Plant

  • Definition of Plants

    • Terrestrial multicellular eukaryotes that conduct photosynthesis.
    • Key differences:
    • Plants differ from animals and fungi in structure and reproduction.
    • Plants uniquely have structures like roots and shoots.

  • Adaptations for Land Survival

    • Evolved around 500 million years ago.
    • Roots anchor in soil, absorb water and minerals, transport nutrients, and store food.
    • Shoots include stems and leaves, serve as aboveground structures.

  • Reproductive Structures

    • Pollen protects sperm; allows transport by wind or animals.
    • Eggs remain in female reproductive organs for embryo development.

  • Plant Anatomy

    • Vascular System: Transports water, sugar, and minerals.
    • Cuticle: Waxy coating to prevent water loss.
    • Leaves: Main sites for photosynthesis and gas exchange; contain stomata.
    • Xylem & Phloem:
    • Phloem: Transports sugars, flows from sugar source to sink.
    • Xylem: Moves water via transpiration.

  • Types of Plant Tissues

    • Organized into three systems:
    • Dermal: Protective covering, regulates gas exchange.
    • Vascular: Long-distance transport.
    • Ground: Photosynthesis, support, nutrient storage.

  • Major Plant Groups

    • Bryophytes: Seedless, nonvascular. Adapted for land with a waxy layer and gamete protection.
    • Seedless Vascular Plants: Like ferns, possess vascular tissue.
    • Gymnosperms: First seeds evolved in cones. Seeds enabled land spread.
    • Angiosperms: Flowering plants that dominate modern ecosystems; support reproductive processes through flowers and fruit.

  • Photosynthesis and Growth

    • Mass from the integration of CO₂, sunlight, and water through photosynthesis.
    • Primary growth occurs at meristem tissue at roots/stem tips.