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.