Bryophytes

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Bryophytes

• I. Intro
• A. Phyla
• B. Evolution
• C. Ecology
• D. Life cycles
• II. Mosses
• III. Liverworts
• IV. Problems of land plants - Bryophyte solutions

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Bryophytes
I. Introduction A. Phyla 1. Liverworts
(Hepatophyta) 2. Hornworts (Anthocerophyta) 3.
Mosses (Bryophyta) 3 Classes of
mosses Sphagnidae (Sphagnum
mosses) Andreaeidae (granite
mosses) Bryidae (true mosses)
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I.B. Evolutionary connections
1. Origin from green algae 2. Mosses most closely
related to vascular plants
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I. B. 3. Obstacles to land life
a. Dessication i. Of plant ii. Of spores iii.
Of gametes b. Resource acquisition c. Light
acquisition i. Fight gravity ii. Fluid transport
d. No water for reproduction i. Gamete
dispersal ii. Spore dispersal e. Harsher
environment i. More intense light ii. Greater
temp. fluctuations
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I. C. Interesting ecology
1. Ground cover 2. Carbon cycle
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I. C. Interesting ecology
3. Epiphytes 4. Peat moss (Sphagnum)
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I. D. Life cycle of Bryophytes
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II. Mosses (Bryophyta)
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Capsule and peristome teeth
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III. Hepatophyta - The Liverworts
A. Much (e.g., life cycle) is similar to Bryophyta
B. Differences
1. Growth forms
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B. Differences
2. Asexual reproduction - gemmae cups
Fig. 18-15
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B. Differences
3. Spore dispersal - elators vs. peristome teeth
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B. Differences
4. No primitive conducting tissues, as in mosses
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IV. Obstacles to land life Bryophyte solutions
A. Desiccation i. Of plant - ii. Of spores
- iii. Of gametes -
Little waterproof covering, primitive stomata,
but can survive desiccation.
Waterproof sporopollenin - very tough.
Some protection in antheridia and archegonia,
but sperm still need water to get to archegonium.
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IV. Obstacles to land life Bryophyte solutions
B. Resource acquisition - water and minerals
No true roots
Direct absorption through all cells
Disadvantage - can only grow when wet Advantage
- dont need soil
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IV. Obstacles to land life Bryophyte solutions
C. Support to fight gravity - for light
acquisition, spore or gamete dispersal
NOT MUCH!
- Primary cell walls only, some turgor support
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IV. Obstacles to land life Bryophyte solutions
C. Fluid transport - caused by growing up
NOT MUCH!
- hydroids and leptoids in moss sporophyte
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IV. Obstacles to land life Bryophyte solutions
E. No water for reproduction i. For gametes
- ii. For spores -
Water still needed for sperm to get to egg.
Spores dispersed by wind
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