Land Plants

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Land Plants
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Gymnosperms

• Plants that produce naked seeds
• Includes cone bearing plants (firs, pines)
• Thin, needle like leaves are a special
• adaptation to harsh weather conditions
• Developed roots that extend wide rather
• then deep

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Gymnosperms

• Habitat for various living organisms (diverse)
• Very important for raw materials (commercial)
• Rare species include ginkgoes, and cyads
• (believed to be main source of food for
• herbivorous dinosaurs)

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Angiosperms

• Over 250 000 known angiosperms
• (more than any other plant group combined)
• Very diverse and common
• Could not survive without insects
• Attractive to insects, birds and some mammals

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Plant Tissues

• Specialized for functions such as absorption,
• transport, photosynthesis, and reproduction.
• 3 types
• - Ground tissue
• - Vascular tissue
• - Dermal tissue

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Plant Tissues

• Ground Tissue
• - Helps with healing wounds, regenerating
• plants parts, photosynthesis, food, and
• water storage
• - Allows for flexibility (stalks, herbs)
• - Help provide strength and support

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Plant Tissues

• Vascular Tissue
• Includes xylem and phloem
• Phloem is mainly a living tissue,
• unlike xylem

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Plant Tissues

• Dermal Tissue
• Outermost layer epidermis
• Above ground parts waxy covering cuticle
• Protects against excessive water loss and
• Infection
• - Highly specialized cells(root hairs, leaf guard)

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Response in Plants

• Plants respond to hormones
• - can influence growth, cell
• division, and other functions

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Response in Plants

• Tropisms
• Growth toward (positive) or away (negative)
• from an environmental stimulus
• - Light, gravity, and touch

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Types of Tropisms

• Phototropism light
• leaves respond to light for photosynthesis
• Geotropism gravity
• grows in response to pressure
• Thigmotropism touch
• climbing plants (vines with tendrils)