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11 Cards in this Set
- Front
- Back
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In what period of Earth’s history do we believe that vascularization emerged?
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The first fossil record of a vascular plant is from the Silurian period, about 420 million years ago. Seedless vascular plants went on to dominate the land through the Carboniferous period, about 300 million years ago.
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What advantages does vascular tissue give plants?
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Vasculature provides a means for fluid transport and structural support for the body of the plant.
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What are the two types of vascular tissue? What do each of them transport?
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Vascular tissue consists of xylem and phloem. Xylem is primarily the vasculature where water and minerals travel from the roots up the stems to the various parts of the plant. Phloem transports the sugars made during photosynthesis down to the roots for energy.
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What molecule gives vascular plants support? How does it do this?
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Vascular tissue gives support to plants. Lignin is embedded in plant cell walls between the cellulose matrix, and it is a very stable molecule that does not break down easily. We are able to use wood in construction because of the strength that lignin provides. Lignin plays the same role in plants.
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What types of spores are involved with the moss life cycle? What is this condition called, and how do these spores develop.
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The moss life cycle is characterized by two types of haploid spores (male and female), a condition called heterosporous. In this case, the sporophyte produces (via meiosis) megaspores and microspores. Haploid megaspores develop into haploid female gametophytes, which then produce eggs. Likewise, haploid microspores develop into male gametophytes, which then produce sperm. Haploid gametes then join to form sporophytes.
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How are seedless vascular plants different in spore production? How does this change the gametophyte generation? How do the gametes join?
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In seedless vascular plants, both the heterosporous condition described above and the homosporous condition result in a single type of spore that develops into bisexual gametophytes. Bisexual gametophytes can produce both male and female gametes (eggs and sperm). Note, eggs and sperm are still separate and must join during fertilization, just as in the heterosporous condition.
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What is the dominant generation of a fern?
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The sporophyte is the dominant generation.
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Draw and describe the life cycle of a fern as an example of a seedless vascular plant. Use the proper terminology and show the ploidy levels of each structure and generation.
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Draw and describe the life cycle of a fern as an example of a seedless vascular plant. Use the proper terminology and show the ploidy levels of each structure and generation.
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What are possible explanations for the switch from haploid stage dominance to diploid stage dominance?
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Most mutations are deleterious, and haploid organisms that suffer a lethal mutation have no wild-type copy to "rescue" them from lethal mutations. For this reason, the haploid stage is more sensitive to genetic insult than is the diploid stage. Likely, the transition from a prominent haploid stage to a prominent diploid stage was adaptive for the relatively high mutation rate suffered by terrestrial plants.
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Describe the specialized gametophytic tissue that both ferns and mosses have. What purpose does it serve?
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Mosses and ferns is both have antheridia and archegonia, the specialized gametophytic tissue where gametes are produced. The archegonium is also where the egg is fertilized once the sperm from the antheridium swims through water to reach it.
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What are the most common types of seedless vascular plants surviving today? What group do they belong in?
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Ferns. They belong to the pterophyte group.
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