Chapter 29 Practice problems and quiz problems

Question 1

The most direct ancestors of land plants were probably ________.

Question 1 options:

photosynthesizing prokaryotes (cyanobacteria)

kelp (brown alga) that formed large beds near the shorelines

green algae

liverworts and mosses

Answer 1

green algae

Question 2

About 450 million years ago, the terrestrial landscape on Earth would have ________.

Question 2 options:

had non-vascular, green plants similar to liverworts forming green mats on rock

been completely bare rock, with little pools that contained cyanobacteria and protists

looked very similar to that of today, with flowers, grasses, shrubs, and trees

been covered with tall forests in swamps that would become today’s coal

Answer 2

had non-vascular, green plants similar to liverworts forming green mats on rock

Question 3

Why have biologists hypothesized that the first land plants had a low, sprawling growth habit?

Question 3 options:

Land animals of that period were small and could not pollinate tall plants.

The ancestors of land plants, green algae, lacked the structural support to stand erect in air.

There was less competition for space, so they simply spread out flat.

They were tied to the water for reproduction, thus needing to remain in close contact with the moist soil.

Answer 3

The ancestors of land plants, green algae, lacked the structural support to stand erect in air.

Question 4

You find a green organism in a pond near your house and believe it is a plant, not an alga. The mystery organism is most likely a plant and not an alga if it ________.

Question 4 options:

does not contain vascular tissue

contains chloroplasts

is surrounded by a cuticle

has cell walls that are comprised largely of cellulose

Answer 4

is surrounded by a cuticle

Question 5

A student encounters a pondweed that appears to be a charophyte. Which of the following features would help the student determine whether the sample comes from a charophyte or from some other type of green alga?

Question 5 options:

molecular structure of enzymes inside the chloroplasts and presence of phragmoplasts

structure of sperm cells, presence of phragmoplasts, and rings of cellulose-synthesizing complexes

molecular structure of enzymes inside the chloroplasts and rings of cellulose-synthesizing complexes

structure of sperm cells and presence of phragmoplasts

Answer 5

structure of sperm cells, presence of phragmoplasts, and rings of cellulose-synthesizing complexes

Question 6

The presence of vascular tissue allowed plants to ________.

Question 8 options:

absorb nutrients from the soil and form a symbiosis with fungi

transport nutrients and water from below-ground tissues and use them to protect developing embryos

release toxins into the soil that reduce competition with other plants by poisoning nearby plants

transport nutrients and water from below-ground tissues to above-ground tissues and grow taller

Answer 6

transport nutrients and water from below-ground tissues to above-ground tissues and grow taller

Question 7

Liverworts, hornworts, and mosses are grouped together as bryophytes. Besides not having vascular tissue, what do they all have in common?

Question 9 options:

They require water for reproduction.

They are heterosporous.

They can reproduce asexually by producing gemmae.

They are all wind-pollinated.

Answer 7

They require water for reproduction.

Question 8

A botanist discovers a new species of plant in a tropical rain forest. Investigation of its anatomy and life cycle shows the following characteristics: flagellated sperm, xylem with tracheids, separate gametophyte, and sporophyte generations with the sporophyte dominant, and no seeds. This plant is probably most closely related to ________.

gymnosperms

flowering plants

mosses

ferns

Answer 8

ferns

Question 9

Why do researchers identify the charophytes rather than another group of algae as the closest relatives of plants?

Answer 9

Plants and charophytes share key traits - they both have rings of cellulose-synthesizing complexes, sperm structure similarity (flagellated sperm), and they both form phragmoplasts in cell division. Genetic analysis of mitochondria/nuclear/chloroplast DNA of Zygnema and Coleochaetes indicate close genetic similarity with plants

Question 10

Identify four derived traits that distinguish plants from charophyte green algae and facilitate life on
land.

Answer 10

1. Spore walls are toughened by sporopellenin (protects from environment)
2. Multicellular, dependent embryos
3. Stomatas (which control gas exchange and reduce water loss)
4. Presence of cuticle (which reduces water loss and aids in protection)

Question 11

What would the human life cycle be life if we had alternation of generations? Assume that the multicellular diploid stage would be similar in form to an adult human.

Answer 11

Multicellular diploid adult stage would not produce gametes like usual. Instead both males and females would produce haploid spores through meiosis.

This would give rise to both male and female haploid multicellular stages, which are much different than the single-cell haploid stages of sperm and egg cells. Multicellular haploid (gametophyte) stages would then produce gametes which would reproduce sexually

Question 12

How do bryophytes differ from other plants?

Answer 12

Most bryophytes do not have vascular transport systems (vascular tissue) and their life cycles are dominated by the gametophyte stage and not the sporophyte stage

Question 13

Could the effects of global warming on peatlands alter CO2 concentrations in ways that result in negative or positive feedback? Explain.

Answer 13

Positive feedback (in which the end product of a process increases its own production)

Global warming will lower the water level in some peatlands, home of peat mosses. This will expose peat to air and cause them to decompose, thus releasing CO2 into the atmosphere. Since CO2 is a greenhouse gas, this will cause increased levels of global warming –> lower water level more –> cause more peat to decompose and release more CO2

Question 14

List the key derived traits found in monilophytes and seed plants but not in lycophytes.

Answer 14

1. Lycophytes have microphylls, while seed plants and monilphytes have megaphylls
2. Initiation of new root branches at various points along an existing root - this phenomenon is not found in lycophytes.

Question 15

If fertilization occurred between gametes from one gametophyte, how would this affect the production of genetic variation from sexual reproduction?

Answer 15

If fertilization occured between the gametes of only one gametophyte, it would decrease genetic variation because genetic variation arises from sexual fertilization of gametes between two gametophytes, and genetic information is scrambled via this fertilization, independent assortment of genes, and crossing over.

This lack of genetic variation would cause evolution in the population to slow or stop altogether

Question 16

What trait(s) allowed vascular plants to grow tall, and why might increased height have been advantageous?

Answer 16

Vascular plants have vascular tissue (xylem and phloem) that allow them to grow tall while providing structural support, while also allowing nutrients gathered by roots to be transported up the stem or trunk to the rest of the plant. Roots also provide an anchoring presence and gather nutrients needed by the rest of the plant.

Height will be advantageous in a forest setting because taller plants will shade out the shorter plants, making height advantageous. Also, taller plants may be more successful reproductively because they can disperse their spores farther than short plants