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25 Cards in this Set
- Front
- Back
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origin of plants
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475 million years ago (mya)
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origin of vascular plants
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420 million years ago
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origin of seeds
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360 million years ago
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origin of living seed plants (extant plant species)
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305 million years ago
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origin of flowers
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130 million years ago
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plant environments
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mostly terrestrial but some sea grasses are aquatic
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"Land Plants"
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term used to describe all true plants to distinguish them from the strictly aquatic algae
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plants supply:
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1. oxygen
2. food source for land animals |
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Charophytes or Charophyceans
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a group of Green Algae that is the closest relatives of land plants
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characteristics shared between Land Plants and Algal groups
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1. Many algae are multicellular, eukaryotic photoautotrophs... (as are plants)
2. Many algae have cell walls made of cellulose... (as do plants) 3. Possess chlorophylls A and B in chloroplasts.. (as do plants) |
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key traits shared between only Land plants and Charophytes
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1. Rose-shaped complexes for cellulose synthesis
2. Peroxisome enzymes 3. structure of flagellated sperm 4. Formation of a phragmoplast during cell division |
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Peroxisome enzymes
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reduce the loss of carbohydrates to photorespiration
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sporopollenin
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a layer of durable polymer that prevents exposed zygotes from drying out
"pre-adapted" plants for the move to land |
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Benefits of movement onto land
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1. More room
2. unfiltered sunlight 3. more plentiful co2 4. nutrient-rich soil 5. few herbivors or pathogens |
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challenges of movement onto land
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1. scarcity of water
2. lack of structural support... water is very supportive because it is more dense than air |
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different boundaries of the plant kingdom
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1. Kingdom Plantae
2. Kingdom Streptophyta 3. Kingdom Viridiplantae |
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Kingdom Plantae
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Systematic groups that includes only land plants
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Kingdom Streptophyta
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systematic grouping that includes some charophytes with the land plants
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Kingdom Viridiplantae
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systematic grouping that includes all of the chlorophytes with the charophytes and land plants
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derived traits of plants
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there are four key traits in nearly all land plants but are absent in the charophytes
1. Alternation of generations with multicellular dependent embryos 2. walled spores produced in sporangia 3. multicelluar gametangia 4. apical meristems |
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Additional derived traits
(in some but not all plant species) |
1. Cuticle, stomata, and vascular tissue for acquiring, transporting and conserving water
2. adaptations for reducing the harmful effect of UV radiation 3. secondary coumpouds for repelling terrestrial herbivores and resisting pathogens |
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cuticle
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a waxy covering on the surface of stems and leaves that helps to prevent water loss
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stomata
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a microscopic pore in the epidermis of leaves and stems that allows gas exchange between the interior of the plant and the surrounding environment
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vascular tissue
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plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body
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sporangia
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a multicellular organ in plants that produces spores through meiosis
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