Plant Form and Function

PLANT FORM AND FUNCTION

Introduction

  • Botany: Scientific study of plants, also known as plant science, plant biology, or phytology.
  • Origins in herbalism, evolving to include: plant structure, physiology, ecology, distribution, classification, reproduction, and environmental interactions.

Characteristics of Plants

  • Living organisms, eukaryotic, autotrophic, multicellular.
  • Features: Cell wall (cellulose), chloroplasts for photosynthesis, waxy cuticle, stomata.

Requirements for Plant Growth

  • Essential needs: Light, Water, Nutrients, Carbon dioxide, Space.

Importance of Plants

  • Key roles: Oxygen production, food source, shelter, medicine.

Classification of Plants

  • Four major groups:
    1. Bryophytes – Mosses
    2. Pteridophytes – Ferns
    3. Gymnosperms – Conifers
    4. Angiosperms – Flowering plants (Monocots & Dicots).
Bryophytes
  • 15,000 species, small (<20 cm), oldest and poorly adapted to land.
  • Examples: Mosses, hornworts, liverworts; require moist environments for reproduction.
Pteridophytes
  • 11,000 species, seedless vascular plants, mainly terrestrial.
  • Require water for sexual reproduction.
Gymnosperms
  • 760 species, vascular seed plants with naked seeds.
  • Mostly woody trees, shrubs; seeds usually exposed on cones.
Angiosperms
  • 235,000 species; vascular plants reproducing via flowers/fruits.
  • Characteristics: Adaptable vegetative organs, efficient transport tissues (xylem/phloem), diverse flowers, seeds within fruit for better protection and dispersal.