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Explain the many kinds of liverworts?
Where do they really like it?
- i. There are leafy ones
- ii. The ones around here are very flat
- a. They like it really moist
- i. Best place to find some is along the street; often grow on rocks and streams
- 1. Like moisture
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Phylum?
How do they grow?
Form of reproduction?
Hepatophyta
- a. They grow by forming a fork
- i. The thallus forks
- 1. The older portion dies and the other two newer strsuctures of the fork continue propagation
- b. Asexual reproduction
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a. Structure of Thallus (p. 376-377; 369)
i. __
ii. Top part is __
iii. There are __ below for __
iv. There are __ that do what __and __(__)
- Gametophyte
- photosynthetic
- storage cells
- storage
- scales
- (trap water between scale and major part of plant)
- rhizoids (absorb)
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i. __ by layer of epidermis and layer above storage cells
1. __, which has __
a. The reason they tend to live in moist environments is because __; no way to __; very easy for plants to __
They also have __.
Which species are the most studied?
- Big space
- epidermis
- pores
- the pore is permanently open
- close it
- lose water
- gemmae cups
- marcantia
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a. Sexual Reproduction
i. Male and female plants
1. Male is __
2. Female is __
- antheridia; they have antheridiophores with anteridia in the top of the structure that is on a little stalk
- archegonia; they have archigoniophores with archegonia, which are on the other side and point downward
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a. Why is it pointing downward?
i. Because that’s the orientation because usually, when they are mature, the whole structure is down on the surface of the liverwort; the stalk doesn’t begin to elongate yet
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What is the advantage of the archegonia pointing downward?
i. Advantage: archegonia is pointing downward because it allows a small amount of water to allow the sperm to swim down to the egg since they are flagellated
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i. Once the egg has been fertilized, then what happens?
1. The sporophyte has a __that is embedded in the __; the __; the __
- the stalk elongates
- foot
- tissue of the gametophyte
- stalk
- capsule
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i. Why is it important for the structure to be at the top of the long stalks; the capsules pointing downward?
1. The spores in the capsule (which develops a pore to open up) can be dispersed; if it were on the bottom, it wouldn’t be able to get dispersed
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i. These capsules have __, which moss don’t
1. They are sensitive to __and will do what to help __
a. Hopefully, there’s enough wind to carry it away
- elaters
- humidty
- twist with changes
- in humidity
- throw the spores out
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Asexual reproduction
1. Forms cups on the surface called __ (kind of __)
2. Eventually form __, which will become gametophytes
3. No __stage
- gemmae cups
- fragmentation
- gemma
- protonemous
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1. In the case of mercantia, there are __ and __. Explain the female.
male and female gametophytes
- a. Archegonia are on the underside of the structure (pointing downward) i. Venter, neck, one egg ii. One of the structures will produce numerous archegonia
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Explain the male.
- a. ON the male gametophyte, the top contains antheridia
- i. Sterile layer of cells on outside; all cells can develop into sperm
- ii. any antheridia will produce numerous sperm
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1. How do sperm get from male thallus to female thallus (plant to plant); and, then after, how do they get to the antheridia?
- a. Water (raindrops)
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i. Splashed on by raindrops
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Where is archegonia located?
How do sperm get from where they are to where the antheridium is?
After fertilization, what happens?
Archegonia is up top on the underside
- Because antheridia are relatively short,
a. What you tend to find is that, when fertilization happens, the stalk is not very tall; the top is basically sittin on the surface of the gametophyte; that’s why they are on the underside - a.
Then, the stalk elongates- i. But, its fertilization, then stalk elongation
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1. What is the advantage of the top part (A in the diagram) being up top with the top of the female reproductive structure pointing downward?
- a. Dispersal by the wind
- b. If it were lying on the top, they would fall to the bottom
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What do they respond to?
- 1. They twist in response to humidityà throw the spores out
- a. More chance of being dispersed
- b. They twist with the change in humidy
- i. They may twist a little bit more when it’s getting drier
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Explain the spacing of the reproductive structures.
- 1. Male reproductive structures are flat on top; rather scalloped
- 2. The archegonium are spaced around (resemble the spokes of an umbrella)
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