore, branched filamentous protonema, bud, spiral leafy gametophyte, gametangia

Which statement about alternation of generations in land plants is true?

The gametophyte produces haploid gametes by mitosis.

Which statement provides the most accurate description of the structures shown in the figure?

These structures contain small, lens-shaped outgrowths that are capable of asexually propagating liverworts.

Why do ferns often grow in moist habitats? However, as in nonvascular plants, fern reproduction does require water.

They have flagellated sperm that require liquid water to swim to the egg.

Why is liquid water required for sexual reproduction in mosses?

They have sperm with flagella.

Based on its appearance, which of the following is true?

This alga uses chlorophyll a and phycoerythrin to obtain energy from the sun.

Which statement best describes the hypothesis for why high atmospheric CO2 limited evolution of large megaphylls?

With high CO2, fewer stomata were needed, so the plants had less capacity for evaporative cooling of large leaves.

What does the figure show?

a cluster of spores

With regard to the life cycles observed in plants and animals, the two groups share the similarity of

a generation of multicellular diploid individuals.

Two hallmarks of a life cycle with an alternation of generations are

a multicellular diploid stage and multicellular haploid stage, and gametes that are produced by mitosis.

Dichotomous branching happens when

a shoot tip divides and grows into two equal branches

Coleochaetophytes have all of the following synapomorphies in common with stoneworts except

apical growth.

Algae

are aquatic photosynthetic eukaryotes.

Megaphyll size increased as _______ on Earth.

atmospheric CO2 decreased

In mosses, the protonema resembles filamentous green algae because

both are composed of branched photosynthetic filaments.

Despite being the largest clade of green algae, _______ are not believed to have given rise to land plants.

chlorophytes

The lycophyte group of plants includes

club mosses, spike mosses, and quillworts.

A strobilus is

compact cluster of spore-bearing microphylls

Stomata function to

control the entry and exit of O2, CO2, and water vapor from the plant surface.

The addition of tracheid cells strengthened with lignin allowed early land plants to do all of the following except

disperse gametes more widely.

Evolution of lignified cell walls contributed to the increased abilities of plants to

disperse spores, grow tall, and compete for sunlight.

You have discovered a new plant specimen that is simple in structure, much like an early land plant. To determine whether it was a tracheophyte and not one of the other land plants, you would look for

fluid-conducting cells called tracheids.

An archegonium is _______ and produces _______.

haploid; an egg

Rhyniophytes were characterized by

horizontal rhizomes, rhizoids, dichotomously branching aerial stems, and sporangia

Unlike the other groups of nonvascular plants, the _______ sporophyte has no stalk and is persistently green—a trait shared with vascular plants.

hornwort

Presence of stomata is a synapomorphy of

hornworts, mosses, and seed plants.

Which characteristic of nonvascular plants has restricted their expansion to moist areas on land?

lack of true roots

Liverworts can be distinguished from the other nonvascular plants because they

lack stomata

A megaspore is generally _______ a microspore.

larger than

Compared to the aquatic habitat, all of the following were environmental challenges to plants moving onto land except

low light conditions

Megaspores mature into _______, and microspores mature into _______.

megagametophytes; microgametophytes

Microphylls differ from megaphylls in that

microphylls are thought to have evolved from sterile sporangia, whereas megaphylls evolved from modified branches.

A megasporangium has the same relationship to a megaspore as a microsporangium has to a

microspore

Plant gametophytes divide by _______ to produce gametes, while sporophytes produce spores through _______.

mitosis; meiosis

The primary endosymbiosis of a cyanobacterium by an early eukaryotic cell that led to evolution of plants occurred _______ years ago.

more than a billion

Liverworts, hornworts, and mosses are found on all seven continents. Their survival in harsh environments is aided by

mycorrhizae

A growth pattern that contributed to evolution of megaphylls is

overtopping

Growth of red algae in deep water is most limited by

penetration of light through the water.

The red color present in red algae is primarily due to the accessory pigment

phycoerythrin.

Hornworts can be distinguished from the other nonvascular plants by their

single chloroplast per cell and persistently green sporophyte.

Specialized reproductive organs on the sporophyte are _______ that produce _______ by _______.

sporangia; spores; meiosis

Heterospory in a plant life cycle is characterized by two different kinds of

spores that mature into two different kinds of gametophytes.

In nonvascular plants, the _______ is usually nonphotosynthetic and is _______ dependent on the _______.

sporophyte; nutritionally; gametophyte

In recent years, atmospheric levels of CO2 have increased, resulting in global temperature change. With regard to leaf structure, this increase in CO2 could mean less selective pressure for _______, which would ultimately drive selection for a reduction in leaf area.

stomata

In addition to the various synapomorphies present in the _______, the most compelling evidence that they are the sister group to the land plants is based on gene sequences.

stoneworts

A(n) _______ is defined as a shared derived trait.

synapomorphy

Land plants are often called embryophytes because

the embryo is protected by the parent plant.

The evolution shown in the figure is best described as

the flattening of a branching sporophyte characterized by overtopping that would eventually develop into a megaphyll.

The feature that distinguishes hornworts as more closely related to vascular plants than mosses or liverworts is

the presence of a nutritionally independent sporophyte.

In the fern life cycle,

the sporophyte is larger and longer-lived than the gametophyte.

Despite lacking tracheids, nonvascular plants possess structures or characteristics that allow them to obtain and transport water and minerals on land. These include all of the following except

thick spore walls to prevent desiccation.

The common ancestor of vascular plants had

tracheids

Xylem and phloem are both types of

vascular tissue

The earliest clades of photosynthetic eukaryotes that led to land plants

were similar to the modern glaucophytes, red algae, and chlorophytes.