Download Lesson Objectives Ch

Ch. 12 Altermation of generation/plant life cycles
A. Haploid and Diploid generations alternate in plant life cycles
1. Plant reproduction occurs asexually and sexually.
2. Alternation of generations
3. sporophyte
4. gametophyte
5. spores
6. gametes
B. Review generalized diagram of alternation of generations
1. Fertilization marks the beginning of the diploid part of the life cycle
2. Meiosis begins the haploid phase of the life cycle
C. Comparison of life cycles for algae, bryophytes, vascular plants
1. Evolutionary trend toward diploid dominance during colonization of land
D. Life Cycle of Polytrichum, a Species of Moss
1. Gametophytes
2. flagellated sperm
3. zygote
4. Sporophytes remain
5. spores released
E. Ferns have a dominant sporophyte
1. sporophyte
2. spores released and develop into gametophyte by mitosis
3. gametophyte
4. fern zygotes remain in female gametangium
5. sporangia in clusters on fern’s underside
F. Seedless plants formed "coal forests"
1. tropical swamp forests
2. remains formed peat
3. swamps
4. coal
G. Life Cycle of Ponderosa Pine
1. Sporophyte
2. Pine trees and other conifers
3. The gametophyte generation
4. female cone
5. Male cones
6. months later, pollen tube releases a nonflagellated sperm
7. Seed formation
8. Summary
Lesson Objectives Ch. 12
Haploid
Diploid
Alternation of Generations
Sporophyte
Gametophyte
Spores
Gametes
Meiosis
Mitosis
Lesson Objectives:
1. Draw/label and explain alternation of generations in gymnosperms using the terms
above.
2. What are the 4 main plant groups? What are the essential evolutionary contributions
of each group?
3. What group(s) has a dominant gametophyte stage? Why is the dominance in
gametophyte stage, unusual for a land plant, thought to exist in the group(s)?
4. Which groups have a dominant sporophyte stage? Why is dominance more prevalent
in most plants in the sporophyte stage?