Principles of Biology - Biology 102
Spring Quarter
Lake Tahoe Community College
Instructor: Sue Kloss
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Ch. 30 - Evolution of Seed Plants
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I. Reduced gametophytes of seed plants
A. Advantages of reduced gametophytes
1. mosses have more important gametophyte stages
2. gametophytes of seed plants are mostly microscopic
3. tiny gametophytes can develop from spores
B. Heterospory
1. nearly all seedless plants are homosporous
2. At some point, seed plants became heterosporous
C. Ovules and production of eggs
1. seed plants retain megaspore
2. integuments
3. megasporangium,
4. female gametophyte develops
D. Pollen and production of sperm
1. microspores
2. pollen
3. dispersal
4. transfer of pollen
E. Evolutionary advantages of seeds
1. a seed = kid, coat, lunch box
II. Gymnosperms bear “naked” seeds
Conifers = cone-bearing
A. Gymnosperm diversity
1. Cycadophyta
2. Ginkgophyta
3. Gnetophyta
4. Coniferophyta
B. Gymnosperm evolution
1. Conifers
2. Lycophytea
3. food supply of giant herbivorous dinosaurs
4. climate gradually cooled
C. Pine Life Cycle
III. Reproductive adaptations of angiosperms include flowers and fruits; angio = Gr. vessel - ovary;
A. Flowers
1. pollination
2. flower
B. Fruits - mature ovary
1. fruit
2. fruit devel.
3. pericarp
4. fruits help dispersal
C. Angiosperm Life cycle
D. Angiosperm diversity
1. Monocots
2. dicots
E. Evolutionary links between angiosperms and animals
1. animals
2. coevolution
IV. Human welfare depends greatly on seed plants
A. Products from seed plants
B. Threats to plant diversity
1. deforestation
2. potential medicines,
3. food crops
Ch. 30 Objectives
1. Name five terrestrial adaptations that contributed to the success of seed plants.
2. Compare the size and independence of the gametophytes of bryophytes with those of seed plants.
3. Describe the ovule of a seed plant.
4. Contrast the male gametophytes of bryophytes with those of seed plants.
5. Explain why pollen grains were an important adaptation for successful reproduction on land.
6. Compare spores with seeds as dispersal stages in plant life cycles.
7. List and distinguish among the four phyla of gymnosperms.
8. Describe the life history of a pine. Indicate which structures are part of the gametophyte generation and which are
part of the sporophyte generation.
9. Identify the following floral structures and describe a function for each:
a. sepal
f. anther
b. petal
g. stigma
c. stamen
h. style
d. carpel
i. ovary
e. filament
j. ovule
10. Define fruit. Explain variations in how fruits may be adapted to disperse seeds.
11. Explain why a cereal grain is a fruit rather than a seed.
12. Diagram the generalized life cycle of an angiosperm. Indicate which structures are part of the gametophyte
generation and which are part of the sporophyte generation.
13. Describe the role of the generative cell and the tube cell within the angiosperm pollen grain.
14. Explain the process and function of double fertilization.
15. Distinguish between monocots and eudicots.
16. Explain how animals may have influenced the evolution of terrestrial plants and vice versa.