6 Plant diversity

1. Plant Diversity

1.1 Overview of Kingdoms

• Five kingdoms of life include:

  • Animalia

  • Plantae

  • Fungi

  • Protista

  • Monera

1.2 Plant Classification

• Divided into:

  • Bryophytes

  • Pterophytes

  • Spermatophytes

    • Gymnosperms (cone-bearing plants)

    • Angiosperms (flowering plants)

2. Grouping of Plants

• Grouping is based on:

  • Vascular tissue presence or absence

  • True leaves, stems, and roots

  • Spores or seeds formation

  • Fruits, cones, or flowers presence

  • Dependency on water for reproduction

3. Types of Plants

3.1 Non-Vascular Plants

• Examples: mosses, liverworts

  • Do not have vascular tissue

3.2 Vascular Plants

3.2.1 Seedless Vascular Plants

• Examples: ferns, horsetails, club mosses

3.2.2 Seed-bearing Vascular Plants

• Includes:

  • Gymnosperms: examples include pine trees, fir trees

  • Angiosperms: examples include grasses, flowers (monocots and dicots)

4. Plant Evolution Stages

• Evolution from simple green algae to complex vascular plants:

  • Nonvascular plants (bryophytes)

  • Seedless vascular plants (pterophytes)

  • Seed-bearing plants (spermatophytes)

5. Alternation of Generations

5.1 Plant Life Cycle

• Generations:

  • Gametophyte Generation (Haploid)

    • Responsible for producing gametes (sexually)

  • Sporophyte Generation (Diploid)

    • Responsible for producing spores (asexually)

    • One generation gives rise to the other

6. Bryophytes

6.1 Characteristics

• Examples: liverworts, hornworts, moss

• Thought to be the first plants, dating back 400 million years

• Prefer cool, damp habitats

• Gametophyte generation is dominant

  • The plant body is called a thallus lacking true roots, stems, and leaves

  • Vascular tissue is absent

  • Requires water for sexual reproduction

6.2 Life Cycle

• Fertilized zygote develops into a sporophyte generation

• Dominant generation: haploid gametophyte

7. Pterophytes

7.1 Characteristics

• Primarily ferns

• Adapted to land, prefer moist, shady conditions

• Dominant generation is sporophyte

  • Features true roots, stems, and leaves

  • Vascular tissue is present

7.2 Life Cycle

• Sporophyte produces spores in structures called sorus located on leaf underside

• Water required for fertilization

8. Spermatophytes (Seed-bearing Plants)

8.1 Adaptations for Land Survival

• Fertilization no longer requires water due to pollen

• Fertilized ovule develops into a seed with protective coat

• Seeds contain an embryo with stored food, allowing survival in dry conditions

8.2 Groups of Spermatophytes

• Gymnosperms

  • Naked seeds, includes four groups: conifers, cycads, gnetales, and ginkgo

  • Characteristics:

    • Dominant sporophyte generation

    • Male and female cones, monoecious or dioecious plants

    • Cones produce pollen and ovules for reproduction

• Angiosperms

  • Seeds surrounded by fruit

  • Two groups: monocotyledonous and dicotyledonous

  • Reproductive structures are flowers with both male (stamen) and female (pistil) parts

9. Structure of Angiosperms

• Complex vascular tissue including xylem and phloem

• True leaves with cuticle and stomata

• Strongly developed root systems

10. Comparison: Monocots vs. Dicots

10.1 Monocots

• One cotyledon, parallel leaf venation, fibrous root system

10.2 Dicots

• Two cotyledons, net-like leaf venation, taproot system

11. Flower Structure

• Parts of a Flower:

  • Perianth (corolla and calyx)

  • Androecium (male parts including filament and anther)

  • Gynoecium (female parts including stigma, style, ovary)

12. Summary of Plant Types and Features