Plant Diversity and Evolution

Plant Diversity

Types of Plants

• Bryophytes: Non-vascular plants, e.g., mosses and liverworts
  • Lack true roots, stems, and leaves
  • Simple structure, no vascular tissue
• Pteridophytes: Vascular plants, e.g., ferns
  • Have true roots, stems, and leaves
  • Have vascular tissue (xylem and phloem)
• Gymnosperms: Seed-producing plants, e.g., conifers
  • Have seeds, but not fruits or flowers
  • Often evergreen, with needle-like leaves
• Angiosperms: Flowering plants, e.g., flowering plants and trees
  • Have seeds, fruits, and flowers
  • Most diverse group of plants

Characteristics of Plant Diversity

• Habitat: Plants can be found in almost every environment, from deserts to rainforests
• Morphology: Plants vary greatly in shape, size, and structure
• Physiology: Plants have different ways of obtaining resources, e.g., C3, C4, and CAM photosynthesis
• Reproduction: Plants reproduce in different ways, e.g., seeds, fruits, and flowers

Evolution of Plant Diversity

• Origin of Plants: Plants evolved from algae-like ancestors around 470 million years ago
• Key Innovations: Development of roots, stems, and leaves; evolution of vascular tissue; and origin of seeds and flowers
• Diversification: Plants diversified into different groups, with adaptations to different environments and ecological niches

Importance of Plant Diversity

• Ecosystem Services: Plants provide oxygen, food, shelter, and habitat for many organisms
• Food Security: Plants are the primary source of food for humans and animals
• Medicine: Plants are a source of medicinal compounds and inspiration for new medicines
• Climate Regulation: Plants play a crucial role in regulating the Earth's climate