Plant Evolution – Flashcards
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Describe two ways that a lack of lignin limits the height of bryophytes.
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The lack of lignin in bryphotes limits their height because without lignin, cell walls sre not hardened, so a tall plant body cannot be supported. Also, there is no means for supporting the tubes that carry water upward.
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In the life cycle of a moss, what environmental conditions are necessary for fertilization?
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Bryophytes depend upon the presence of standing water in teh ground during reproduction so teh sperm cell can swim to the female reproductice cell.
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What is a sporangium?
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A sporangium is a spore capsule within which haploid spores are produced by meiosis.
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What are tracheids?
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Tracheids are a series of hollow cells with thick cell walls that make up the xylem.
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What is their function in a vascular plant?
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Their function is to transport water through a plant.
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How was the ability to produce lignin significant to teh evolution of plants?
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The evolution of lignin made the cell walls of plants rigid. This enabled plants to grow upright adn reach great heights, thus filling more niches
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Moss plants are small, but ferns can grow as tall as small trees. Explain why this is so.
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Vascualr tissue supports a tall plant and carries water and nutrients from, the soil the plant's upper region. Thus ferns, which have vascular tissue, can grow tall, whereas mosses, which lack vasucualr tissue cannot grow tall.
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During the age of the dinasours, the vast majority of land plants were ferns adn mossed. Today, the majority are seed plants. Provide an explanation for this change based on the basic requirements of plants.
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Seed plants are more common today than ferns and mosses because seed plants can exist in a much greater range of habitats than ferns adn mosses. This is because seed plants do not require open ground water for reproduction
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Explain the structure and function of a seed cone. Explain respective roles in reproduction.
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Seed cones and pollen cones are structures on gymnosperms that are involed in reproduction. A seed cone is larger than a pollen cone and produces ovules, which contain the female gametophytes. Fertilization and seed developement occur within the cone.
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Explain the structure and function of a pollen cone. Explain respective roles in reproduction.
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A pollen cone is small and produces pollen, the male gametophyte stage of the gymnosperm.
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Describe the similarities between gymnosperm and angiosperm
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They both can reproduce without open water in the ground, both produce seed (protected embryos) and both produce pollen(male reproductive cell).
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Descirbe the differences between gymnosperm and angiosperm in the reproductive system
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Gymnosperms carry out reproduction in cones adn angiosperms carry out reproduction in flowers
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Descirbe the differences between gymnosperm and angiosperm in the seeds
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Gymnosperms bear seeds in cones and seeds are not protected once released and Angiosperms produce seeds that are encased in fruit.
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Descirbe the differences between gymnosperm and angiosperm in pollination
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The pollen of Gymnosperms in blown to female cones by winds and the pollen of Angiosperms is mostly transported by animals (mostly insects). Thus pollen in Angiosperms is more likely to reach its "target" than gymnosperms.
