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Chapter 22
Introduction to the Plant Kingdom: Bryophytes
CHAPTER OUTLINE
Evolution of plants
The plant kingdom
The plant life cycle alternates between haploid and diploid generations
Four major groups of plants evolved
Plants and the Environment: The Environmental Challenges of Living on Land
CHAPTER OBJECTIVES
1. Discuss some environmental challenges of living on land and describe how several plant
adaptations meet those challenges.
LECTURE OUTLINE
I. The earliest plants evolved over 400 million years ago.
A. What kind of plant was the probable ancestor of plants?
B. What characteristics do plants share with green algae?
1. Photosynthetic pigments
adaptive significance of these differences?
III. What are the differences between the nonvascular plants and vascular plants?
IV. Describe alternation of generations.
A. What reproductive cells are produced by the gametophyte?
1. What type of cell division produces gametes?
V. What are the bryophytes?
A. What is a typical habitat for bryophytes?
B. Which is the dominant generation in bryophytes?
C. What are the mosses?
1. Why are their rootlike, stemlike, and leaflike structures not simply called roots, stems,
and leaves?
2. What are rhizoids?
3. What are the characteristics of a typical moss gametophyte?
2. How are hornworts different from mosses and liverworts?
3. Compare the reproductive structures of hornworts to those of mosses and liverworts.
4. What is unique about the hornwort sporophyte?
VI. Where do bryophytes fit in the evolutionary tree?
KEY TERMS
alternation of generations,
p. 431
antheridium, p. 432
gametophyte generation,
p. 432
gemmae, p. 439
spore mother cell, p. 432
sporophyte generation,
p. 432
TEACHING TIPS
1. Be sure to emphasize the care needed when using traditional terms to compare plant
groups. As noted in the text on page 434, the terms lower and higher, and primitive and
advanced are not meant to imply any superiority of one type over the other. Primitive
2. Spore dispersal in mosses can be demonstrated in lecture using an overhead projector or a
dissecting microscope with a micro-video camera. As the sporangia dry out, the spores
3. Discuss the statement “mosses only grow on the north side of trees.” Would this be true
in the Southern Hemisphere?