Biology 1A Nov 17, 1998
Lecture 21 - Gymnosperms
Page Contents :
Overview of Lecture:
Review of pteridophyte groups.
I. Review of pteridophyte groups.
Archaeopteris dioecious resin
aril Ginkgo biloba resin canal
bract gymnosperm scale
butyric acid monoecious seed
cone ovule seed cone
conifer pollen cone stroblius
- 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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