Chapter 27: Plants without seeds from water to land (learning curve)

Modern coal deposits formed from plants of the Carboniferous period that grew approximately ______ years ago.

350 million

Plants started growing on land approximately

450 million years ago.

What is a monilophyte?

A clade of seedless vascular plants that includes ferns and horsetails

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

Branching and apical growth

Scientists have recently begun exploring green algae as a source of biofuels. Which is not a reason these photosynthetic eukaryotes are attractive targets for petroleum production?

Efficient growing facilities have already been established.

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

In clusters of sporangia in sori on the sporophyte leaf

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

Lycophytes (club mosses, spike mosses, and quillworts)

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

Lycophytes, monilophytes, seed plants

Which set of clades correctly describes the tracheophytes?

Lycopodiophyta, monilophyta, cycadophyta, ginkgophyta, gnetophyta, coniferophyta, and angiosperms

Which structure in land plants is haploid?

Multicellular gametophyte

The organism shown is thought to be similar in form to the ancestor of the Plantae. 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 structure in land plants is diploid?

Sporangium

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

The gametophyte produces haploid gametes by mitosis.

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.

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.

Megaphyll size increased as _______ on Earth.

atmospheric CO2 decreased

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

chlorophytes

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.

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

gametangia; gametes; mitosis

In nonvascular plants, the _______ is photosynthetic and is _______ independent of the _______.

gametophyte; nutritionally; sporophyte

If you examined Sphagnum peat under the microscope, you might see partially decomposed Please choose the correct answer from the following choices, and then select the submit answer button.

gametophytes and spores.

An archegonium is _______ and produces _______.

haploid; an egg

Structures found in individuals with a _______ life cycle include microgametophytes and megagametophytes.

heterosporous

Presence of stomata is a synapomorphy of

hornworts, mosses, and seed plants.

You recover a fossil from the Devonian period that appears to be a large sporophyte with a stem that grows in segments above whorls of true leaves. Based on this description, you identify the specimen as a _______, which is one member of a clade containing only itself and ferns.

horsetail

Chlorophytes

include both unicellular and multicellular forms.

The "plant" group

is defined differently by different groups of scientists.

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

lack of true roots

A megaspore is generally _______ a microspore.

larger than

Which of the land plant groups is considered to be the sister group of all the others?

liverworts

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

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

more than a billion years ago

Growth of red algae in deep water is most limited by

penetration of light through the water.

The cuticle was one of the most important adaptations to life on land for plants because it

protected the plant from desiccation.

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

In recent years, atmospheric levels of CO2 have increased and resulted in a 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

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

Soil formation on the early land masses was not helped by

the products of photosynthesis.

In the fern life cycle,

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

Sporophytes and gametophytes differ from each other genetically because

the sporophytes have one set of chromosomes from each parent, while gametophytes have only one set of chromosomes.

Why is liquid water required for sexual reproduction in mosses?

they have sperm with flagella

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 dessication.

The common ancestor of vascular plants had

tracheids

The earliest clades of photosynthetic eukaryotes that led to land plants

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

The nonvascular plant that could most easily spread and form a larger colony is one with a sporophyte that has a sporangium

with a long stalk and a mechanism to throw its spores.