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Plants Angiosperms vs Gymnosperms Leaf Structure/Adaptations. What are the parts of a leaf? Cuticle-waxy covering to protect from water loss Palisade layer- column shaped cells containing chloroplasts, site of most photosynthesis
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What are the parts of a leaf? • Cuticle-waxy covering to protect from water loss • Palisade layer- column shaped cells containing chloroplasts, site of most photosynthesis • Spongy mesophyll- loosely packed with air spaces allowing gases to circulate • Stomata- openings in leaf for gas exchange • Guard cells- cells which control the size of the stomata
Add transpiration The evaporation of water from plants. How does this help the plant maintain homeostasis?
Leaf adaptations • spines- cactus spines protect the plant from predators & water loss B. Tendrils- leaflets that are modified for climbing
C. Thick leaves- modified for water storage D. Pitcher type leaves-modified for catching insects
Gymnosperms; • Non flowering vascular plants • Example: conifer • 1. Cone bearers: seeds found on scales of cone • 2. Needle like leaves with tough cuticle • 3. Shallow roots • 4. Bark to reduce water loss • 5. Evergreens: retain leaves all year • 6. Male cone produces pollen • 7. female cone produces seeds
Angiosperms: flower producing plants; most successful plant group on earth, 250,000 species
Plant Responses Tropism- a plants response to its environment. There are 3 types
Geotropism A plants response to gravity
Phototropism A plants response to light
Thigmotropism A plants response to touch