Biology 1A Nov 17, 1998
Lecture 21 - Gymnosperms
Page Contents :
Reading Assignment:
Overview of Lecture:
Review of pteridophyte groups.
Progymnosperms.
Cycads.
Ginkgos.
Conifers.
Lecture Outline:
I. Review of pteridophyte groups.
II. Progymnosperms.
III. Cycads.
IV. Ginkgos.
V. Conifers.
Vocabulary:
Archaeopteris dioecious resin
aril Ginkgo biloba resin canal
bract gymnosperm scale
butyric acid monoecious seed
cone ovule seed cone
conifer pollen cone stroblius
cycad progymnosperm
Study Questions:
- In the 1950s, the fossil leaves of Archaeopteris were found attached to fossil wood of Callixylon. Why was this so significant?
- What kind of life cycle did progymnosperms have? Were they seed plants?
- How many groups of gymnosperms are there today? What are they?
- How does the wood of gymnosperms differ from that of angiosperms? Give two specific ways.
- Which gymnosperms are always dioecious? Which may be monoecious?
- How is being dioecious different from being dioicous?
- Describe the overall structure of a cycad, including both stems and leaves. How is this different from a typical conifer? How is it like a palm? How are cycads different from palms?
- Coralloid roots in cycads are a symbiotic relationship with what other group of organisms? How does the cycad benefit from the relationship? How does the other organism benefit?
- How many species of Ginkgo are there alive today? Where does Ginkgo grow naturally in the wild?
- Why is Ginkgo such a popular ornamental tree in cities? Why are the seed trees less popular than the pollen trees?
- Conifers get their name from the cones they bear. Do all conifers bear cones? Explain.
- Do cycads produce cones? Do ginkgos?
- How is the pollen cone of a pine tree like the stroblius of a club moss? How is it different?
- Describe the structure of a seed cone in pine. How do we know that the seeds are attached to modified branches and not to modified leaves?
- What are resin canals? What functions does resin serve in gymnosperms?
- What shape is conifer pollen?
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