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8 Cards in this Set
- Front
- Back
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Name three forces that helped contour the planet.
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a. Frost and rain
b. Snow and Ice c. Volcanic explosions |
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Identify the first plants that made the move to land
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Simple algae that had developed cell walls thick enough for them to survive on moist boulders and gravels
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What was a major problem that faced plants when they moved to land? How did mosses and liverworts resolve this problem?
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Major problem that plants faced when they moved to land was question of support.
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Name the two methods of reproduction found in the algae
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a. Budding
b. Sexually |
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Why do algae and the primitive land plants (mosses, liverworts) require water for reproduction?
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Algae and primitive land plants (mosses and liverworts) sexual method involved sex cells that swam through water to find one another and fuse
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Describe sexual reproduction in the liverworts. What is formed by the spores?
When are spores released? |
Liverworts produce two kinds of sex cells. These outgrowths only a few cm high develop tiny mobile sperms that actively swim. The different growths contain larger cells, the eggs. When the outgrowths are ripe and conditions sufficiently wet, fertilization begins. The sperm finds the female organ and the eggs develop repeatedly dividing to produce a capsule full of microscopic grain: spores when they are ripe and the weather is dry the capsule burst, each spore is capable of growing into a new liverwort plant.
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Mosses and liverworts have two generations: sexual and asexual
a. What is the function of the sexual generation? b. What is the function of the asexual generation? |
Function of the sexual generation is to provide the variety of offspring necessary for continued evolution
Function of the asexual generation can be carried on the wind to distribute the plant over great distances |
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Describe the spore capsules of mosses.
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Spore capsules of mosses are varied in shape, and they have ways of making sure they only release their contents when the weather is warm and dry. Many have detachable caps that are blown off so the spores can be released and the wind will carry the spores for miles
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