Plant Classification: Angiosperms and Gymnosperms

Angiosperms

• Also known as flowering plants
• Most diverse group of plants, with over 400,000 species
• Characterized by:
  • Producing flowers, fruits, and seeds
  • Having true vessels (xylem and phloem) in stems
  • Having broad leaves with net-like veins
• Examples: roses, daisies, sunflowers, grasses, and trees like oak and maple

Gymnosperms

• Also known as conifers or naked seeds
• Characterized by:
  • Producing cones and seeds, but no flowers or fruits
  • Having needle-like or scale-like leaves
  • Having vascular tissue, but not true vessels
• Examples: pines, spruces, firs, cedars, cypresses, and redwoods

Bryophytes

• Also known as non-vascular plants
• Characterized by:
  • Lacking true vascular tissue (xylem and phloem)
  • Having simple, non-woody stems
  • Having leaves that lack true veins
  • Reproducing via spores, not seeds
• Examples: mosses, liverworts, and hornworts

Pteridophytes

• Also known as vascular cryptogams or ferns
• Characterized by:
  • Having vascular tissue, but not seeds
  • Having true leaves with veins
  • Reproducing via spores, not seeds
• Examples: ferns, horsetails, and club mosses

Plant Adaptations

• Desert Adaptations:
  • Deep roots to access water
  • Thick cuticles to reduce water loss
  • CAM (Crassulacean Acid Metabolism) photosynthesis to conserve water
• Tropical Rainforest Adaptations:
  • Large leaves to maximize photosynthesis
  • Epiphytic growth (growing on other plants) to access light
  • Symbiotic relationships with fungi for nutrient uptake
• Aquatic Adaptations:
  • Aerenchyma (air-filled tissue) to increase buoyancy
  • Stomata on upper leaf surfaces to reduce water loss
  • Submerged leaves with reduced cuticles to facilitate gas exchange

Angiosperms

• Most diverse group of plants, with over 400,000 species
• Characterized by producing flowers, fruits, and seeds
• Have true vessels (xylem and phloem) in stems
• Have broad leaves with net-like veins
• Examples include roses, daisies, sunflowers, grasses, and trees like oak and maple

Gymnosperms

• Characterized by producing cones and seeds, but no flowers or fruits
• Have needle-like or scale-like leaves
• Have vascular tissue, but not true vessels
• Examples include pines, spruces, firs, cedars, cypresses, and redwoods

Bryophytes

• Lack true vascular tissue (xylem and phloem)
• Have simple, non-woody stems
• Have leaves that lack true veins
• Reproduce via spores, not seeds
• Examples include mosses, liverworts, and hornworts

Pteridophytes

• Have vascular tissue, but not seeds
• Have true leaves with veins
• Reproduce via spores, not seeds
• Examples include ferns, horsetails, and club mosses

Plant Adaptations

Desert Adaptations

• Deep roots to access water
• Thick cuticles to reduce water loss
• CAM photosynthesis to conserve water

Tropical Rainforest Adaptations

• Large leaves to maximize photosynthesis
• Epiphytic growth to access light
• Symbiotic relationships with fungi for nutrient uptake

Aquatic Adaptations

• Aerenchyma to increase buoyancy
• Stomata on upper leaf surfaces to reduce water loss
• Submerged leaves with reduced cuticles to facilitate gas exchange

Plant Diversity

Bryophytes

• Characterized by lack of true leaves, stems, and roots
• Small, herbaceous, and soft-bodied
• No true vascular tissue (xylem and phloem)
• Simple, non-branching stems
• Reproduce via spores, not flowers or seeds
• Examples: mosses, liverworts, and hornworts

Angiosperms

• Produce flowers and fruits
• Seeds enclosed in ovaries
• Vascular tissue (xylem and phloem) present
• Diverse group, including trees, shrubs, and herbs
• Examples: roses, sunflowers, and oak trees

Plant Adaptations

• Specialized structures or features for survival and thriving in various environments
• Cacti: thick stems for water storage, spines for defense
• Desert plants: deep roots for water access, small leaves for reduced water loss
• Carnivorous plants: modified leaves for capturing and digesting insects
• Epiphytes: aerial roots for nutrient absorption, adapted to live on other plants

Pteridophytes

• Vascular plants with true leaves (megaphylls) and veins
• Vascular tissue (xylem and phloem) present
• Spores produced in sporangia on underside of leaves
• No seeds or flowers
• Examples: ferns, horsetails, and club mosses

Gymnosperms

• Seed-producing plants with vascular tissue (xylem and phloem)
• Produce seeds, but not enclosed in ovaries
• Cones or cone-like structures for reproduction
• Evergreen or deciduous, with needle-like or scale-like leaves
• Examples: pines, spruces, and cycads