Chapter 29     Plant Diversity I: Colonization of Land

Objectives

An Overview of Land Plant Evolution
1. Describe four shared derived homologies that link charophyceans and land plants.
2. Distinguish among the kingdoms Plantae, Streptophyta, and Viridiplantae. Note which of these is used in the textbook.
3. Describe five characteristics that distinguish land plants from charophycean algae. Explain how these features are adaptive for life on land.
4. Define and distinguish among the stages of the alternation of generations life cycle
5. Describe evidence that suggests that plants arose roughly 475 million years ago.
   
  Bryophytes
6. List and distinguish among the three phyla of bryophytes. Briefly describe the characteristics of each group.
7. Distinguish between the phylum Bryophyta and the bryophytes.
8. Explain why bryophyte rhizoids are not considered roots.
9. Explain why most bryophytes grow close to the ground.
10. Diagram the life cycle of a bryophyte. Label the gametophyte and sporophyte stages and the locations of gamete production, fertilization, and spore production.
11. Describe the ecological and economic significance of bryophytes.
   
  The Origin and Diversity of Vascular Plants
12. Describe the five traits that characterize modern vascular plants. Explain how these characteristics have contributed to their success on land.
13. Distinguish between microphylls and megaphylls.
14. Distinguish between the homosporous and heterosporous condition.
15. Explain why seedless vascular plants are most commonly found in damp habitats.
16. Name the two clades of living seedless vascular plants.
17. Explain how vascular plants differ from bryophytes.
18. Distinguish between giant and small lycophytes.
19. Explain why whisk ferns are no longer considered to be “living fossils.”
20. Describe the production and dispersal of fern spores.
   
  Student Misconceptions
21. Many students have difficulty in understanding the significance of derived characters that are shared between two extant groups. Just as many members of the general public have the mistaken notion that humans evolved from chimpanzees, some students will think that charophyceans are in some sense ancestral to plants or that charophyceans are identical to the last common ancestor that plants and charophyceans shared.
22. It is important to make sure that your students understand alternation of generations in bryophytes and seedless vascular plants. Plant life cycles are challenging for all students. Without a good understanding of the life cycles of plants with recognizable gametophytes and sporophytes, students will have great difficulty with gymnosperm and angiosperm life cycles.
23. Students tend to think of derived traits as “advanced.” Be careful to avoid this term. Point out that organisms have a combination of primitive and derived traits, and that all living organisms have an equally long evolutionary history, dating back to the origin of life on Earth.
24. Many students are not very familiar with or knowledgeable about plants. Some of the terminology of plant life cycles can be confusing to such students. Clarify for students the meaning of these pairs of terms:
a. homosporous and heterosporous
b. bryophyte and phylum Bryophyta
c. rhizoid and root
   

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